From 1575d4f53805f177474b5bb96daebede9b2dfb73 Mon Sep 17 00:00:00 2001
From: root <root@ka-ata-killa.ourano.james.local>
Date: Wed, 24 Feb 2021 23:45:58 +0000
Subject: base
---
docs/Acorn_BBCSMOct85_Sec1.pdf | Bin 0 -> 6708693 bytes
docs/README | 6 +
docs/SN76489.pdf | Bin 0 -> 249096 bytes
docs/keyboard.odg | Bin 0 -> 16836 bytes
docs/keyboard.png | Bin 0 -> 60246 bytes
docs/keyboard.txt | 81 +
docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/C000 | 876 ++++++++++
docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/C300 | 1 +
docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/C4C0 | 1 +
docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/C735 | 1 +
docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/CA39 | 1 +
docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/CDED | 1 +
docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/D10D | 1 +
docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/D4BF | 1 +
docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/D940 | 1 +
docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/DC1C | 1 +
docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/DF0C | 512 ++++++
docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/E20E | 1 +
docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/E435 | 1 +
docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/E6B0 | 1 +
docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/E887 | 1 +
docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/EAD9 | 1 +
docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/EEDA | 1 +
docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/F135 | 549 +++++++
docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/F3CA | 1 +
docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/F68B | 1 +
docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/F9B4 | 1 +
docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/FC00 | 1 +
docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/Microbase | 1682 ++++++++++++++++++++
docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/index.html | 80 +
docs/texas_instruments_sn76489an.pdf | Bin 0 -> 344223 bytes
31 files changed, 3805 insertions(+)
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create mode 100644 docs/README
create mode 100644 docs/SN76489.pdf
create mode 100644 docs/keyboard.odg
create mode 100644 docs/keyboard.png
create mode 100644 docs/keyboard.txt
create mode 100644 docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/C000
create mode 100644 docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/C300
create mode 100644 docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/C4C0
create mode 100644 docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/C735
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create mode 100644 docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/D4BF
create mode 100644 docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/D940
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create mode 100644 docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/DF0C
create mode 100644 docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/E20E
create mode 100644 docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/E435
create mode 100644 docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/E6B0
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create mode 100644 docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/EAD9
create mode 100644 docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/EEDA
create mode 100644 docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/F135
create mode 100644 docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/F3CA
create mode 100644 docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/F68B
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create mode 100644 docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/index.html
create mode 100644 docs/texas_instruments_sn76489an.pdf
(limited to 'docs')
diff --git a/docs/Acorn_BBCSMOct85_Sec1.pdf b/docs/Acorn_BBCSMOct85_Sec1.pdf
new file mode 100644
index 0000000..c0a47b5
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diff --git a/docs/README b/docs/README
new file mode 100644
index 0000000..47daf92
--- /dev/null
+++ b/docs/README
@@ -0,0 +1,6 @@
+T65 implementation from http://www.fpgaarcade.com/resources/T65_v302.zip (bug fixes from PACE dev)
+M6522 implementation from FPGA arcade VIC20 design. Various bug fixes added locally.
+SN76489 implementation by Arnim Laeuger and obtained from FPGA arcade
+
+
+
diff --git a/docs/SN76489.pdf b/docs/SN76489.pdf
new file mode 100644
index 0000000..b103f37
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diff --git a/docs/keyboard.odg b/docs/keyboard.odg
new file mode 100644
index 0000000..403b1e7
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diff --git a/docs/keyboard.png b/docs/keyboard.png
new file mode 100644
index 0000000..12735bd
Binary files /dev/null and b/docs/keyboard.png differ
diff --git a/docs/keyboard.txt b/docs/keyboard.txt
new file mode 100644
index 0000000..d63fa03
--- /dev/null
+++ b/docs/keyboard.txt
@@ -0,0 +1,81 @@
+Column Row Key PC key Scancode
+0 0 SHIFT LEFT SHIFT, RIGHT SHIFT 12 + 59
+0 1 Q Q 15
+0 2 F0 F10 09
+0 3 1 (!) 1 16
+0 4 CAPS LOCK CAPS LOCK 58
+0 5 SHIFT LOCK LEFT ALT 11
+0 6 TAB TAB 0D
+0 7 ESCAPE ESCAPE 76
+1 0 CTRL LEFT CTRL, RIGHT CTRL 14 + E0,14
+1 1 3 (#) 3 26
+1 2 W W 1D
+1 3 2 (") 2 1E
+1 4 A A 1C
+1 5 S S 1B
+1 6 Z Z 1A
+1 7 F1 F1 05
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+2 1 4 ($) 4 25
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+2 3 D D 23
+2 4 X X 22
+2 5 C C 21
+2 6 SPACE SPACE 29
+2 7 F2 F2 06
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+3 3 R R 2D
+3 4 F F 2B
+3 5 G G 34
+3 6 V V 2A
+3 7 F3 F3 04
+4 0 DIP 5
+4 1 F4 F4 0C
+4 2 7 (') 7 3D
+4 3 6 (&) 6 36
+4 4 Y Y 35
+4 5 H H 33
+4 6 B B 32
+4 7 F5 F5 03
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+5 1 8 (() 8 3E
+5 2 I I 43
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+5 4 J J 3B
+5 5 N N 31
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+5 7 F6 F6 0B
+6 0 DIP 3
+6 1 F7 F7 83
+6 2 9 ()) 9 46
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+6 6 , (<) , 41
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+7 3 P P 4D
+7 4 @ ` 0E
+7 5 ; (+) ; 4C
+7 6 . (>) . 49
+7 7 F9 F9 01
+8 0 DIP 1
+8 1 ^ (~) = 55
+8 2 _ (£) # 5D
+8 3 [ ({) [ 54
+8 4 : (*) ' 52
+8 5 ] (}) ] 5B
+8 6 / (?) / 4A
+8 7 \ (|) \ 61
+9 0 DIP 0
+9 1 LEFT LEFT E0,6B
+9 2 DOWN DOWN E0,72
+9 3 UP UP E0,75
+9 4 RETURN RETURN 5A
+9 5 DELETE BACKSPACE 66
+9 6 COPY END E0,69
+9 7 RIGHT RIGHT E0,74
diff --git a/docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/C000 b/docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/C000
new file mode 100644
index 0000000..ccfc412
--- /dev/null
+++ b/docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/C000
@@ -0,0 +1,876 @@
+BBC Operating System OS 1.20
+============================
+Commented disassembly by Geoff Cox, originally published on Micronet.
+Additional comments by J.G.Harston.
+
+***************** VDU CHARACTER FONT LOOK UP TABLE ****************************
+
+These are the default definitions for characters 32-127. The are accessed with
+OSWORD 10 (read character definition) and reprogrammed with VDU 23 (define
+character). If the character set is not exploded, then a block of 32 characters
+is copied to the soft character buffer at &0C00 when a character is defined.
+
+C000 DB 00 ;00000000 ........ &20 32 - ' '
+C001 DB 00 ;00000000 ........
+C002 DB 00 ;00000000 ........
+C003 DB 00 ;00000000 ........
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+C007 DB 00 ;00000000 ........
+
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+C00C DB 18 ;00011000 ...**...
+C00D DB 00 ;00000000 ........
+C00E DB 18 ;00011000 ...**...
+C00F DB 00 ;00000000 ........
+
+C010 DB 6C ;01101100 .**.**.. &22 34 - '"'
+C011 DB 6C ;01101100 .**.**..
+C012 DB 6C ;01101100 .**.**..
+C013 DB 00 ;00000000 ........
+C014 DB 00 ;00000000 ........
+C015 DB 00 ;00000000 ........
+C016 DB 00 ;00000000 ........
+C017 DB 00 ;00000000 ........
+
+C018 DB 36 ;00110110 ..**.**. &23 35 - '#'
+C019 DB 36 ;00110110 ..**.**.
+C01A DB 7F ;01111111 .*******
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+C01C DB 7F ;01111111 .*******
+C01D DB 36 ;00110110 ..**.**.
+C01E DB 36 ;00110110 ..**.**.
+C01F DB 00 ;00000000 ........
+
+C020 DB 0C ;00001100 ....**.. &24 36 - '$'
+C021 DB 3F ;00111111 ..******
+C022 DB 68 ;01101000 .**.*...
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+C026 DB 18 ;00011000 ...**...
+C027 DB 00 ;00000000 ........
+
+C028 DB 60 ;01100000 .**..... &25 37 - '%'
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+
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+
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+
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+
+C150 DB 3E ;00111110 ..*****. &4A 74 - 'J'
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+
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+
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+
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+
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+
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+
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+C282 DB 7C ;01111100 .*****..
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+
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+
+C290 DB 00 ;00000000 ........ &72 114 - 'r'
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+
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+C2BE DB 36 ;00110110 ..**.**.
+C2BF DB 00 ;00000000 ........
+
+C2C0 DB 00 ;00000000 ........ &78 120 - 'x'
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+
+C2C8 DB 00 ;00000000 ........ &79 121 - 'y'
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+
+C2D0 DB 00 ;00000000 ........ &7A 122 - 'z'
+C2D1 DB 00 ;00000000 ........
+C2D2 DB 7E ;01111110 .******.
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+C2D6 DB 7E ;01111110 .******.
+C2D7 DB 00 ;00000000 ........
+
+C2D8 DB 0C ;00001100 ....**.. &7B 123 - '{'
+C2D9 DB 18 ;00011000 ...**...
+C2DA DB 18 ;00011000 ...**...
+C2DB DB 70 ;01110000 .***....
+C2DC DB 18 ;00011000 ...**...
+C2DD DB 18 ;00011000 ...**...
+C2DE DB 0C ;00001100 ....**..
+C2DF DB 00 ;00000000 ........
+
+C2E0 DB 18 ;00011000 ...**... &7C 124 - '|'
+C2E1 DB 18 ;00011000 ...**...
+C2E2 DB 18 ;00011000 ...**...
+C2E3 DB 00 ;00000000 ........
+C2E4 DB 18 ;00011000 ...**...
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+C2E6 DB 18 ;00011000 ...**...
+C2E7 DB 00 ;00000000 ........
+
+C2E8 DB 30 ;00110000 ..**.... &7D 125 - '}'
+C2E9 DB 18 ;00011000 ...**...
+C2EA DB 18 ;00011000 ...**...
+C2EB DB 0E ;00001110 ....***.
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+C2EE DB 30 ;00110000 ..**....
+C2EF DB 00 ;00000000 ........
+
+C2F0 DB 31 ;00110001 ..**...* &7E 126 - '~'
+C2F1 DB 6B ;01101011 .**.*.**
+C2F2 DB 46 ;01000110 .*...**.
+C2F3 DB 00 ;00000000 ........
+C2F4 DB 00 ;00000000 ........
+C2F5 DB 00 ;00000000 ........
+C2F6 DB 00 ;00000000 ........
+C2F7 DB 00 ;00000000 ........
+
+C2F8 DB FF ;11111111 ******** &7F 127 - DEL
+C2F9 DB FF ;11111111 ********
+C2FA DB FF ;11111111 ********
+C2FB DB FF ;11111111 ********
+C2FC DB FF ;11111111 ********
+C2FD DB FF ;11111111 ********
+C2FE DB FF ;11111111 ********
+C2FF DB FF ;11111111 ********
+
diff --git a/docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/C300 b/docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/C300
new file mode 100644
index 0000000..83abcfd
--- /dev/null
+++ b/docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/C300
@@ -0,0 +1 @@
+BBC Operation System OS 1.20 Startup Strings and Tables
C300 JMP &CB1D ;Initialise screen with mode in A.
C303 DB 13,'BBC Computer ',0
C312 DB '16K',7,0
C317 DB '32K',7,0
C31C DB 08,0D,0D ;Termination byte in next table
****** 16 COLOUR MODE BYTE MASK LOOK UP TABLE******
C31F DB 00 ;00000000
C320 DB 11 ;00010001
C321 DB 22 ;00100010
C322 DB 33 ;00110011
C323 DB 44 ;01000100
C324 DB 55 ;01010101
C325 DB 66 ;01100110
C326 DB 77 ;01110111
C327 DB 88 ;10001000
C328 DB 99 ;10011001
C329 DB AA ;10101010
C32A DB BB ;10111011
C32B DB CC ;11001100
C32C DB DD ;11011101
C32D DB EE ;11101110
C32E DB FF ;11111111
****** 4 COLOUR MODE BYTE MASK LOOK UP TABLE******
C32F DB 00 ;00000000
C330 DB 55 ;01010101
C331 DB AA ;10101010
C332 DB FF ;11111111
****** VDU ENTRY POINT LO LOOK UP TABLE******
C333 DB 11 ;00010001
C334 DB 3B ;00111011
C335 DB 96 ;10010110
C336 DB A1 ;10100001
C337 DB AD ;10101101
C338 DB B9 ;10111001
C339 DB 11 ;00010001
C33A DB 6F ;01101111
C33B DB C5 ;11000101
C33C DB 64 ;01100100
C33D DB F0 ;11110000
C33E DB 5B ;01011011
C33F DB 59 ;01011001
C340 DB AF ;10101111
C341 DB 8D ;10001101
C342 DB A6 ;10100110
C343 DB C0 ;11000000
C344 DB F9 ;11111001
C345 DB FD ;11111101
C346 DB 92 ;10010010
C347 DB 39 ;00111001
C348 DB 9B ;10011011
C349 DB EB ;11101011
C34A DB F1 ;11110001
C34B DB 39 ;00111001
C34C DB 8C ;10001100
C34D DB BD ;10111101
C34E DB 11 ;00010001
C34F DB FA ;11111010
C350 DB A2 ;10100010
C351 DB 79 ;01111001
C352 DB 87 ;10000111
C353 DB AC ;10101100
****** VDU ENTRY POINT HI PARAMETER LOOK UP TABLE******
; 1xxxxxxx - no parameters, address high byte
; 0aaapppp - parameter count 16-p, address high byte &C3+a
C354 DB C5 ;11000101 VDU 0 - &C511, no parameters
C355 DB 2F ;00101111 VDU 1 - &C53B, 1 parameter
C356 DB C5 ;11000101 VDU 2 - &C596, no parameters
C357 DB C5 ;11000101 VDU 3 - &C5A1, no parameters
C358 DB C5 ;11000101 VDU 4 - &C5AD, no parameters
C359 DB C5 ;11000101 VDU 5 - &C5B9, no parameters
C35A DB C5 ;11000101 VDU 6 - &C511, no parameters
C35B DB E8 ;11101000 VDU 7 - &E86F, no parameters
C35C DB C5 ;11000101 VDU 8 - &C5C5, no parameters
C35D DB C6 ;11000110 VDU 9 - &C664, no parameters
C35E DB C6 ;11000110 VDU 10 - &C6F0, no parameters
C35F DB C6 ;11000110 VDU 11 - &C65B, no parameters
C360 DB C7 ;11000111 VDU 12 - &C759, no parameters
C361 DB C7 ;11000111 VDU 13 - &C7AF, no parameters
C362 DB C5 ;11000101 VDU 14 - &C58D, no parameters
C363 DB C5 ;11000101 VDU 15 - &C5A6, no parameters
C364 DB C7 ;11000111 VDU 16 - &C7C0, no parameters
C365 DB 4F ;01001111 VDU 17 - &C7F9, 1 parameter
C366 DB 4E ;01001110 VDU 18 - &C7FD, 2 parameters
C367 DB 5B ;01011011 VDU 19 - &C892, 5 parameters
C368 DB C8 ;11001000 VDU 20 - &C839, no parameters
C369 DB C5 ;11000101 VDU 21 - &C59B, no parameters
C36A DB 5F ;01011111 VDU 22 - &C8EB, 1 parameter
C36B DB 57 ;01010111 VDU 23 - &C8F1, 9 parameters
C36C DB 78 ;01111000 VDU 24 - &CA39, 8 parameters
C36D DB 6B ;01101011 VDU 25 - &C9AC, 5 parameters
C36E DB C9 ;11001001 VDU 26 - &C9BD, no parameters
C36F DB C5 ;11000101 VDU 27 - &C511, no parameters
C370 DB 3C ;00111100 VDU 28 - &C6FA, 4 parameters
C371 DB 7C ;01111100 VDU 29 - &CAA2, 4 parameters
C372 DB C7 ;11000111 VDU 30 - &C779, no parameters
C373 DB 4E ;01001110 VDU 31 - &C787, 2 parameters
C374 DB CA ;11001010 VDU 127 - &CAAC, no parameters
****** 640 MULTIPLICATION TABLE 40COL, 80COL MODES HIBYTE, LOBYTE ******
C375 DW 0000 ; 0*640 = &0000
C377 DW 8002 ; 1*640 = &0280
C379 DW 0005 ; 2*640 = &0500
C37B DW 8007 ; 3*640 = &0780
C37D DW 000A ; 4*
C37F DW 800C ; 5*
C381 DW 000F ; 6*
C383 DW 8011 ; 7*
C385 DW 0014 ; 8*
C387 DW 8016 ; 9*
C389 DW 0019 ; 10*
C38B DW 801B ; 11*
C38D DW 001E ; 12*
C38F DW 8020 ; 13*
C391 DW 0023 ; 14*
C393 DW 8025 ; 15*
C395 DW 0028 ; 16*
C397 DW 802A ; 17*
C399 DW 002D ; 18*
C39B DW 802F ; 19*
C39D DW 0032 ; 20*
C39F DW 8034 ; 21*
C3A1 DW 0037 ; 22*
C3A3 DW 8039 ; 23*
C3A5 DW 003C ; 24*
C3A7 DW 803E ; 25*
C3A9 DW 0041 ; 26*
C3AB DW 8043 ; 27*
C3AD DW 0046 ; 28*
C3AF DW 8048 ; 29*
C3B1 DW 004B ; 30*
C3B3 DW 804D ; 31*640 = &4D80
****** *40 MULTIPLICATION TABLE TELETEXT MODE HIBYTE, LOBYTE ******
C3B5 DW 0000 ; 0*40 = &0000
C3B7 DW 2800 ; 1*40 = &0028
C3B9 DW 5000 ; 2
C3BB DW 7800 ; 3
C3BD DW A000 ; 4
C3BF DW C800 ; 5
C3C1 DW F000 ; 6
C3C3 DW 1801 ; 7
C3C5 DW 4001 ; 8
C3C7 DW 6801 ; 9
C3C9 DW 9001 ; 10
C3CB DW B801 ; 11
C3CD DW E001 ; 12
C3CF DW 0802 ; 13
C3D1 DW 3002 ; 14
C3D3 DW 5802 ; 15
C3D5 DW 8002 ; 16
C3D7 DW A802 ; 17
C3D9 DW D002 ; 18
C3DB DW F802 ; 19
C3DD DW 2003 ; 20
C3DF DW 4803 ; 21
C3E1 DW 7003 ; 22
C3E3 DW 9803 ; 23*40 = &0398
C3E5 DW C003 ; 24*40 = &03C0
****** TEXT WINDOW -BOTTOM ROW LOOK UP TABLE ******
C3E7 DB 1F ; MODE 0 - 32 ROWS
C3E8 DB 1F ; MODE 1 - 32 ROWS
C3E9 DB 1F ; MODE 2 - 32 ROWS
C3EA DB 18 ; MODE 3 - 25 ROWS
C3EB DB 1F ; MODE 4 - 32 ROWS
C3EC DB 1F ; MODE 5 - 32 ROWS
C3ED DB 18 ; MODE 6 - 25 ROWS
C3EE DB 18 ; MODE 7 - 25 ROWS
****** TEXT WINDOW -RIGHT HAND COLUMN LOOK UP TABLE ******
C3EF DB 4F ; MODE 0 - 80 COLUMNS
C3F0 DB 27 ; MODE 1 - 40 COLUMNS
C3F1 DB 13 ; MODE 2 - 20 COLUMNS
C3F2 DB 4F ; MODE 3 - 80 COLUMNS
C3F3 DB 27 ; MODE 4 - 40 COLUMNS
C3F4 DB 13 ; MODE 5 - 20 COLUMNS
C3F5 DB 27 ; MODE 6 - 40 COLUMNS
C3F6 DB 27 ; MODE 7 - 40 COLUMNS
*************************************************************************
* *
* SEVERAL OF THE FOLLOWING TABLES OVERLAP EACH OTHER *
* SOME ARE DUAL PURPOSE *
* *
*************************************************************************
************** VIDEO ULA CONTROL REGISTER SETTINGS ***********************
C3F7 DB 9C ;10011100
C3F8 DB D8 ;11011000
C3F9 DB F4 ;11110100
C3FA DB 9C ;10011100
C3FB DB 88 ;10001000
C3FC DB C4 ;11000100
C3FD DB 88 ;10001000
C3FE DB 4B ;01001011
******** NUMBER OF BYTES PER CHARACTER FOR EACH DISPLAY MODE ************
C3FF DB 08 ;00001000
C400 DB 10 ;00010000
C401 DB 20 ;00100000
C402 DB 08 ;00001000
C403 DB 08 ;00001000
C404 DB 10 ;00010000
C405 DB 08 ;00001000
C406 DB 01 ;00000001
******************* MASK TABLE FOR 2 COLOUR MODES **********************
C407 DB AA ;10101010
C408 DB 55 ;01010101
****************** MASK TABLE FOR 4 COLOUR MODES ***********************
C409 DB 88 ;10001000
C40A DB 44 ;01000100
C40B DB 22 ;00100010
C40C DB 11 ;00010001
********** MASK TABLE FOR 4 COLOUR MODES FONT FLAG MASK TABLE **********
C40D DB 80 ;10000000
C40E DB 40 ;01000000
C40F DB 20 ;00100000
C410 DB 10 ;00010000
C411 DB 08 ;00001000
C412 DB 04 ;00000100
C413 DB 02 ;00000010 - NEXT BYTE IN FOLLOWING TABLE
********* NUMBER OF TEXT COLOURS -1 FOR EACH MODE ************************
C414 DB 01 ; MODE 0 - 2 COLOURS
C415 DB 03 ; MODE 1 - 4 COLOURS
C416 DB 0F ; MODE 2 - 16 COLOURS
C417 DB 01 ; MODE 3 - 2 COLOURS
C418 DB 01 ; MODE 4 - 2 COLOURS
C419 DB 03 ; MODE 5 - 4 COLOURS
C41A DB 01 ; MODE 6 - 2 COLOURS
C41B DB 00 ; MODE 7 - 1 'COLOUR'
************** GCOL PLOT OPTIONS PROCESSING LOOK UP TABLE ***************
C41C DB FF ;11111111
C41D DB 00 ;00000000
C41E DB 00 ;00000000
C41F DB FF ;11111111
C420 DB FF ;11111111
C421 DB FF ;11111111
C422 DB FF ;11111111
C423 DB 00 ;00000000
********** 2 COLOUR MODES PARAMETER LOOK UP TABLE WITHIN TABLE **********
C424 DB 00 ;00000000
C425 DB FF ;11111111
*************** 4 COLOUR MODES PARAMETER LOOK UP TABLE ******************
C426 DB 00 ;00000000
C427 DB 0F ;00001111
C428 DB F0 ;11110000
C429 DB FF ;11111111
***************16 COLOUR MODES PARAMETER LOOK UP TABLE ******************
C42A DB 00 ;00000000
C42B DB 03 ;00000011
C42C DB 0C ;00001100
C42D DB 0F ;00001111
C42E DB 30 ;00110000
C42F DB 33 ;00110011
C430 DB 3C ;00111100
C431 DB 3F ;00111111
C432 DB C0 ;11000000
C433 DB C3 ;11000011
C434 DB CC ;11001100
C435 DB CF ;11001111
C436 DB F0 ;11110000
C437 DB F3 ;11110011
C438 DB FC ;11111100
C439 DB FF ;11111111
********** DISPLAY MODE PIXELS/BYTE-1 LOOK UP TABLE *********************
C43A DB 07 ; MODE 0 - 8 PIXELS/BYTE
C43B DB 03 ; MODE 1 - 4 PIXELS/BYTE
C43C DB 01 ; MODE 2 - 2 PIXELS/BYTE
C43D DB 00 ; MODE 3 - 1 PIXEL/BYTE (NON-GRAPHICS)
C43E DB 07 ; MODE 4 - 8 PIXELS/BYTE
C43F DB 03 ; MODE 5 - 4 PIXELS/BYTE
********* SCREEN DISPLAY MEMORY INDEX LOOK UP TABLE OVERLAPS ************
C440 DB 00 ; MODE 6 - 1 PIXEL/BYTE // MODE 0 - TYPE 0
***** SOUND PITCH OFFSET BY CHANNEL LOOK UP TABLE WITHIN TABLE **********
C441 DB 00 ; MODE 7 - 1 PIXEL/BYTE // MODE 1 - TYPE 0 // CHANNEL 0
C442 DB 00 ; MODE 2 - TYPE 0 // CHANNEL 1
C443 DB 01 ; MODE 3 - TYPE 1 // CHANNEL 2
C444 DB 02 ; MODE 4 - TYPE 2 // CHANNEL 3
**** REST OF DISPLAY TABLE ****
C445 DB 02 ; MODE 5 - TYPE 2
C446 DB 03 ; MODE 6 - TYPE 3
C447 DB 04 ; MODE 7 - TYPE 4
***************** VDU SECTION CONTROL NUMBERS ***************************
C447 DB 04 ; MODE 7 - TYPE 4
C448 DB 00 ;00000000
C449 DB 06 ;00000110
C44A DB 02 ;00000010
*********** CRTC SET UP PARAMETERS TABLE 1 WITHIN TABLE ******************
C44B DB 0D ;00001101
C44C DB 05 ;00000101
C44D DB 0D ;00001101
C44E DB 05 ;00000101
*********** CRTC SET UP PARAMETERS TABLE 2 WITHIN TABLE *****************
C44F DB 04 ;00000100
C450 DB 04 ;00000100
C451 DB 0C ;00001100
C452 DB 0C ;00001100
C453 DB 04 ;00000100
**** REST OF VDU SECTION CONTROL NUMBERS ****
C454 DB 02 ;00000010
C455 DB 32 ;00110010
C456 DB 7A ;01111010
C457 DB 92 ;10010010
C458 DB E6 ;11100110
************** MSB OF MEMORY OCCUPIED BY SCREEN BUFFER *****************
C459 DB 50 ; Type 0: &5000 - 20k
C45A DB 40 ; Type 1: &4000 - 16k
C45B DB 28 ; Type 2: &2800 - 10k
C45C DB 20 ; Type 3: &2000 - 8k
C45D DB 04 ; Type 4: &0400 - 1k
************ MSB OF FIRST LOCATION OCCUPIED BY SCREEN BUFFER ************
C45E DB 30 ; Type 0: &3000
C45F DB 40 ; Type 1: &4000
C460 DB 58 ; Type 2: &5800
C461 DB 60 ; Type 3: &6000
C462 DB 7C ; Type 4: &7C00
***************** NUMBER OF BYTES PER ROW *******************************
C463 DB 28 ;00101000
C464 DB 40 ;01000000
C465 DB 80 ;10000000
******** ROW MULTIPLIACTION TABLE POINTER TO LOOK UP TABLE **************
C466 DB B5 ;10110101
C467 DB 75 ;01110101
C468 DB 75 ;01110101
********** CRTC CURSOR END REGISTER SETTING LOOK UP TABLE ***************
C469 DB 0B ;00001011
C46A DB 17 ;00010111
C46B DB 23 ;00100011
C46C DB 2F ;00101111
C46D DB 3B ;00111011
************* 6845 REGISTERS 0-11 FOR MODES 0-2 *************************
C46E DB 7F ;01111111
C46F DB 50 ;01010000
C470 DB 62 ;01100010
C471 DB 28 ;00101000
C472 DB 26 ;00100110
C473 DB 00 ;00000000
C474 DB 20 ;00100000
C475 DB 22 ;00100010
C476 DB 01 ;00000001
C477 DB 07 ;00000111
C478 DB 67 ;01100111
C479 DB 08 ;00001000
************* 6845 REGISTERS 0-11 FOR MODE 3 ****************************
C47A DB 7F ;01111111
C47B DB 50 ;01010000
C47C DB 62 ;01100010
C47D DB 28 ;00101000
C47E DB 1E ;00011110
C47F DB 02 ;00000010
C480 DB 19 ;00011001
C481 DB 1B ;00011011
C482 DB 01 ;00000001
C483 DB 09 ;00001001
C484 DB 67 ;01100111
C485 DB 09 ;00001001
************ 6845 REGISTERS 0-11 FOR MODES 4-5 **************************
C486 DB 3F ;00111111
C487 DB 28 ;00101000
C488 DB 31 ;00110001
C489 DB 24 ;00100100
C48A DB 26 ;00100110
C48B DB 00 ;00000000
C48C DB 20 ;00100000
C48D DB 22 ;00100010
C48E DB 01 ;00000001
C48F DB 07 ;00000111
C490 DB 67 ;01100111
C491 DB 08 ;00001000
********** 6845 REGISTERS 0-11 FOR MODE 6 *******************************
C492 DB 3F ;00111111
C493 DB 28 ;00101000
C494 DB 31 ;00110001
C495 DB 24 ;00100100
C496 DB 1E ;00011110
C497 DB 02 ;00000010
C498 DB 19 ;00011001
C499 DB 1B ;00011011
C49A DB 01 ;00000001
C49B DB 09 ;00001001
C49C DB 67 ;01100111
C49D DB 09 ;00001001
********* 6845 REGISTERS 0-11 FOR MODE 7 *****************************
C49E DB 3F ;00111111
C49F DB 28 ;00101000
C4A0 DB 33 ;00110011
C4A1 DB 24 ;00100100
C4A2 DB 1E ;00011110
C4A3 DB 02 ;00000010
C4A4 DB 19 ;00011001
C4A5 DB 1B ;00011011
C4A6 DB 93 ;10010011
C4A7 DB 12 ;00010010
C4A8 DB 72 ;01110010
C4A9 DB 13 ;00010011
************* VDU ROUTINE VECTOR ADDRESSES ******************************
C4AA DB 86 ;10000110
C4AB DB D3 ;11010011
C4AC DB 7E ;01111110
C4AD DB D3 ;11010011
************ VDU ROUTINE BRANCH VECTOR ADDRESS LO ***********************
C4AE DB 6A ;01101010
C4AF DB 74 ;01110100
C4B0 DB 42 ;01000010
C4B1 DB 4B ;01001011
************ VDU ROUTINE BRANCH VECTOR ADDRESS HI ***********************
C4B2 DB D3 ;11010011
C4B3 DB D3 ;11010011
C4B4 DB D3 ;11010011
C4B5 DB D3 ;11010011
*********** TELETEXT CHARACTER CONVERSION TABLE ************************
C4B6 DB 23 ; '#' -> '_'
C4B7 DB 5F ; '_' -> '`'
C4B8 DB 60 ; '`' -> '#'
C4B9 DB 23 ; '#'
*********** SOFT CHARACTER RAM ALLOCATION *****************************
C4BA DB 04 ; &20-&3F - OSHWM+&0400
C4BB DB 05 ; &40-&5F - OSHWM+&0500
C4BC DB 06 ; &60-&7F - OSHWM+&0600
C4BD DB 00 ; &80-&9F - OSHWM+&0000
C4BE DB 01 ; &A0-&BF - OSHWM+&0100
C4BF DB 02 ; &C0-&DF - OSHWM+&0200
*************************************************************************
* *
* VDU FUNCTIONS ADDRESSES *
* *
*************************************************************************
; VDU Address Parameters function
; 0 &C511 0 does nothing
; 1 &C53B 1 next character to printer only
; 2 &C596 0 enable printer
; 3 &C5A1 0 disable printer
; 4 &C5AD 0 select text cursor
; 5 &C5B9 0 select graphics cursor
; 6 &C511 0 enable display
; 7 &E86F 0 bell
; 8 &C5C5 0 cursor left
; 9 &C664 0 cursor right
; 10 &C6F0 0 cursor down
; 11 &C65B 0 cursor up
; 12 &C759 0 clear text window
; 13 &C7AF 0 newline
; 14 &C58D 0 select paged mode
; 15 &C5A6 0 cancel paged mode
; 16 &C7C0 0 clear graphics screen
; 17 &C7F9 1 define text colour
; 18 &C7FD 2 define graphics colour
; 19 &C892 5 define logical colour
; 20 &C839 0 restore default colours
; 21 &C59B 0 disable display
; 22 &C8EB 1 select screen MODE
; 23 &C8F1 9 define character
; 24 &CA39 8 define graphics window
; 25 &C98C 5 PLOT
; 26 &C9BD 0 set default windows
; 27 &C511 0 ESCAPE (does nothing)
; 28 &C6FA 4 define text window
; 29 &CAA2 4 define graphics origin
; 30 &C779 0 home cursor
; 31 &C787 2 position text cursor (TAB)
;127 &CAAC 0 delete
*************************************************************************
* *
* VDU Variables *
* *
*************************************************************************
;D0 VDU status
;Bit 0 printer output enabled
; 1 scrolling disabled
; 2 paged scrolling enabled
; 3 software scrolling selected
; 4 not used
; 5 printing at graphics cursor enabled
; 6 cursor editing mode enabled
; 7 screen disabled
;D1 byte mask for current graphics point
;D2/3 text colour bytes to be ORed and EORed into memory
;D4/5 graphics colour bytes to be ORed and EORed into memory
;D6/7 address of top line of current graphics cell
;D8/9 address of top scan line of current text character
;DA/F temporary workspace
;E0/1 CRTC row multiplication table pointer
;246 Character definition explosion switch
;248 current video ULA control regiter setting
;249 current pallette setting
;251 flash counter
;252 mark-space count
;253 space period count
;256 EXEC file handle
;257 SPOOL file handle
;260 Econet OSWRCH interception flag
;267 bit 7 set ignore start up message
;268 length of key string
;269 print line counter
;26A number of items in VDU queque
;26B TAB key value
;26C ESCAPE character
;27D cursor editing status
;28F start up options (Keyboard links)
bits 0-2 default screen Mode
3 reverse SHIFT/BREAK
4-5 disc timing parameters
;290 screen display vertical adjustment
;291 interlace toggle flag
;300/1 graphics window left
;302/3 graphics window bottom
;304/5 graphics window right
;306/7 graphics window top
;308 text window left
;309 text window bottom
;30A text window right
;30B text window top
;30C/D graphics origin, horizontal (external values)
;30E/F graphics origin, vertical (external values)
;310/1 current graphics cursor, horizontal (external values)
;312/3 current graphics cursor, vertical (external values)
;314/5 last graphics cursor, horizontal (external values)
;316/7 last graphics cursor, vertical (external values)
;318 text column
;319 text line
;31A graphics scan line expressed as line of character
;31B-323 VDU parameters, last parameter in &323
;324/5 current graphics cursor, horizontal (internal values)
;316/7 current graphics cursor, vertical (internal values)
;328-349 general workspace
;34A/B text cursor address to CRT controller
;34C/D width of text window in bytes
;34E hi byte of address of screen RAM start
;34F bytes per character
;350/1 address of window area start
;352/3 bytes per character row
;354 high byte of screen RAM size
;355 Mode
;356 memory map type
;357/35A current colours
;35B/C graphics plot mode
;35D/E jump vector
;35F last setting of CRT controller Cursor start register
;360 number of logical colours less 1
;361 pixels per byte (0 in text only modes)
;362/3 colour masks
;364/5 X/Y for text input cursor
;366 output cursor character for MODE 7
;367 Font flag
;368/E font location bytes
;36F-37E Colour palette
\ No newline at end of file
diff --git a/docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/C4C0 b/docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/C4C0
new file mode 100644
index 0000000..308e246
--- /dev/null
+++ b/docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/C4C0
@@ -0,0 +1 @@
+BBC Operation System OS 1.20 VDU Main Routines
**************************************************************************
**************************************************************************
** **
** OSWRCH MAIN ROUTINE entry from E0C5 **
** **
** output a byte via the VDU stream **
** **
**************************************************************************
**************************************************************************
;This routine takes up over 40% of the operating system ROM
;entry points are variable, as are the results achieved.
;tracing any particular path is relatively easy but generalising for
;commenting is not. For clarity comments will not be as detailed as
;for later parts of the Operating system.
C4C0 LDX &026A ;get number of items in VDU queue
C4C3 BNE &C512 ;if parameters needed then C512
C4C5 BIT &D0 ;else check status byte
C4C7 BVC &C4D8 ;if cursor editing enabled two cursors exist
C4C9 JSR &C568 ;swap values
C4CC JSR &CD6A ;then set up write cursor
C4CF BMI &C4D8 ;if display disabled C4D8
C4D1 CMP #&0D ;else if character in A=RETURN teminate edit
C4D3 BNE &C4D8 ;else C4D8
C4D5 JSR &D918 ;terminate edit
C4D8 CMP #&7F ;is character DELETE ?
C4DA BEQ &C4ED ;if so C4ED
C4DC CMP #&20 ;is it less than space? (i.e. VDU control code)
C4DE BCC &C4EF ;if so C4EF
C4E0 BIT &D0 ;else check VDU byte ahain
C4E2 BMI &C4EA ;if screen disabled C4EA
C4E4 JSR &CFB7 ;else display a character
C4E7 JSR &C664 ;and cursor right
C4EA JMP &C55E ;
********* read link addresses and number of parameters *****************
C4ED LDA #&20 ;to replace delete character
********* read link addresses and number of parameters *****************
C4EF TAY ;Y=A
C4F0 LDA &C333,Y ;get lo byte of link address
C4F3 STA &035D ;store it in jump vector
C4F6 LDA &C354,Y ;get hi byte
C4F9 BMI &C545 ;if negative (as it will be if a direct address)
;there are no parameters needed
;so C545
C4FB TAX ;else X=A
C4FC ORA #&F0 ;set up negated parameter count
C4FE STA &026A ;store it as number of items in VDU queue
C501 TXA ;get back A
C502 LSR ;A=A/16
C503 LSR ;
C504 LSR ;
C505 LSR ;
C506 CLC ;clear carry
C507 ADC #&C3 ;add &C3 to get hi byte of link address
C509 STA &035E ;
C50C BIT &D0 ;check if cursor editing enabled
C50E BVS &C52F ;if so re-exchange pointers
C510 CLC ;clear carry
C511 RTS ;and exit
;return with carry clear indicates that printer action not required.
;
********** parameters are outstanding ***********************************
X=&26A = 2 complement of number of parameters X=&FF for 1, FE for 2 etc.
C512 STA &0224,X ;store parameter in queue
C515 INX ;increment X
C516 STX &026A ;store it as VDU queue
C519 BNE &C532 ;if not 0 C532 as more parameters are needed
C51B BIT &D0 ;get VDU status byte
C51D BMI &C534 ;if screen disabled C534
C51F BVS &C526 ;else if cursor editing C526
C521 JSR &CCF5 ;execute required function
C524 CLC ;clear carry
C525 RTS ;and exit
;
C526 JSR &C568 ;swap values of cursors
C529 JSR &CD6A ;set up write cursor
C52C JSR &CCF5 ;execute required function
C52F JSR &C565 ;re-exchange pointers
C532 CLC ;carry clear
C533 RTS ;exit
*************************************************************************
* *
* VDU 1 - SEND NEXT CHARACTER TO PRINTER *
* *
* 1 parameter required *
* *
*************************************************************************
;
C534 LDY &035E ;if upper byte of link address not &C5
C537 CPY #&C5 ;printer is not interested
C539 BNE &C532 ;so C532
C53B TAX ;else X=A
C53C LDA &D0 ;A=VDU status byte
C53E LSR ;get bit 0 into carry
C53F BCC &C511 ;if printer not enabled exit
C541 TXA ;restore A
C542 JMP &E11E ;else send byte in A (next byte) to printer
*********** if explicit link address found, no parameters ***************
C545 STA &035E ;upper byte of link address
C548 TYA ;restore A
C549 CMP #&08 ;is it 7 or less?
C54B BCC &C553 ;if so C553
C54D EOR #&FF ;invert it
C54F CMP #&F2 ;c is set if A >&0D
C551 EOR #&FF ;re invert
C553 BIT &D0 ;VDU status byte
C555 BMI &C580 ;if display disabled C580
C557 PHP ;push processor flags
C558 JSR &CCF5 ;execute required function
C55B PLP ;get back flags
C55C BCC &C561 ;if carry clear (from C54B/F)
**************** main exit routine **************************************
C55E LDA &D0 ;VDU status byte
C560 LSR ;Carry is set if printer is enabled
C561 BIT &D0 ;VDU status byte
C563 BVC &C511 ;if no cursor editing C511 to exit
***************** cursor editing routines *******************************
C565 JSR &CD7A ;restore normal write cursor
C568 PHP ;save flags and
C569 PHA ;A
C56A LDX #&18 ;X=&18
C56C LDY #&64 ;Y=&64
C56E JSR &CDDE ;exchange &300/1+X with &300/1+Y
C571 JSR &CF06 ;set up display address
C574 JSR &CA02 ;set cursor position
C577 LDA &D0 ;VDU status byte
C579 EOR #&02 ;invert bit 1 to allow or bar scrolling
C57B STA &D0 ;VDU status byte
C57D PLA ;restore flags and A
C57E PLP ;
C57F RTS ;and exit
;
C580 EOR #&06 ;if A<>6
C582 BNE &C58C ;return via C58C
C584 LDA #&7F ;A=&7F
C586 BCC &C5A8 ;and goto C5A8 ALWAYS!!
******************* check text cursor in use ***************************
C588 LDA &D0 ;VDU status byte
C58A AND #&20 ;set A from bit 5 of status byte
C58C RTS ;and exit
A=0 if text cursor, &20 if graphics
*************************************************************************
* *
* VDU 14 - SET PAGED MODE *
* *
*************************************************************************
;
C58D LDY #&00 ;Y=0
C58F STY &0269 ;paged mode counter
C592 LDA #&04 ;A=04
C594 BNE &C59D ;jump to C59D
*************************************************************************
* *
* VDU 2 - PRINTER ON (START PRINT JOB) *
* *
*************************************************************************
C596 JSR &E1A2 ;select printer buffer and output character
C599 LDA #&94 ;A=&94
;when inverted at C59B this becomes =&01
*************************************************************************
* *
* VDU 21 - DISABLE DISPLAY *
* *
*************************************************************************
C59B EOR #&95 ;if A=&15 A now =&80: if A=&94 A now =1
C59D ORA &D0 ;VDU status byte set bit 0 or bit 7
C59F BNE &C5AA ;branch forward to store
*************************************************************************
* *
* VDU 3 - PRINTER OFF (END PRINT JOB) *
* *
*************************************************************************
C5A1 JSR &E1A2 ;select printer buffer and output character
C5A4 LDA #&0A ;A=10 to clear status bits below...
*************************************************************************
* *
* VDU 15 - PAGED MODE OFF *
* *
*************************************************************************
; A=&F or &A
C5A6 EOR #&F4 ;convert to &FB or &FE
C5A8 AND &D0 ;VDU status byte clear bit 0 or bit 2 of status
C5AA STA &D0 ;VDU status byte
C5AC RTS ;exit
*************************************************************************
* *
* VDU 4 - OUTPUT AT TEXT CURSOR *
* *
*************************************************************************
;
C5AD LDA &0361 ;pixels per byte
C5B0 BEQ &C5AC ;if no graphics in current mode C5AC
C5B2 JSR &C951 ;set CRT controller for text cursor
C5B5 LDA #&DF ;this to clear bit 5 of status byte
C5B7 BNE &C5A8 ;via C5A8 exit
*************************************************************************
* *
* VDU 5 - OUTPUT AT GRAPHICS CURSOR *
* *
*************************************************************************
C5B9 LDA &0361 ;pixels per byte
C5BC BEQ &C5AC ;if none this is text mode so exit
C5BE LDA #&20 ;set up graphics cursor
C5C0 JSR &C954 ;via C954
C5C3 BNE &C59D ;set bit 5 via exit C59D
*************************************************************************
* *
* VDU 8 - CURSOR LEFT *
* *
*************************************************************************
C5C5 JSR &C588 ;A=0 if text cursor A=&20 if graphics cursor
C5C8 BNE &C61F ;move cursor left 8 pixels if graphics
C5CA DEC &0318 ;else decrement text column
C5CD LDX &0318 ;store new text column
C5D0 CPX &0308 ;if it is less than text window left
C5D3 BMI &C5EE ;do wraparound cursor to rt of screen 1 line up
C5D5 LDA &034A ;text cursor 6845 address
C5D8 SEC ;subtract
C5D9 SBC &034F ;bytes per character
C5DC TAX ;put in X
C5DD LDA &034B ;get text cursor 6845 address
C5E0 SBC #&00 ;subtract 0
C5E2 CMP &034E ;compare with hi byte of screen RAM address
C5E5 BCS &C5EA ;if = or greater
C5E7 ADC &0354 ;add screen RAM size hi byte to wrap around
C5EA TAY ;Y=A
C5EB JMP &C9F6 ;Y hi and X lo byte of cursor position
***************** execute wraparound left-up*****************************
C5EE LDA &030A ;text window right
C5F1 STA &0318 ;text column
*************** cursor up ***********************************************
C5F4 DEC &0269 ;paged mode counter
C5F7 BPL &C5FC ;if still greater than 0 skip next instruction
C5F9 INC &0269 ;paged mode counter to restore X=0
C5FC LDX &0319 ;current text line
C5FF CPX &030B ;top of text window
C602 BEQ &C60A ;if its at top of window C60A
C604 DEC &0319 ;else decrement current text line
C607 JMP &C6AF ;and carry on moving cursor
******** cursor at top of window ****************************************
C60A CLC ;clear carry
C60B JSR &CD3F ;check for window violatations
C60E LDA #&08 ;A=8 to check for software scrolling
C610 BIT &D0 ;compare against VDU status byte
C612 BNE &C619 ;if not enabled C619
C614 JSR &C994 ;set screen start register and adjust RAM
C617 BNE &C61C ;jump C61C
C619 JSR &CDA4 ;soft scroll 1 line
C61C JMP &C6AC ;and exit
**********cursor left and down with graphics cursor in use **************
C61F LDX #&00 ;X=0 to select horizontal parameters
********** cursor down with graphics in use *****************************
;X=2 for vertical or 0 for horizontal
C621 STX &DB ;store X
C623 JSR &D10D ;check for window violations
C626 LDX &DB ;restore X
C628 SEC ;set carry
C629 LDA &0324,X ;current graphics cursor X>1=vertical
C62C SBC #&08 ;subtract 8 to move back 1 character
C62E STA &0324,X ;store in current graphics cursor X>1=verticaal
C631 BCS &C636 ;if carry set skip next
C633 DEC &0325,X ;current graphics cursor hi -1
C636 LDA &DA ;&DA=0 if no violation else 1 if vert violation
;2 if horizontal violation
C638 BNE &C658 ;if violation C658
C63A JSR &D10D ;check for window violations
C63D BEQ &C658 ;if none C658
C63F LDX &DB ;else get back X
C641 LDA &0304,X ;graphics window rt X=0 top X=2
C644 CPX #&01 ;is X=0
C646 BCS &C64A ;if not C64A
C648 SBC #&06 ;else subtract 7
C64A STA &0324,X ;current graphics cursor X>1=vertical
C64D LDA &0305,X ;graphics window hi rt X=0 top X=2
C650 SBC #&00 ;subtract carry
C652 STA &0325,X ;current graphics cursor X<2=horizontal else vertical
C655 TXA ;A=X
C656 BEQ &C660 ;cursor up
C658 JMP &D1B8 ;set up external coordinates for graphics
*************************************************************************
* *
* VDU 11 - CURSOR UP *
* *
*************************************************************************
C65B JSR &C588 ;A=0 if text cursor A=&20 if graphics cursor
C65E BEQ &C5F4 ;if text cursor then C5F4
C660 LDX #&02 ;else X=2
C662 BNE &C6B6 ;goto C6B6
*************************************************************************
* *
* VDU 9 - CURSOR RIGHT *
* *
*************************************************************************
C664 LDA &D0 ;VDU status byte
C666 AND #&20 ;check bit 5
C668 BNE &C6B4 ;if set then graphics cursor in use so C6B4
C66A LDX &0318 ;text column
C66D CPX &030A ;text window right
C670 BCS &C684 ;if X exceeds window right then C684
C672 INC &0318 ;text column
C675 LDA &034A ;text cursor 6845 address
C678 ADC &034F ;add bytes per character
C67B TAX ;X=A
C67C LDA &034B ;text cursor 6845 address
C67F ADC #&00 ;add carry if set
C681 JMP &C9F6 ;use X and Y to set new cursor address
********: text cursor down and right *************************************
C684 LDA &0308 ;text window left
C687 STA &0318 ;text column
********: text cursor down *************************************
C68A CLC ;clear carry
C68B JSR &CAE3 ;check bottom margin, X=line count
C68E LDX &0319 ;current text line
C691 CPX &0309 ;bottom margin
C694 BCS &C69B ;if X=>current bottom margin C69B
C696 INC &0319 ;else increment current text line
C699 BCC &C6AF ;
C69B JSR &CD3F ;check for window violations
C69E LDA #&08 ;check bit 3
C6A0 BIT &D0 ;VDU status byte
C6A2 BNE &C6A9 ;if software scrolling enabled C6A9
C6A4 JSR &C9A4 ;perform hardware scroll
C6A7 BNE &C6AC ;
C6A9 JSR &CDFF ;execute upward scroll
C6AC JSR &CEAC ;clear a line
C6AF JSR &CF06 ;set up display address
C6B2 BCC &C732 ;
*********** graphic cursor right ****************************************
C6B4 LDX #&00 ;
************** graphic cursor up (X=2) **********************************
C6B6 STX &DB ;store X
C6B8 JSR &D10D ;check for window violations
C6BB LDX &DB ;get back X
C6BD CLC ;clear carry
C6BE LDA &0324,X ;current graphics cursor X>1=vertical
C6C1 ADC #&08 ;Add 8 pixels
C6C3 STA &0324,X ;current graphics cursor X>1=vertical
C6C6 BCC &C6CB ;
C6C8 INC &0325,X ;current graphics cursor X<2=horizontal else vertical
C6CB LDA &DA ;A=0 no window violations 1 or 2 indicates violation
C6CD BNE &C658 ;if outside window C658
C6CF JSR &D10D ;check for window violations
C6D2 BEQ &C658 ;if no violations C658
C6D4 LDX &DB ;get back X
C6D6 LDA &0300,X ;graphics window X<2 =left else bottom
C6D9 CPX #&01 ;If X=0
C6DB BCC &C6DF ;C6DF
C6DD ADC #&06 ;else add 7
C6DF STA &0324,X ;current graphics cursor X>1=vertical
C6E2 LDA &0301,X ;graphics window hi X<2 =left else bottom
C6E5 ADC #&00 ;add anny carry
C6E7 STA &0325,X ;current graphics cursor X<2=horizontal else vertical
C6EA TXA ;A=X
C6EB BEQ &C6F5 ;if X=0 C6F5 cursor down
C6ED JMP &D1B8 ;set up external coordinates for graphics
*************************************************************************
* *
* VDU 10 - CURSOR DOWN *
* *
*************************************************************************
C6F0 JSR &C588 ;A=0 if text cursor A=&20 if graphics cursor
C6F3 BEQ &C68A ;if text cursor back to C68A
C6F5 LDX #&02 ;else X=2 to indicate vertical movement
C6F7 JMP &C621 ;move graphics cursor down
*************************************************************************
* *
* VDU 28 - DEFINE TEXT WINDOW *
* *
* 4 parameters *
* *
*************************************************************************
;parameters are set up thus
;0320 P1 left margin
;0321 P2 bottom margin
;0322 P3 right margin
;0323 P4 top margin
;Note that last parameter is always in 0323
C6FA LDX &0355 ;screen mode
C6FD LDA &0321 ;get bottom margin
C700 CMP &0323 ;compare with top margin
C703 BCC &C758 ;if bottom margin exceeds top return
C705 CMP &C3E7,X ;text window bottom margin maximum
C708 BEQ &C70C ;if equal then its OK
C70A BCS &C758 ;else exit
C70C LDA &0322 ;get right margin
C70F TAY ;put it in Y
C710 CMP C3EF,X ;text window right hand margin maximum
C713 BEQ &C717 ;if equal then OK
C715 BCS &C758 ;if greater than maximum exit
C717 SEC ;set carry to subtract
C718 SBC &0320 ;left margin
C71B BMI &C758 ;if left greater than right exit
C71D TAY ;else A=Y (window width)
C71E JSR &CA88 ;calculate number of bytes in a line
C721 LDA #&08 ;A=8 to set bit of &D0
C723 JSR &C59D ;indicating that text window is defined
C726 LDX #&20 ;point to parameters
C728 LDY #&08 ;point to text window margins
C72A JSR &D48A ;(&300/3+Y)=(&300/3+X)
C72D JSR &CEE8 ;set up screen address
C730 BCS &C779 ;home cursor within window
C732 JMP &CA02 ;set cursor position
\ No newline at end of file
diff --git a/docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/C735 b/docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/C735
new file mode 100644
index 0000000..badc60f
--- /dev/null
+++ b/docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/C735
@@ -0,0 +1 @@
+*************************************************************************
* *
* OSWORD 9 - READ A PIXEL *
* =POINT(X,Y) *
* *
*************************************************************************
;on entry &EF=A=9
; &F0=X=low byte of parameter block address
; &F1=Y=high byte of parameter block address
; PARAMETER BLOCK
; 0,1=X coordinate
; 2,3=Y coordinate
;on exit, result in BLOCK+4
; =&FF if point was of screen or logical colour of point if on screen
;
C735 LDY #&03 ;Y=3 to point to hi byte of Y coordinate
C737 LDA (&F0),Y ;get it
C739 STA &0328,Y ;store it
C73C DEY ;point to next byte
C73D BPL &C737 ;transfer till Y=&FF lo byte of X coordinate in &328
C73F LDA #&28 ;
C741 JSR &D839 ;check window boundaries
C744 LDY #&04 ;Y=4
C746 BNE &C750 ;jump to C750
*************************************************************************
* *
* OSWORD 11 - READ PALLETTE *
* *
*************************************************************************
;on entry &EF=A=11
; &F0=X=low byte of parameter block address
; &F1=Y=high byte of parameter block address
; PARAMETER BLOCK
; 0=logical colour to read
;on exit, result in BLOCK
; 0=logical colour
; 1=physical colour
; 2=red colour component \
; 3=green colour component } when set using analogue colours
; 4=blue colour component /
C748 AND &0360 ;number of logical colours less 1
C74B TAX ;put it in X
C74C LDA &036F,X ;colour pallette
C74F INY ;increment Y to point to byte 1
C750 STA (&F0),Y ;store data
C752 LDA #&00 ;issue 0s
C754 CPY #&04 ;to next bytes until Y=4
C756 BNE &C74F ;
C758 RTS ;and exit
*************************************************************************
* *
* VDU 12 - CLEAR TEXT SCREEN *
* CLS *
* *
*************************************************************************
;
C759 JSR &C588 ;A=0 if text cursor A=&20 if graphics cursor
C75C BNE &C7BD ;if graphics cursor &C7BD
C75E LDA &D0 ;VDU status byte
C760 AND #&08 ;check if software scrolling (text window set)
C762 BNE &C767 ;if so C767
C764 JMP &CBC1 ;initialise screen display and home cursor
C767 LDX &030B ;top of text window
C76A STX &0319 ;current text line
C76D JSR &CEAC ;clear a line
C770 LDX &0319 ;current text line
C773 CPX &0309 ;bottom margin
C776 INX ;X=X+1
C777 BCC &C76A ;if X at compare is less than bottom margin clear next
*************************************************************************
* *
* VDU 30 - HOME CURSOR *
* *
*************************************************************************
C779 JSR &C588 ;A=0 if text cursor A=&20 if graphics cursor
C77C BEQ &C781 ;if text cursor C781
C77E JMP &CFA6 ;home graphic cursor if graphic
C781 STA &0323 ;store 0 in last two parameters
C784 STA &0322 ;
*************************************************************************
* *
* VDU 31 - POSITION TEXT CURSOR *
* TAB(X,Y) *
* *
* 2 parameters *
* *
*************************************************************************
;0322 = supplied X coordinate
;0323 = supplied Y coordinate
C787 JSR &C588 ;A=0 if text cursor A=&20 if graphics cursor
C78A BNE &C758 ;exit
C78C JSR &C7A8 ;exchange text column/line with workspace 0328/9
C78F CLC ;clear carry
C790 LDA &0322 ;get X coordinate
C793 ADC &0308 ;add to text window left
C796 STA &0318 ;store as text column
C799 LDA &0323 ;get Y coordinate
C79C CLC ;
C79D ADC &030B ;add top of text window
C7A0 STA &0319 ;current text line
C7A3 JSR &CEE8 ;set up screen address
C7A6 BCC &C732 ;set cursor position if C=0 (point on screen)
C7A8 LDX #&18 ;else point to workspace
C7AA LDY #&28 ;and line/column to restore old values
C7AC JMP &CDDE ;exchange &300/1+X with &300/1+Y
*************************************************************************
* *
* VDU 13 - CARRIAGE RETURN *
* *
*************************************************************************
C7AF JSR &C588 ;A=0 if text cursor A=&20 if graphics cursor
C7B2 BEQ &C7B7 ;if text C7B7
C7B4 JMP &CFAD ;else set graphics cursor to left hand columm
C7B7 JSR &CE6E ;set text column to left hand column
C7BA JMP &C6AF ;set up cursor and display address
C7BD JSR &CFA6 ;home graphic cursor
*************************************************************************
* *
* VDU 16 - CLEAR GRAPHICS SCREEN *
* CLG *
* *
*************************************************************************
C7C0 LDA &0361 ;pixels per byte
C7C3 BEQ &C7F8 ;if 0 current mode has no graphics so exit
C7C5 LDX &035A ;Background graphics colour
C7C8 LDY &035C ;background graphics plot mode (GCOL n)
C7CB JSR &D0B3 ;set graphics byte mask in &D4/5
C7CE LDX #&00 ;graphics window
C7D0 LDY #&28 ;workspace
C7D2 JSR &D47C ;set(300/7+Y) from (300/7+X)
C7D5 SEC ;set carry
C7D6 LDA &0306 ;graphics window top lo.
C7D9 SBC &0302 ;graphics window bottom lo
C7DC TAY ;Y=difference
C7DD INY ;increment
C7DE STY &0330 ;and store in workspace (this is line count)
C7E1 LDX #&2C ;
C7E3 LDY #&28 ;
C7E5 JSR &D6A6 ;clear line
C7E8 LDA &032E ;decrement window height in pixels
C7EB BNE &C7F0 ;
C7ED DEC &032F ;
C7F0 DEC &032E ;
C7F3 DEC &0330 ;decrement line count
C7F6 BNE &C7E1 ;if <>0 then do it again
C7F8 RTS ;exit
*************************************************************************
* *
* VDU 17 - DEFINE TEXT COLOUR *
* COLOUR n *
* *
* 1 parameter *
* *
*************************************************************************
;parameter in &0323
C7F9 LDY #&00 ;Y=0
C7FB BEQ &C7FF ;jump to C7FF
*************************************************************************
* *
* VDU 18 - DEFINE GRAPHICS COLOUR *
* GCOL k,c *
* *
* 2 parameters *
* *
*************************************************************************
;parameters in 323,322
C7FD LDY #&02 ;Y=2
C7FF LDA &0323 ;get last parameter
C802 BPL &C805 ;if +ve it's foreground colour so C805
C804 INY ;else Y=Y+1
C805 AND &0360 ;number of logical colours less 1
C808 STA &DA ;store it
C80A LDA &0360 ;number of logical colours less 1
C80D BEQ &C82B ;if none exit
C80F AND #&07 ;else limit to an available colour and clear M
C811 CLC ;clear carry
C812 ADC &DA ;Add last parameter to get pointer to table
C814 TAX ;pointer into X
C815 LDA &C423,X ;get plot options from table
C818 STA &0357,Y ; colour Y=0=text fgnd 1= text bkgnd 2=graphics fg etc
C81B CPY #&02 ;If Y>1
C81D BCS &C82C ;then its graphics so C82C else
C81F LDA &0357 ;foreground text colour
C822 EOR #&FF ;invert
C824 STA &D3 ;text colour byte to be orred or EORed into memory
C826 EOR &0358 ;background text colour
C829 STA &D2 ;text colour byte to be orred or EORed into memory
C82B RTS ;and exit
;
C82C LDA &0322 ;get first parameter
C82F STA &0359,Y ;text colour Y=0=foreground 1=background etc.
C832 RTS ;exit
;
C833 LDA #&20 ;
C835 STA &0358 ;background text colour
C838 RTS ;
*************************************************************************
* *
* VDU 20 - RESTORE DEFAULT COLOURS *
* *
*************************************************************************
;
C839 LDX #&05 ;X=5
C83B LDA #&00 ;A=0
C83D STA &0357,X ;zero all colours
C840 DEX ;
C841 BPL &C83D ;until X=&FF
C843 LDX &0360 ;number of logical colours less 1
C846 BEQ &C833 ;if none its MODE 7 so C833
C848 LDA #&FF ;A=&FF
C84A CPX #&0F ;if not mode 2 (16 colours)
C84C BNE &C850 ;goto C850
C84E LDA #&3F ;else A=&3F
C850 STA &0357 ;foreground text colour
C853 STA &0359 ;foreground graphics colour
C856 EOR #&FF ;invert A
C858 STA &D2 ;text colour byte to be orred or EORed into memory
C85A STA &D3 ;text colour byte to be orred or EORed into memory
C85C STX &031F ;set first parameter of 5
C85F CPX #&03 ;if there are 4 colours
C861 BEQ &C874 ;goto C874
C863 BCC &C885 ;if less there are 2 colours goto C885
;else there are 16 colours
C865 STX &0320 ;set second parameter
C868 JSR &C892 ;do VDU 19 etc
C86B DEC &0320 ;decrement first parameter
C86E DEC &031F ;and last parameter
C871 BPL &C868 ;
C873 RTS ;
;
********* 4 colour mode *************************************************
C874 LDX #&07 ;X=7
C876 STX &0320 ;set first parameter
C879 JSR &C892 ;and do VDU 19
C87C LSR &0320 ;
C87F DEC &031F ;
C882 BPL &C879 ;
C884 RTS ;exit
;********* 2 colour mode ************************************************
C885 LDX #&07 ;X=7
C887 JSR &C88F ;execute VDU 19
C88A LDX #&00 ;X=0
C88C STX &031F ;store it as
C88F STX &0320 ;both parameters
*************************************************************************
* *
* VDU 19 - DEFINE COLOURS *
* [COLOUR l,p] *
* [COLOUR l,r,g,b] *
* *
* 5 parameters *
* *
*************************************************************************
;&31F=first parameter logical colour
;&320=second physical colour
C892 PHP ;push processor flags
C893 SEI ;disable interrupts
C894 LDA &031F ;get first parameter and
C897 AND &0360 ;number of logical colours less 1
C89A TAX ;toi make legal X=A
C89B LDA &0320 ;A=second parameter
C89E AND #&0F ;make legal
C8A0 STA &036F,X ;colour pallette
C8A3 TAY ;Y=A
C8A4 LDA &0360 ;number of logical colours less 1
C8A7 STA &FA ;store it
C8A9 CMP #&03 ;is it 4 colour mode??
C8AB PHP ;save flags
C8AC TXA ;A=X
C8AD ROR ;rotate A into &FA
C8AE ROR &FA ;
C8B0 BCS &C8AD ;
C8B2 ASL &FA ;
C8B4 TYA ;A=Y
C8B5 ORA &FA ;
C8B7 TAX ;
C8B8 LDY #&00 ;Y=0
C8BA PLP ;check flags
C8BB PHP ;
C8BC BNE &C8CC ;if A<>3 earlier C8CC
C8BE AND #&60 ;else A=&60 to test bits 5 and 6
C8C0 BEQ &C8CB ;if not set C8CB
C8C2 CMP #&60 ;else if both set
C8C4 BEQ &C8CB ;C8CB
C8C6 TXA ;A=X
C8C7 EOR #&60 ;invert
C8C9 BNE &C8CC ;and if not 0 C8CC
C8CB TXA ;X=A
C8CC JSR &EA11 ;call Osbyte 155 pass data to pallette register
C8CF TYA ;
C8D0 SEC ;
C8D1 ADC &0360 ;number of logical colours less 1
C8D4 TAY ;
C8D5 TXA ;
C8D6 ADC #&10 ;
C8D8 TAX ;
C8D9 CPY #&10 ;if Y<16 do it again
C8DB BCC &C8BA ;
C8DD PLP ;pull flags twice
C8DE PLP ;
C8DF RTS ;and exit
*************************************************************************
* *
* OSWORD 12 - WRITE PALLETTE *
* *
*************************************************************************
;on entry X=&F0:Y=&F1:YX points to parameter block
;byte 0 = logical colour; byte 1 physical colour; bytes 2-4=0
C8E0 PHP ;push flags
C8E1 AND &0360 ;and with number of logical colours less 1
C8E4 TAX ;X=A
C8E5 INY ;Y=Y+1
C8E6 LDA (&F0),Y ;get phsical colour
C8E8 JMP &C89E ;do VDU19 with parameters in X and A
*************************************************************************
* *
* VDU 22 - SELECT MODE *
* MODE n *
* *
* 1 parameter *
* *
*************************************************************************
;parameter in &323
C8EB LDA &0323 ;get parameter
C8EE JMP &CB33 ;goto CB33
*************************************************************************
* *
* VDU 23 - DEFINE CHARACTERS *
* *
* 9 parameters *
* *
*************************************************************************
;parameters are:-
;31B character to define
;31C to 323 definition
C8F1 LDA &031B ;get character to define
C8F4 CMP #&20 ;is it ' '
C8F6 BCC &C93F ;if less then it is a control instruction, goto C93F
C8F8 PHA ;else save parameter
C8F9 LSR ;A=A/32
C8FA LSR ;
C8FB LSR ;
C8FC LSR ;
C8FD LSR ;
C8FE TAX ;X=A
C8FF LDA &C40D,X ;get font flag mask from table (A=&80/2^X)
C902 BIT &0367 ;font flag
C905 BNE &C927 ;and if A<>0 C927 storage area is established already
C907 ORA &0367 ;or with font flag to set bit found to be 0
C90A STA &0367 ;font flag
C90D TXA ;get back A
C90E AND #&03 ;And 3 to clear all but bits 0 and 1
C910 CLC ;clear carry
C911 ADC #&BF ;add &BF (A=&C0,&C1,&C2) to select a character page
C913 STA &DF ;store it
C915 LDA &0367,X ;get font location byte (normally &0C)
C918 STA &DD ;store it
C91A LDY #&00 ;Y=0 so (&DE) holds (&C000 -&C2FF)
C91C STY &DC ;
C91E STY &DE ;
C920 LDA (&DE),Y ;transfer page to storage area
C922 STA (&DC),Y ;
C924 DEY ;
C925 BNE &C920 ;
C927 PLA ;get back A
C928 JSR &D03E ;set up character definition pointers
C92B LDY #&07 ;Y=7
C92D LDA &031C,Y ;transfer definition parameters
C930 STA (&DE),Y ;to RAM definition
C932 DEY ;
C933 BPL &C92D ;
C935 RTS ;and exit
;
C936 PLA ;Pull A
C937 RTS ;and exit
;
************ VDU EXTENSION **********************************************
C938 LDA &031F ;A=fifth VDU parameter
C93B CLC ;clear carry
C93C JMP (&0226) ;jump via VDUV vector
********** VDU control commands *****************************************
C93F CMP #&01 ;is A=1
C941 BCC &C958 ;if less (0) then set CRT register directly
C943 BNE &C93C ;if not 1 jump to VDUV for VDU extension
********** turn cursor on/off *******************************************
C945 JSR &C588 ;A=0 if text cursor, A=&20 if graphics cursor
C948 BNE &C937 ;if graphics exit
C94A LDA #&20 ;A=&20 - preload to turn cursor off
C94C LDY &031C ;Y=second VDU parameter
C94F BEQ &C954 ;if 0, jump to C954 to turn cursor off
C951 LDA &035F ;get last setting of CRT controller register
;for cursor on
C954 LDY #&0A ;Y=10 - cursor control register number
C956 BNE &C985 ;jump to C985, Y=register, Y=value
********** set CRT controller *******************************************
C958 LDA &031D ;get third
C95B LDY &031C ;and second parameter
C95E CPY #&07 ;is Y=7
C960 BCC &C985 ;if less C985
C962 BNE &C967 ;else if >7 C967
C964 ADC &0290 ;else ADD screen vertical display adjustment
C967 CPY #&08 ;If Y<>8
C969 BNE &C972 ;C972
C96B ORA #&00 ;if bit 7 set
C96D BMI &C972 ;C972
C96F EOR &0291 ;else EOR with interlace toggle
C972 CPY #&0A ;Y=10??
C974 BNE &C985 ;if not C985
C976 STA &035F ;last setting of CRT controller register
C979 TAY ;Y=A
C97A LDA &D0 ;VDU status byte
C97C AND #&20 ;check bit 5 printing at graphics cursor??
C97E PHP ;push flags
C97F TYA ;Y=A
C980 LDY #&0A ;Y=10
C982 PLP ;pull flags
C983 BNE &C98B ;if graphics in use then C98B
C985 STY &FE00 ;else set CRTC address register
C988 STA &FE01 ;and poke new value to register Y
C98B RTS ;exit
*************************************************************************
* *
* VDU 25 - PLOT *
* PLOT k,x,y *
* *
* 5 parameters *
* *
*************************************************************************
;
C98C LDX &0361 ;pixels per byte
C98F BEQ &C938 ;if no graphics available go to VDU Extension
C991 JMP &D060 ;else enter Plot routine at D060
********** adjust screen RAM addresses **********************************
C994 LDX &0350 ;window area start address lo
C997 LDA &0351 ;window area start address hi
C99A JSR &CCF8 ;subtract bytes per character row from this
C99D BCS &C9B3 ;if no wraparound needed C9B3
C99F ADC &0354 ;screen RAM size hi byte to wrap around
C9A2 BCC &C9B3 ;
C9A4 LDX &0350 ;window area start address lo
C9A7 LDA &0351 ;window area start address hi
C9AA JSR &CAD4 ;add bytes per char. row
C9AD BPL &C9B3 ;
C9AF SEC ;wrap around i other direction
C9B0 SBC &0354 ;screen RAM size hi byte
C9B3 STA &0351 ;window area start address hi
C9B6 STX &0350 ;window area start address lo
C9B9 LDY #&0C ;Y=12
C9BB BNE &CA0E ;jump to CA0E
*************************************************************************
* *
* VDU 26 - SET DEFAULT WINDOWS *
* *
*************************************************************************
C9BD LDA #&00 ;A=0
C9BF LDX #&2C ;X=&2C
C9C1 STA &0300,X ;clear all windows
C9C4 DEX ;
C9C5 BPL &C9C1 ;until X=&FF
C9C7 LDX &0355 ;screen mode
C9CA LDY C3EF,X ;text window right hand margin maximum
C9CD STY &030A ;text window right
C9D0 JSR &CA88 ;calculate number of bytes in a line
C9D3 LDY &C3E7,X ;text window bottom margin maximum
C9D6 STY &0309 ;bottom margin
C9D9 LDY #&03 ;Y=3
C9DB STY &0323 ;set as last parameter
C9DE INY ;increment Y
C9DF STY &0321 ;set parameters
C9E2 DEC &0322 ;
C9E5 DEC &0320 ;
C9E8 JSR &CA39 ;and do VDU 24
C9EB LDA #&F7 ;
C9ED JSR &C5A8 ;clear bit 3 of &D0
C9F0 LDX &0350 ;window area start address lo
C9F3 LDA &0351 ;window area start address hi
C9F6 STX &034A ;text cursor 6845 address
C9F9 STA &034B ;text cursor 6845 address
C9FC BPL &CA02 ;set cursor position
C9FE SEC ;
C9FF SBC &0354 ;screen RAM size hi byte
**************** set cursor position ************************************
CA02 STX &D8 ;set &D8/9 from X/A
CA04 STA &D9 ;
CA06 LDX &034A ;text cursor 6845 address
CA09 LDA &034B ;text cursor 6845 address
CA0C LDY #&0E ;Y=15
CA0E PHA ;Push A
CA0F LDA &0355 ;screen mode
CA12 CMP #&07 ;is it mode 7?
CA14 PLA ;get back A
CA15 BCS &CA27 ;if mode 7 selected CA27
CA17 STX &DA ;else store X
CA19 LSR ;divide X/A by 8
CA1A ROR &DA ;
CA1C LSR ;
CA1D ROR &DA ;
CA1F LSR ;
CA20 ROR &DA ;
CA22 LDX &DA ;
CA24 JMP &CA2B ;goto CA2B
CA27 SBC #&74 ;mode 7 subtract &74
CA29 EOR #&20 ;EOR with &20
CA2B STY &FE00 ;write to CRTC address file register
CA2E STA &FE01 ;and to relevant address (register 14)
CA31 INY ;Increment Y
CA32 STY &FE00 ;write to CRTC address file register
CA35 STX &FE01 ;and to relevant address (register 15)
CA38 RTS ;and RETURN
\ No newline at end of file
diff --git a/docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/CA39 b/docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/CA39
new file mode 100644
index 0000000..576492f
--- /dev/null
+++ b/docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/CA39
@@ -0,0 +1 @@
+*************************************************************************
* *
* VDU 24 - DEFINE GRAPHICS WINDOW *
* *
* 8 parameters *
* *
*************************************************************************
;&31C/D Left margin
;&31E/F Bottom margin
;&320/1 Right margin
;&322/3 Top margin
CA39 JSR &CA81 ;exchange 310/3 with 328/3
CA3C LDX #&1C ;
CA3E LDY #&2C ;
CA40 JSR &D411 ;calculate width=right - left
; height = top-bottom
CA43 ORA &032D ;
CA46 BMI &CA81 ;exchange 310/3 with 328/3 and exit
CA48 LDX #&20 ;X=&20
CA4A JSR &D149 ;scale pointers to mode
CA4D LDX #&1C ;X=&1C
CA4F JSR &D149 ;scale pointers to mode
CA52 LDA &031F ;check for negative margins
CA55 ORA &031D ;
CA58 BMI &CA81 ;if found exchange 310/3 with 328/3 and exit
CA5A LDA &0323 ;
CA5D BNE &CA81 ;exchange 310/3 with 328/3 and exit
CA5F LDX &0355 ;screen mode
CA62 LDA &0321 ;right margin hi
CA65 STA &DA ;store it
CA67 LDA &0320 ;right margin lo
CA6A LSR &DA ;/2
CA6C ROR ;A=A/2
CA6D LSR &DA ;/2
CA6F BNE &CA81 ;exchange 310/3 with 328/3
CA71 ROR ;A=A/2
CA72 LSR ;A=A/2
CA73 CMP C3EF,X ;text window right hand margin maximum
CA76 BEQ &CA7A ;if equal CA7A
CA78 BPL &CA81 ;exchange 310/3 with 328/3
CA7A LDY #&00 ;Y=0
CA7C LDX #&1C ;X=&1C
CA7E JSR &D47C ;set(300/7+Y) from (300/7+X)
***************** exchange 310/3 with 328/3 *****************************
CA81 LDX #&10 ;X=10
CA83 LDY #&28 ;Y=&28
CA85 JMP &CDE6 ;exchange 300/3+Y and 300/3+X
CA88 INY ;Y=Y+1
CA89 TYA ;A=Y
CA8A LDY #&00 ;Y=0
CA8C STY &034D ;text window width hi (bytes)
CA8F STA &034C ;text window width lo (bytes)
CA92 LDA &034F ;bytes per character
CA95 LSR ;/2
CA96 BEQ &CAA1 ;if 0 exit
CA98 ASL &034C ;text window width lo (bytes)
CA9B ROL &034D ;text window width hi (bytes)
CA9E LSR ;/2
CA9F BCC &CA98 ;
CAA1 RTS ;
*************************************************************************
* *
* VDU 29 - SET GRAPHICS ORIGIN *
* *
* 4 parameters *
* *
*************************************************************************
;
CAA2 LDX #&20 ;
CAA4 LDY #&0C ;
CAA6 JSR &D48A ;(&300/3+Y)=(&300/3+X)
CAA9 JMP &D1B8 ;set up external coordinates for graphics
*************************************************************************
* *
* VDU 127 (&7F) - DELETE (entry 32) *
* *
*************************************************************************
CAAC JSR &C5C5 ;cursor left
CAAF JSR &C588 ;A=0 if text cursor A=&20 if graphics cursor
CAB2 BNE &CAC7 ;if graphics then CAC7
CAB4 LDX &0360 ;number of logical colours less 1
CAB7 BEQ &CAC2 ;if mode 7 CAC2
CAB9 STA &DE ;else store A (always 0)
CABB LDA #&C0 ;A=&C0
CABD STA &DF ;store in &DF (&DE) now points to C300 SPACE pattern
CABF JMP &CFBF ;display a space
CAC2 LDA #&20 ;A=&20
CAC4 JMP &CFDC ;and return to display a space
CAC7 LDA #&7F ;for graphics cursor
CAC9 JSR &D03E ;set up character definition pointers
CACC LDX &035A ;Background graphics colour
CACF LDY #&00 ;Y=0
CAD1 JMP &CF63 ;invert pattern data (to background colour)
***** Add number of bytes in a line to X/A ******************************
CAD4 PHA ;store A
CAD5 TXA ;A=X
CAD6 CLC ;clear carry
CAD7 ADC &0352 ;bytes per character row
CADA TAX ;X=A
CADB PLA ;get back A
CADC ADC &0353 ;bytes per character row
CADF RTS ;and return
;
********* control scrolling in paged mode *******************************
CAE0 JSR &CB14 ;zero paged mode line counter
CAE3 JSR &E9D9 ;osbyte 118 check keyboard status; set LEDs
CAE6 BCC &CAEA ;if carry clear CAEA
CAE8 BMI &CAE0 ;if M set CAE0 do it again
CAEA LDA &D0 ;VDU status byte
CAEC EOR #&04 ;invert bit 2 paged scrolling
CAEE AND #&46 ;and if 2 cursors, paged mode off, or scrolling
CAF0 BNE &CB1C ;barred then CB1C to exit
CAF2 LDA &0269 ;paged mode counter
CAF5 BMI &CB19 ;if negative then exit via CB19
CAF7 LDA &0319 ;current text line
CAFA CMP &0309 ;bottom margin
CAFD BCC &CB19 ;increment line counter and exit
CAFF LSR ;A=A/4
CB00 LSR ;
CB01 SEC ;set carry
CB02 ADC &0269 ;paged mode counter
CB05 ADC &030B ;top of text window
CB08 CMP &0309 ;bottom margin
CB0B BCC &CB19 ;increment line counter and exit
CB0D CLC ;clear carry
CB0E JSR &E9D9 ;osbyte 118 check keyboard status; set LEDs
CB11 SEC ;set carry
CB12 BPL &CB0E ;if +ve result then loop till shift pressed
**************** zero paged mode counter *******************************
CB14 LDA #&FF ;
CB16 STA &0269 ;paged mode counter
CB19 INC &0269 ;paged mode counter
CB1C RTS ;
;
*********part of intitialisation routines ******************************
CB1D PHA ;save A
CB1E LDX #&7F ;X=&7F
CB20 LDA #&00 ;A=0
CB22 STA &D0 ;VDU status byte to set default conditions
CB24 STA &02FF,X ;zero 300,37E
CB27 DEX ;with this loop
CB28 BNE &CB24 ;
CB2A JSR &CD07 ;implode character definitions
CB2D PLA ;get back A
CB2E LDX #&7F ;X=&7F
CB30 STX &0366 ;mode 7 write cursor character
CB33 BIT &028E ;available RAM pages
CB36 BMI &CB3A ;if 32k CB3A
CB38 ORA #&04 ;ensure only modes 4-7 are available
CB3A AND #&07 ;X=A and 7 ensure legal mode
CB3C TAX ;X=mode
CB3D STX &0355 ;set screen mode flag
CB40 LDA &C414,X ;no. of colours -1 in mode table
CB43 STA &0360 ;number of logical colours less 1
CB46 LDA &C3FF,X ;number of bytes /character for each mode
CB49 STA &034F ;bytes per character
CB4C LDA &C43A,X ;display mode pixels/byte table
CB4F STA &0361 ;pixels per byte
CB52 BNE &CB56 ;if <> 0 CB56
CB54 LDA #&07 ;else A=7
CB56 ASL ;A=A*2
CB57 TAY ;Y=A
CB58 LDA &C406,Y ;mask table
CB5B STA &0363 ;colour mask left
CB5E ASL ;A=A*2
CB5F BPL &CB5E ;If still +ve CB5E
CB61 STA &0362 ;colour mask right
CB64 LDY &C440,X ;screen display memory index table
CB67 STY &0356 ;memory map type
CB6A LDA &C44F,Y ;VDU section control
CB6D JSR &E9F8 ;set hardware scrolling to VIA
CB70 LDA &C44B,Y ;VDU section control
CB73 JSR &E9F8 ;set hardware scrolling to VIA
CB76 LDA &C459,Y ;Screen RAM size hi byte table
CB79 STA &0354 ;screen RAM size hi byte
CB7C LDA &C45E,Y ;screen ram address hi byte
CB7F STA &034E ;hi byte of screen RAM address
CB82 TYA ;Y=A
CB83 ADC #&02 ;Add 2
CB85 EOR #&07 ;
CB87 LSR ;/2
CB88 TAX ;X=A
CB89 LDA &C466,X ;row multiplication table pointer
CB8C STA &E0 ;store it
CB8E LDA #&C3 ;A=&C3
CB90 STA &E1 ;store it (&E0) now points to C3B5 or C375
CB92 LDA &C463,X ;get nuber of bytes per row from table
CB95 STA &0352 ;store as bytes per character row
CB98 STX &0353 ;bytes per character row
CB9B LDA #&43 ;A=&43
CB9D JSR &C5A8 ;A=A and &D0:&D0=A
CBA0 LDX &0355 ;screen mode
CBA3 LDA &C3F7,X ;get video ULA control setting
CBA6 JSR &EA00 ;set video ULA using osbyte 154
CBA9 PHP ;push flags
CBAA SEI ;set interrupts
CBAB LDX &C469,Y ;get cursor end register data from table
CBAE LDY #&0B ;Y=11
CBB0 LDA &C46E,X ;get end of 6845 registers 0-11 table
CBB3 JSR &C95E ;set register Y
CBB6 DEX ;reduce pointers
CBB7 DEY ;
CBB8 BPL &CBB0 ;and if still >0 do it again
CBBA PLP ;pull flags
CBBB JSR &C839 ;set default colours
CBBE JSR &C9BD ;set default windows
CBC1 LDX #&00 ;X=0
CBC3 LDA &034E ;hi byte of screen RAM address
CBC6 STX &0350 ;window area start address lo
CBC9 STA &0351 ;window area start address hi
CBCC JSR &C9F6 ;use X and Y to set new cursor address
CBCF LDY #&0C ;Y=12
CBD1 JSR &CA2B ;set registers 12 and 13 in CRTC
CBD4 LDA &0358 ;background text colour
CBD7 LDX &0356 ;memory map type
CBDA LDY &C454,X ;get section control number
CBDD STY &035D ;set it in jump vector lo
CBE0 LDY #&CC ;Y=&CC
CBE2 STY &035E ;upper byte of link address
CBE5 LDX #&00 ;X=0
CBE7 STX &0269 ;paged mode counter
CBEA STX &0318 ;text column
CBED STX &0319 ;current text line
CBF0 JMP (&035D) ;jump vector set up previously
*************************************************************************
* *
* OSWORD 10 - READ CHARACTER DEFINITION *
* *
*************************************************************************
;&EF=A:&F0=X:&F1=Y, on entry YX contains number of byte to be read
;(&DE) points to address
;on exit byte YX+1 to YX+8 contain definition
CBF3 JSR &D03E ;set up character definition pointers
CBF6 LDY #&00 ;Y=0
CBF8 LDA (&DE),Y ;get first byte
CBFA INY ;Y=Y+1
CBFB STA (&F0),Y ;store it in YX
CBFD CPY #&08 ;until Y=8
CBFF BNE &CBF8 ;
CC01 RTS ;then exit
;
*************************************************************************
* *
* MAIN SCREEN CLEARANCE ROUTINE *
* *
*************************************************************************
;on entry A contains background colour which is set in every byte
;of the screen
************************ Mode 0,1,2 entry point *************************
CC02 STA &3000,X ;
CC05 STA &3100,X ;
CC08 STA &3200,X ;
CC0B STA &3300,X ;
CC0E STA &3400,X ;
CC11 STA &3500,X ;
CC14 STA &3600,X ;
CC17 STA &3700,X ;
CC1A STA &3800,X ;
CC1D STA &3900,X ;
CC20 STA &3A00,X ;
CC23 STA &3B00,X ;
CC26 STA &3C00,X ;
CC29 STA &3D00,X ;
CC2C STA &3E00,X ;
CC2F STA &3F00,X ;
************************ Mode 3 entry point *****************************
CC32 STA &4000,X ;
CC35 STA &4100,X ;
CC38 STA &4200,X ;
CC3B STA &4300,X ;
CC3E STA &4400,X ;
CC41 STA &4500,X ;
CC44 STA &4600,X ;
CC47 STA &4700,X ;
CC4A STA &4800,X ;
CC4D STA &4900,X ;
CC50 STA &4A00,X ;
CC53 STA &4B00,X ;
CC56 STA &4C00,X ;
CC59 STA &4D00,X ;
CC5C STA &4E00,X ;
CC5F STA &4F00,X ;
CC62 STA &5000,X ;
CC65 STA &5100,X ;
CC68 STA &5200,X ;
CC6B STA &5300,X ;
CC6E STA &5400,X ;
CC71 STA &5500,X ;
CC74 STA &5600,X ;
CC77 STA &5700,X ;
************************ Mode 4,5 entry point ***************************
CC7A STA &5800,X ;
CC7D STA &5900,X ;
CC80 STA &5A00,X ;
CC83 STA &5B00,X ;
CC86 STA &5C00,X ;
CC89 STA &5D00,X ;
CC8C STA &5E00,X ;
CC8F STA &5F00,X ;
************************ Mode 6 entry point *****************************
CC92 STA &6000,X ;
CC95 STA &6100,X ;
CC98 STA &6200,X ;
CC9B STA &6300,X ;
CC9E STA &6400,X ;
CCA1 STA &6500,X ;
CCA4 STA &6600,X ;
CCA7 STA &6700,X ;
CCAA STA &6800,X ;
CCAD STA &6900,X ;
CCB0 STA &6A00,X ;
CCB3 STA &6B00,X ;
CCB6 STA &6C00,X ;
CCB9 STA &6D00,X ;
CCBC STA &6E00,X ;
CCBF STA &6F00,X ;
CCC2 STA &7000,X ;
CCC5 STA &7100,X ;
CCC8 STA &7200,X ;
CCCB STA &7300,X ;
CCCE STA &7400,X ;
CCD1 STA &7500,X ;
CCD4 STA &7600,X ;
CCD7 STA &7700,X ;
CCDA STA &7800,X ;
CCDD STA &7900,X ;
CCE0 STA &7A00,X ;
CCE3 STA &7B00,X ;
************************ Mode 7 entry point *****************************
CCE6 STA &7C00,X ;
CCE9 STA &7D00,X ;
CCEC STA &7E00,X ;
CCEF STA &7F00,X ;
CCF2 INX ;
CCF3 BEQ &CD65 ;exit
****************** execute required function ****************************
CCF5 JMP (&035D) ;jump vector set up previously
********* subtract bytes per line from X/A ******************************
CCF8 PHA ;Push A
CCF9 TXA ;A=X
CCFA SEC ;set carry for subtraction
CCFB SBC &0352 ;bytes per character row
CCFE TAX ;restore X
CCFF PLA ;and A
CD00 SBC &0353 ;bytes per character row
CD03 CMP &034E ;hi byte of screen RAM address
CD06 RTS ;return
*************************************************************************
* *
* OSBYTE 20 - EXPLODE CHARACTERS *
* *
*************************************************************************
;
CD07 LDA #&0F ;A=15
CD09 STA &0367 ;font flag indicating that page &0C,&C0-&C2 are
;used for user defined characters
CD0C LDA #&0C ;A=&0C
CD0E LDY #&06 ;set loop counter
CD10 STA &0368,Y ;set all font location bytes
CD13 DEY ;to page &0C to indicate only page available
CD14 BPL &CD10 ;for user character definitions
CD16 CPX #&07 ;is X= 7 or greater
CD18 BCC &CD1C ;if not CD1C
CD1A LDX #&06 ;else X=6
CD1C STX &0246 ;character definition explosion switch
CD1F LDA &0243 ;A=primary OSHWM
CD22 LDX #&00 ;X=0
CD24 CPX &0246 ;character definition explosion switch
CD27 BCS &CD34 ;
CD29 LDY &C4BA,X ;get soft character RAM allocation
CD2C STA &0368,Y ;font location bytes
CD2F ADC #&01 ;Add 1
CD31 INX ;X=X+1
CD32 BNE &CD24 ;if X<>0 then CD24
CD34 STA &0244 ;current value of page (OSHWM)
CD37 TAY ;Y=A
CD38 BEQ &CD06 ;return via CD06 (ERROR?)
CD3A LDX #&11 ;X=&11
CD3C JMP &F168 ;issue paged ROM service call &11
;font implosion/explosion warning
******** move text cursor to next line **********************************
CD3F LDA #&02 ;A=2 to check if scrolling disabled
CD41 BIT &D0 ;VDU status byte
CD43 BNE &CD47 ;if scrolling is barred CD47
CD45 BVC &CD79 ;if cursor editing mode disabled RETURN
CD47 LDA &0309 ;bottom margin
CD4A BCC &CD4F ;if carry clear on entry CD4F
CD4C LDA &030B ;else if carry set get top of text window
CD4F BVS &CD59 ;and if cursor editing enabled CD59
CD51 STA &0319 ;get current text line
CD54 PLA ;pull return link from stack
CD55 PLA ;
CD56 JMP &C6AF ;set up cursor and display address
CD59 PHP ;push flags
CD5A CMP &0365 ;Y coordinate of text input cursor
CD5D BEQ &CD78 ;if A=line count of text input cursor CD78 to exit
CD5F PLP ;get back flags
CD60 BCC &CD66 ;
CD62 DEC &0365 ;Y coordinate of text input cursor
CD65 RTS ;exit
;
CD66 INC &0365 ;Y coordinate of text input cursor
CD69 RTS ;exit
*********************** set up write cursor ********************************
CD6A PHP ;save flags
CD6B PHA ;save A
CD6C LDY &034F ;bytes per character
CD6F DEY ;Y=Y-1
CD70 BNE &CD8F ;if Y=0 Mode 7 is in use
CD72 LDA &0338 ;so get mode 7 write character cursor character &7F
CD75 STA (&D8),Y ;store it at top scan line of current character
CD77 PLA ;pull A
CD78 PLP ;pull flags
CD79 RTS ;and exit
;
CD7A PHP ;push flags
CD7B PHA ;push A
CD7C LDY &034F ;bytes per character
CD7F DEY ;
CD80 BNE &CD8F ;if not mode 7
CD82 LDA (&D8),Y ;get cursor from top scan line
CD84 STA &0338 ;store it
CD87 LDA &0366 ;mode 7 write cursor character
CD8A STA (&D8),Y ;store it at scan line
CD8C JMP &CD77 ;and exit
CD8F LDA #&FF ;A=&FF =cursor
CD91 CPY #&1F ;except in mode 2 (Y=&1F)
CD93 BNE &CD97 ;if not CD97
CD95 LDA #&3F ;load cursor byte mask
********** produce white block write cursor *****************************
CD97 STA &DA ;store it
CD99 LDA (&D8),Y ;get scan line byte
CD9B EOR &DA ;invert it
CD9D STA (&D8),Y ;store it on scan line
CD9F DEY ;decrement scan line counter
CDA0 BPL &CD99 ;do it again
CDA2 BMI &CD77 ;then jump to &CD77
CDA4 JSR &CE5B ;exchange line and column cursors with workspace copies
CDA7 LDA &0309 ;bottom margin
CDAA STA &0319 ;current text line
CDAD JSR &CF06 ;set up display address
CDB0 JSR &CCF8 ;subtract bytes per character row from this
CDB3 BCS &CDB8 ;wraparound if necessary
CDB5 ADC &0354 ;screen RAM size hi byte
CDB8 STA &DB ;store A
CDBA STX &DA ;X
CDBC STA &DC ;A again
CDBE BCS &CDC6 ;if C set there was no wraparound so CDC6
CDC0 JSR &CE73 ;copy line to new position
;using (&DA) for read
;and (&D8) for write
CDC3 JMP &CDCE ;
CDC6 JSR &CCF8 ;subtract bytes per character row from X/A
CDC9 BCC &CDC0 ;if a result is outside screen RAM CDC0
CDCB JSR &CE38 ;perform a copy
CDCE LDA &DC ;set write pointer from read pointer
CDD0 LDX &DA ;
CDD2 STA &D9 ;
CDD4 STX &D8 ;
CDD6 DEC &DE ;decrement window height
CDD8 BNE &CDB0 ;and if not zero CDB0
CDDA LDX #&28 ;point to workspace
CDDC LDY #&18 ;point to text column/line
CDDE LDA #&02 ;number of bytes to swap
CDE0 BNE &CDE8 ;exchange (328/9)+Y with (318/9)+X
CDE2 LDX #&24 ;point to graphics cursor
CDE4 LDY #&14 ;point to last graphics cursor
;A=4 to swap X and Y coordinates
*************** exchange 300/3+Y with 300/3+X ***************************
CDE6 LDA #&04 ;A =4
************** exchange (300/300+A)+Y with (300/300+A)+X *****************
CDE8 STA &DA ;store it as loop counter
CDEA LDA &0300,X ;get byte
\ No newline at end of file
diff --git a/docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/CDED b/docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/CDED
new file mode 100644
index 0000000..ef1ac9b
--- /dev/null
+++ b/docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/CDED
@@ -0,0 +1 @@
+CDED PHA ;store it
CDEE LDA &0300,Y ;get byte pointed to by Y
CDF1 STA &0300,X ;put it in 300+X
CDF4 PLA ;get back A
CDF5 STA &0300,Y ;put it in 300+Y
CDF8 INX ;increment pointers
CDF9 INY ;
CDFA DEC &DA ;decrement loop counter
CDFC BNE &CDEA ;and if not 0 do it again
CDFE RTS ;and exit
******** execute upward scroll ******************************************
;
CDFF JSR &CE5B ;exchange line and column cursors with workspace copies
CE02 LDY &030B ;top of text window
CE05 STY &0319 ;current text line
CE08 JSR &CF06 ;set up display address
CE0B JSR &CAD4 ;add bytes per char. row
CE0E BPL &CE14 ;
CE10 SEC ;
CE11 SBC &0354 ;screen RAM size hi byte
CE14 STA &DB ;(&DA)=X/A
CE16 STX &DA ;
CE18 STA &DC ;&DC=A
CE1A BCC &CE22 ;
CE1C JSR &CE73 ;copy line to new position
;using (&DA) for read
;and (&D8) for write
CE1F JMP &CE2A ;exit
CE22 JSR &CAD4 ;add bytes per char. row
CE25 BMI &CE1C ;if outside screen RAM CE1C
CE27 JSR &CE38 ;perform a copy
CE2A LDA &DC ;
CE2C LDX &DA ;
CE2E STA &D9 ;
CE30 STX &D8 ;
CE32 DEC &DE ;decrement window height
CE34 BNE &CE0B ;CE0B if not 0
CE36 BEQ &CDDA ;exchange text column/linelse CDDA
*********** copy routines ***********************************************
CE38 LDX &034D ;text window width hi (bytes)
CE3B BEQ &CE4D ;if no more than 256 bytes to copy X=0 so CE4D
CE3D LDY #&00 ;Y=0 to set loop counter
CE3F LDA (&DA),Y ;copy 256 bytes
CE41 STA (&D8),Y ;
CE43 INY ;
CE44 BNE &CE3F ;Till Y=0 again
CE46 INC &D9 ;increment hi bytes
CE48 INC &DB ;
CE4A DEX ;decrement window width
CE4B BNE &CE3F ;if not 0 go back and do loop again
CE4D LDY &034C ;text window width lo (bytes)
CE50 BEQ &CE5A ;if Y=0 CE5A
CE52 DEY ;else Y=Y-1
CE53 LDA (&DA),Y ;copy Y bytes
CE55 STA (&D8),Y ;
CE57 TYA ;A=Y
CE58 BNE &CE52 ;if not 0 CE52
CE5A RTS ;and exit
;
CE5B JSR &CDDA ;exchange text column/line with workspace
CE5E SEC ;set carry
CE5F LDA &0309 ;bottom margin
CE62 SBC &030B ;top of text window
CE65 STA &DE ;store it
CE67 BNE &CE6E ;set text column to left hand column
CE69 PLA ;get back return address
CE6A PLA ;
CE6B JMP &CDDA ;exchange text column/line with workspace
CE6E LDA &0308 ;text window left
CE71 BPL &CEE3 ;Jump CEE3 always!
CE73 LDA &DA ;get back A
CE75 PHA ;push A
CE76 SEC ;set carry
CE77 LDA &030A ;text window right
CE7A SBC &0308 ;text window left
CE7D STA &DF ;
CE7F LDY &034F ;bytes per character to set loop counter
CE82 DEY ;copy loop
CE83 LDA (&DA),Y ;
CE85 STA (&D8),Y ;
CE87 DEY ;
CE88 BPL &CE83 ;
CE8A LDX #&02 ;X=2
CE8C CLC ;clear carry
CE8D LDA &D8,X ;
CE8F ADC &034F ;bytes per character
CE92 STA &D8,X ;
CE94 LDA &D9,X ;
CE96 ADC #&00 ;
CE98 BPL &CE9E ;if this remains in screen RAM OK
CE9A SEC ;else wrap around screen
CE9B SBC &0354 ;screen RAM size hi byte
CE9E STA &D9,X ;
CEA0 DEX ;X=X-2
CEA1 DEX ;
CEA2 BEQ &CE8C ;if X=0 adjust second set of pointers
CEA4 DEC &DF ;decrement window width
CEA6 BPL &CE7F ;and if still +ve do it all again
CEA8 PLA ;get back A
CEA9 STA &DA ;and store it
CEAB RTS ;then exit
;
*********** clear a line ************************************************
CEAC LDA &0318 ;text column
CEAF PHA ;save it
CEB0 JSR &CE6E ;set text column to left hand column
CEB3 JSR &CF06 ;set up display address
CEB6 SEC ;set carry
CEB7 LDA &030A ;text window right
CEBA SBC &0308 ;text window left
CEBD STA &DC ;as window width
CEBF LDA &0358 ;background text colour
CEC2 LDY &034F ;bytes per character
CEC5 DEY ;Y=Y-1 decrementing loop counter
CEC6 STA (&D8),Y ;store background colour at this point on screen
CEC8 BNE &CEC5 ;if Y<>0 do it again
CECA TXA ;else A=X
CECB CLC ;clear carry to add
CECC ADC &034F ;bytes per character
CECF TAX ;X=A restoring it
CED0 LDA &D9 ;get hi byte
CED2 ADC #&00 ;Add carry if any
CED4 BPL &CEDA ;if +ve CeDA
CED6 SEC ;else wrap around
CED7 SBC &0354 ;screen RAM size hi byte
CEDA STX &D8 ;restore D8/9
CEDC STA &D9 ;
CEDE DEC &DC ;decrement window width
CEE0 BPL &CEBF ;ind if not 0 do it all again
CEE2 PLA ;get back A
CEE3 STA &0318 ;restore text column
CEE6 SEC ;set carry
CEE7 RTS ;and exit
;
CEE8 LDX &0318 ;text column
CEEB CPX &0308 ;text window left
CEEE BMI &CEE6 ;if less than left margin return with carry set
CEF0 CPX &030A ;text window right
CEF3 BEQ &CEF7 ;if equal to right margin thats OK
CEF5 BPL &CEE6 ;if greater than right margin return with carry set
CEF7 LDX &0319 ;current text line
CEFA CPX &030B ;top of text window
CEFD BMI &CEE6 ;if less than top margin
CEFF CPX &0309 ;bottom margin
CF02 BEQ &CF06 ;set up display address
CF04 BPL &CEE6 ;or greater than bottom margin return with carry set
************:set up display address *************************************
;Mode 0: (0319)*640+(0318)* 8
;Mode 1: (0319)*640+(0318)*16
;Mode 2: (0319)*640+(0318)*32
;Mode 3: (0319)*640+(0318)* 8
;Mode 4: (0319)*320+(0318)* 8
;Mode 5: (0319)*320+(0318)*16
;Mode 6: (0319)*320+(0318)* 8
;Mode 7: (0319)* 40+(0318)
;this gives a displacement relative to the screen RAM start address
;which is added to the calculated number and stored in in 34A/B
;if the result is less than &8000, the top of screen RAM it is copied into X/A
;and D8/9.
;if the result is greater than &7FFF the hi byte of screen RAM size is
;subtracted to wraparound the screen. X/A, D8/9 are then set from this
CF06 LDA &0319 ;current text line
CF09 ASL ;A=A*2
CF0A TAY ;Y=A
CF0B LDA (&E0),Y ;get CRTC multiplication table pointer
CF0D STA &D9 ;&D9=A
CF0F INY ;Y=Y+1
CF10 LDA #&02 ;A=2
CF12 AND &0356 ;memory map type
CF15 PHP ;save flags
CF16 LDA (&E0),Y ;get CRTC multiplication table pointer
CF18 PLP ;pull flags
CF19 BEQ &CF1E ;
CF1B LSR &D9 ;&D9=&D9/2
CF1D ROR ;A=A/2 +(128*carry)
CF1E ADC &0350 ;window area start address lo
CF21 STA &D8 ;store it
CF23 LDA &D9 ;
CF25 ADC &0351 ;window area start address hi
CF28 TAY ;
CF29 LDA &0318 ;text column
CF2C LDX &034F ;bytes per character
CF2F DEX ;X=X-1
CF30 BEQ &CF44 ;if X=0 mode 7 CF44
CF32 CPX #&0F ;is it mode 1 or mode 5?
CF34 BEQ &CF39 ;yes CF39 with carry set
CF36 BCC &CF3A ;if its less (mode 0,3,4,6) CF3A
CF38 ASL ;A=A*16 if entered here (mode 2)
CF39 ASL ;A=A*8 if entered here
CF3A ASL ;A=A*4 if entered here
CF3B ASL ;
CF3C BCC &CF40 ;if carry clear
CF3E INY ;Y=Y+2
CF3F INY ;
CF40 ASL ;A=A*2
CF41 BCC &CF45 ;if carry clear add to &D8
CF43 INY ;if not Y=Y+1
CF44 CLC ;clear carry
CF45 ADC &D8 ;add to &D8
CF47 STA &D8 ;and store it
CF49 STA &034A ;text cursor 6845 address
CF4C TAX ;X=A
CF4D TYA ;A=Y
CF4E ADC #&00 ;Add carry if set
CF50 STA &034B ;text cursor 6845 address
CF53 BPL &CF59 ;if less than &800 goto &CF59
CF55 SEC ;else wrap around
CF56 SBC &0354 ;screen RAM size hi byte
CF59 STA &D9 ;store in high byte
CF5B CLC ;clear carry
CF5C RTS ;and exit
******** Graphics cursor display routine ********************************
CF5D LDX &0359 ;foreground graphics colour
CF60 LDY &035B ;foreground graphics plot mode (GCOL n)
CF63 JSR &D0B3 ;set graphics byte mask in &D4/5
CF66 JSR &D486 ;copy (324/7) graphics cursor to workspace (328/B)
CF69 LDY #&00 ;Y=0
CF6B STY &DC ;&DC=Y
CF6D LDY &DC ;Y=&DC
CF6F LDA (&DE),Y ;get pattern byte
CF71 BEQ &CF86 ;if A=0 CF86
CF73 STA &DD ;else &DD=A
CF75 BPL &CF7A ;and if >0 CF7A
CF77 JSR &D0E3 ;else display a pixel
CF7A INC &0324 ;current horizontal graphics cursor
CF7D BNE &CF82 ;
CF7F INC &0325 ;current horizontal graphics cursor
CF82 ASL &DD ;&DD=&DD*2
CF84 BNE &CF75 ;and if<>0 CF75
CF86 LDX #&28 ;point to workspace
CF88 LDY #&24 ;point to horizontal graphics cursor
CF8A JSR &D482 ;0300/1+Y=0300/1+X
CF8D LDY &0326 ;current vertical graphics cursor
CF90 BNE &CF95 ;
CF92 DEC &0327 ;current vertical graphics cursor
CF95 DEC &0326 ;current vertical graphics cursor
CF98 LDY &DC ;
CF9A INY ;
CF9B CPY #&08 ;if Y<8 then do loop again
CF9D BNE &CF6B ;else
CF9F LDX #&28 ;point to workspace
CFA1 LDY #&24 ;point to graphics cursor
CFA3 JMP &D48A ;(&300/3+Y)=(&300/3+X)
*********** home graphics cursor ***************************************
CFA6 LDX #&06 ;point to graphics window TOP
CFA8 LDY #&26 ;point to workspace
CFAA JSR &D482 ;0300/1+Y=0300/1+X
************* set graphics cursor to left hand column *******************
CFAD LDX #&00 ;X=0 point to graphics window left
CFAF LDY #&24 ;Y=&24
CFB1 JSR &D482 ;0300/1+Y=0300/1+X
CFB4 JMP &D1B8 ;set up external coordinates for graphics
CFB7 LDX &0360 ;number of logical colours less 1
CFBA BEQ &CFDC ;if MODE 7 CFDC
CFBC JSR &D03E ;set up character definition pointers
CFBF LDX &0360 ;number of logical colours less 1
CFC2 LDA &D0 ;VDU status byte
CFC4 AND #&20 ;and out bit 5 printing at graphics cursor
CFC6 BNE &CF5D ;if set CF5D
CFC8 LDY #&07 ;else Y=7
CFCA CPX #&03 ;if X=3
CFCC BEQ &CFEE ;goto CFEE to handle 4 colour modes
CFCE BCS &D01E ;else if X>3 D01E to deal with 16 colours
CFD0 LDA (&DE),Y ;get pattern byte
CFD2 ORA &D2 ;text colour byte to be orred or EORed into memory
CFD4 EOR &D3 ;text colour byte to be orred or EORed into memory
CFD6 STA (&D8),Y ; write to screen
CFD8 DEY ;Y=Y-1
CFD9 BPL &CFD0 ;if still +ve do loop again
CFDB RTS ;and exit
******* convert teletext characters *************************************
;mode 7
CFDC LDY #&02 ;Y=2
CFDE CMP &C4B6,Y ;compare with teletext conversion table
CFE1 BEQ &CFE9 ;if equal then CFE9
CFE3 DEY ;else Y=Y-1
CFE4 BPL &CFDE ;and if +ve CFDE
CFE6 STA (&D8,X) ;if not write byte to screen
CFE8 RTS ;and exit
CFE9 LDA &C4B7,Y ;convert with teletext conversion table
CFEC BNE &CFE6 ;and write it
***********four colour modes ********************************************
CFEE LDA (&DE),Y ;get pattern byte
CFF0 PHA ;save it
CFF1 LSR ;move hi nybble to lo
CFF2 LSR ;
CFF3 LSR ;
CFF4 LSR ;
CFF5 TAX ;X=A
CFF6 LDA &C31F,X ;4 colour mode byte mask look up table
CFF9 ORA &D2 ;text colour byte to be orred or EORed into memory
CFFB EOR &D3 ;text colour byte to be orred or EORed into memory
CFFD STA (&D8),Y ; write to screen
CFFF TYA ;A=Y
D000 CLC ;clear carry
D001 ADC #&08 ;add 8 to move screen RAM pointer 8 bytes
D003 TAY ;Y=A
D004 PLA ;get back A
D005 AND #&0F ;clear high nybble
D007 TAX ;X=A
D008 LDA &C31F,X ;4 colour mode byte mask look up table
D00B ORA &D2 ;text colour byte to be orred or EORed into memory
D00D EOR &D3 ;text colour byte to be orred or EORed into memory
D00F STA (&D8),Y ; write to screen
D011 TYA ;A=Y
D012 SBC #&08 ;A=A-9
D014 TAY ;Y=A
D015 BPL &CFEE ;if +ve do loop again
D017 RTS ;exit
D018 TYA ;Y=Y-&21
D019 SBC #&21 ;
D01B BMI &D017 ;IF Y IS negative then RETURN
D01D TAY ;else A=Y
******* 16 COLOUR MODES *************************************************
D01E LDA (&DE),Y ;get pattern byte
D020 STA &DC ;store it
D022 SEC ;set carry
D023 LDA #&00 ;A=0
D025 ROL &DC ;carry now occupies bit 0 of DC
D027 BEQ &D018 ;when DC=0 again D018 to deal with next pattern byte
D029 ROL ;get bit 7 from &DC into A bit 0
D02A ASL &DC ;rotate again to get second
D02C ROL ;bit into A
D02D TAX ;and store result in X
D02E LDA &C32F,X ;multiply by &55 using look up table
D031 ORA &D2 ;and set colour factors
D033 EOR &D3 ;
D035 STA (&D8),Y ;and store result
D037 CLC ;clear carry
D038 TYA ;Y=Y+8 moving screen RAM pointer on 8 bytes
D039 ADC #&08 ;
D03B TAY ;
D03C BCC &D023 ;iloop to D023 to deal with next bit pair
************* calculate pattern address for given code ******************
;A contains code on entry = 12345678
D03E ASL ;23456780 C holds 1
D03F ROL ;34567801 C holds 2
D040 ROL ;45678012 C holds 3
D041 STA &DE ;save this pattern
D043 AND #&03 ;00000012
D045 ROL ;00000123 C=0
D046 TAX ;X=A=0 - 7
D047 AND #&03 ;A=00000023
D049 ADC #&BF ;A=&BF,C0 or C1
D04B TAY ;this is used as a pointer
D04C LDA &C40D,X ;A=&80/2^X i.e.1,2,4,8,&10,&20,&40, or &80
D04F BIT &0367 ;with font flag
D052 BEQ &D057 ;if 0 D057
D054 LDY &0367,X ;else get hi byte from table
D057 STY &DF ;store Y
D059 LDA &DE ;get back pattern
D05B AND #&F8 ;convert to 45678000
D05D STA &DE ;and re store it
D05F RTS ;exit
;
*************************************************************************
*************************************************************************
** **
** **
** PLOT ROUTINES ENTER HERE **
** **
** **
*************************************************************************
*************************************************************************
;on entry ADDRESS PARAMETER DESCRIPTION
; 031F 1 plot type
; 0320/1 2,3 X coordinate
; 0322/3 4,5 Y coordinate
D060 LDX #&20 ;X=&20
D062 JSR &D14D ;translate coordinates
D065 LDA &031F ;get plot type
D068 CMP #&04 ;if its 4
D06A BEQ &D0D9 ;D0D9 move absolute
D06C LDY #&05 ;Y=5
D06E AND #&03 ;mask only bits 0 and 1
D070 BEQ &D080 ;if result is 0 then its a move (multiple of 8)
D072 LSR ;else move bit 0 int C
D073 BCS &D078 ;if set then D078 graphics colour required
D075 DEY ;Y=4
D076 BNE &D080 ;logic inverse colour must be wanted
******** graphics colour wanted *****************************************
D078 TAX ;X=A if A=0 its a foreground colour 1 its background
D079 LDY &035B,X ;get fore or background graphics PLOT mode
D07C LDA &0359,X ;get fore or background graphics colour
D07F TAX ;X=A
D080 JSR &D0B3 ;set up colour masks in D4/5
D083 LDA &031F ;get plot type
D086 BMI &D0AB ;if &80-&FF then D0AB type not implemented
D088 ASL ;bit 7=bit 6
D089 BPL &D0C6 ;if bit 6 is 0 then plot type is 0-63 so D0C6
D08B AND #&F0 ;else mask out lower nybble
D08D ASL ;shift old bit 6 into C bit old 5 into bit 7
D08E BEQ &D0D6 ;if 0 then type 64-71 was called single point plot
;goto D0D6
D090 EOR #&40 ;if bit 6 NOT set type &80-&87 fill triangle
D092 BEQ &D0A8 ;so D0A8
D094 PHA ;else push A
D095 JSR &D0DC ;copy 0320/3 to 0324/7 setting XY in current graphics
;coordinates
D098 PLA ;get back A
D099 EOR #&60 ;if BITS 6 and 5 NOT SET type 72-79 lateral fill
D09B BEQ &D0AE ;so D0AE
D09D CMP #&40 ;if type 88-95 horizontal line blanking
D09F BNE &D0AB ;so D0AB
D0A1 LDA #&02 ;else A=2
D0A3 STA &DC ;store it
D0A5 JMP &D506 ;and jump to D506 type not implemented
D0A8 JMP &D5EA ;to fill triangle routine
D0AB JMP &C938 ;VDU extension access entry
D0AE STA &DC ;store A
D0B0 JMP &D4BF ;
*********:set colour masks **********************************************
;graphics mode in Y
;colour in X
D0B3 TXA ;A=X
D0B4 ORA &C41C,Y ;or with GCOL plot options table byte
D0B7 EOR &C41D,Y ;EOR with following byte
D0BA STA &D4 ;and store it
D0BC TXA ;A=X
D0BD ORA &C41B,Y ;
D0C0 EOR &C420,Y ;
D0C3 STA &D5 ;
D0C5 RTS ;exit with masks in &D4/5
************** analyse first parameter in 0-63 range ********************
;
D0C6 ASL ;shift left again
D0C7 BMI &D0AB ;if -ve options are in range 32-63 not implemented
D0C9 ASL ;shift left twice more
D0CA ASL ;
D0CB BPL &D0D0 ;if still +ve type is 0-7 or 16-23 so D0D0
D0CD JSR &D0EB ;else display a point
D0D0 JSR &D1ED ;perform calculations
D0D3 JMP &D0D9 ;
*************************************************************************
* *
* PLOT A SINGLE POINT *
* *
*************************************************************************
D0D6 JSR &D0EB ;display a point
D0D9 JSR &CDE2 ;swap current and last graphics position
D0DC LDY #&24 ;Y=&24
D0DE LDX #&20 ;X=&20
D0E0 JMP &D48A ;copy parameters to 324/7 (300/3 +Y)
D0E3 LDX #&24 ;
D0E5 JSR &D85F ;calculate position
D0E8 BEQ &D0F0 ;if result =0 then D0F0
D0EA RTS ;else exit
;
D0EB JSR &D85D ;calculate position
D0EE BNE &D103 ;if A<>0 D103 and return
D0F0 LDY &031A ;else get current graphics scan line
D0F3 LDA &D1 ;pick up and modify screen byte
D0F5 AND &D4 ;
D0F7 ORA (&D6),Y ;
D0F9 STA &DA ;
D0FB LDA &D5 ;
D0FD AND &D1 ;
D0FF EOR &DA ;
D101 STA (&D6),Y ;put it back again
D103 RTS ;and exit
;
D104 LDA (&D6),Y ;this is a more simplistic version of the above
D106 ORA &D4 ;
D108 EOR &D5 ;
D10A STA (&D6),Y ;
D10C RTS ;and exit
\ No newline at end of file
diff --git a/docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/D10D b/docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/D10D
new file mode 100644
index 0000000..7978697
--- /dev/null
+++ b/docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/D10D
@@ -0,0 +1 @@
+************************** Check window limits *************************
;
D10D LDX #&24 ;X=&24
D10F LDY #&00 ;Y=0
D111 STY &DA ;&DA=0
D113 LDY #&02 ;Y=2
D115 JSR &D128 ;check vertical graphics position 326/7
;bottom and top margins 302/3, 306/7
D118 ASL &DA ;DATA is set in &DA bits 0 and 1 then shift left
D11A ASL &DA ;twice to make room for next pass
D11C DEX ;X=&22
D11D DEX ;
D11E LDY #&00 ;Y=0
D120 JSR &D128 ;left and right margins 300/1, 304/5
;cursor horizontal position 324/5
D123 INX ;X=X+2
D124 INX ;
D125 LDA &DA ;A=&DA
D127 RTS ;exit
*** cursor and margins check ******************************************
;
D128 LDA &0302,X ;check for window violation
D12B CMP &0300,Y ;300/1 +Y > 302/3+X
D12E LDA &0303,X ;then window fault
D131 SBC &0301,Y ;
D134 BMI &D146 ;so D146
D136 LDA &0304,Y ;check other windows
D139 CMP &0302,X ;
D13C LDA &0305,Y ;
D13F SBC &0303,X ;
D142 BPL &D148 ;if no violation exit
D144 INC &DA ;else DA=DA+1
D146 INC &DA ;DA=DA+1
D148 RTS ;and exit DA=0 no problems DA=1 first check 2, 2nd
;
***********set up and adjust positional data ****************************
D149 LDA #&FF ;A=&FF
D14B BNE &D150 ;then &D150
D14D LDA &031F ;get first parameter in plot
D150 STA &DA ;store in &DA
D152 LDY #&02 ;Y=2
D154 JSR &D176 ;set up vertical coordinates/2
D157 JSR &D1AD ;/2 again to convert 1023 to 0-255 for internal use
;this is why minimum vertical plot separation is 4
D15A LDY #&00 ;Y=0
D15C DEX ;X=x-2
D15D DEX ;
D15E JSR &D176 ;set up horiz. coordinates/2 this is OK for mode0,4
D161 LDY &0361 ;get number of pixels/byte (-1)
D164 CPY #&03 ;if Y=3 (modes 1 and 5)
D166 BEQ &D16D ;D16D
D168 BCS &D170 ;for modes 0 & 4 this is 7 so D170
D16A JSR &D1AD ;for other modes divide by 2 twice
D16D JSR &D1AD ;divide by 2
D170 LDA &0356 ;get screen display type
D173 BNE &D1AD ;if not 0 (modes 3-7) divide by 2 again
D175 RTS ;and exit
;for mode 0 1 division 1280 becomes 640 = horizontal resolution
;for mode 1 2 divisions 1280 becomes 320 = horizontal resolution
;for mode 2 3 divisions 1280 becomes 160 = horizontal resolution
;for mode 4 2 divisions 1280 becomes 320 = horizontal resolution
;for mode 5 3 divisions 1280 becomes 160 = horizontal resolution
********** calculate external coordinates in internal format ***********
;on entry X is usually &1E or &20
;
D176 CLC ;clear carry
D177 LDA &DA ;get &DA
D179 AND #&04 ;if bit 2=0
D17B BEQ &D186 ;then D186 to calculate relative coordinates
D17D LDA &0302,X ;else get coordinate
D180 PHA ;
D181 LDA &0303,X ;
D184 BCC &D194 ;and goto D194
D186 LDA &0302,X ;get coordinate
D189 ADC &0310,Y ;add cursor position
D18C PHA ;save it
D18D LDA &0303,X ;
D190 ADC &0311,Y ;add cursor
D193 CLC ;clear carry
D194 STA &0311,Y ;save new cursor
D197 ADC &030D,Y ;add graphics origin
D19A STA &0303,X ;store it
D19D PLA ;get back lo byte
D19E STA &0310,Y ;save it in new cursor lo
D1A1 CLC ;clear carry
D1A2 ADC &030C,Y ;add to graphics orgin
D1A5 STA &0302,X ;store it
D1A8 BCC &D1AD ;if carry set
D1AA INC &0303,X ;increment hi byte as you would expect!
D1AD LDA &0303,X ;get hi byte
D1B0 ASL ;
D1B1 ROR &0303,X ;divide by 2
D1B4 ROR &0302,X ;
D1B7 RTS ;and exit
;
***** calculate external coordinates from internal coordinates************
D1B8 LDY #&10 ;Y=10
D1BA JSR &D488 ;copy 324/7 to 310/3 i.e.current graphics cursor
;position to position in external values
D1BD LDX #&02 ;X=2
D1BF LDY #&02 ;Y=2
D1C1 JSR &D1D5 ;multiply 312/3 by 4 and subtract graphics origin
D1C4 LDX #&00 ;X=0
D1C6 LDY #&04 ;Y=4
D1C8 LDA &0361 ;get number of pixels/byte
D1CB DEY ;Y=Y-1
D1CC LSR ;divide by 2
D1CD BNE &D1CB ;if result not 0 D1CB
D1CF LDA &0356 ;else get screen display type
D1D2 BEQ &D1D5 ;and if 0 D1D5
D1D4 INY ;
D1D5 ASL &0310,X ;multiply coordinate by 2
D1D8 ROL &0311,X ;
D1DB DEY ;Y-Y-1
D1DC BNE &D1D5 ;and if Y<>0 do it again
D1DE SEC ;set carry
D1DF JSR &D1E3 ;
D1E2 INX ;increment X
D1E3 LDA &0310,X ;get current graphics position in external coordinates
D1E6 SBC &030C,X ;subtract origin
D1E9 STA &0310,X ;store in graphics position
D1EC RTS ;and exit
;
************* compare X and Y PLOT spans ********************************
D1ED JSR &D40D ;Set X and Y spans in workspace 328/9 32A/B
D1F0 LDA &032B ;compare spans
D1F3 EOR &0329 ;if result -ve spans are different in sign so
D1F6 BMI &D207 ;goto D207
D1F8 LDA &032A ;else A=hi byte of difference in spans
D1FB CMP &0328 ;
D1FE LDA &032B ;
D201 SBC &0329 ;
D204 JMP &D214 ;and goto D214
D207 LDA &0328 ;A = hi byte of SUM of spans
D20A CLC ;
D20B ADC &032A ;
D20E LDA &0329 ;
D211 ADC &032B ;
D214 ROR ;A=A/2
D215 LDX #&00 ;X=0
D217 EOR &032B ;
D21A BPL &D21E ;if positive result D21E
D21C LDX #&02 ;else X=2
D21E STX &DE ;store it
D220 LDA &C4AA,X ;set up vector address
D223 STA &035D ;in 35D
D226 LDA &C4AB,X ;
D229 STA &035E ;and 35E
D22C LDA &0329,X ;get hi byte of span
D22F BPL &D235 ;if +ve D235
D231 LDX #&24 ;X=&24
D233 BNE &D237 ;jump to D237
D235 LDX #&20 ;X=&20
D237 STX &DF ;store it
D239 LDY #&2C ;Y=&2C
D23B JSR &D48A ;get X coordinate data or horizontal coord of
;curent graphics cursor
D23E LDA &DF ;get back original X
D240 EOR #&04 ;covert &20 to &24 and vice versa
D242 STA &DD ;
D244 ORA &DE ;
D246 TAX ;
D247 JSR &D480 ;copy 330/1 to 300/1+X
D24A LDA &031F ;get plot type
D24D AND #&10 ;check bit 4
D24F ASL ;
D250 ASL ;
D251 ASL ;move to bit 7
D252 STA &DB ;store it
D254 LDX #&2C ;X=&2C
D256 JSR &D10F ;check for window violations
D259 STA &DC ;
D25B BEQ &D263 ;if none then D263
D25D LDA #&40 ;else set bit 6 of &DB
D25F ORA &DB ;
D261 STA &DB ;
D263 LDX &DD ;
D265 JSR &D10F ;check window violations again
D268 BIT &DC ;if bit 7 of &DC NOT set
D26A BEQ &D26D ;D26D
D26C RTS ;else exit
;
D26D LDX &DE ;X=&DE
D26F BEQ &D273 ;if X=0 D273
D271 LSR ;A=A/2
D272 LSR ;A=A/2
D273 AND #&02 ;clear all but bit 2
D275 BEQ &D27E ;if bit 2 set D27E
D277 TXA ;else A=X
D278 ORA #&04 ;A=A or 4 setting bit 3
D27A TAX ;X=A
D27B JSR &D480 ;set 300/1+x to 330/1
D27E JSR &D42C ;more calcualtions
D281 LDA &DE ;A=&DE EOR 2
D283 EOR #&02 ;
D285 TAX ;X=A
D286 TAY ;Y=A
D287 LDA &0329 ;compare upper byte of spans
D28A EOR &032B ;
D28D BPL &D290 ;if signs are the same D290
D28F INX ;else X=X+1
D290 LDA &C4AE,X ;get vector addresses and store 332/3
D293 STA &0332 ;
D296 LDA &C4B2,X ;
D299 STA &0333 ;
D29C LDA #&7F ;A=&7F
D29E STA &0334 ;store it
D2A1 BIT &DB ;if bit 6 set
D2A3 BVS &D2CE ;the D2CE
D2A5 LDA &C447,X ;get VDU section number
D2A8 TAX ;X=A
D2A9 SEC ;set carry
D2AA LDA &0300,X ;subtract coordinates
D2AD SBC &032C,Y ;
D2B0 STA &DA ;
D2B2 LDA &0301,X ;
D2B5 SBC &032D,Y ;
D2B8 LDY &DA ;Y=hi
D2BA TAX ;X=lo=A
D2BB BPL &D2C0 ;and if A+Ve D2C0
D2BD JSR &D49B ;negate Y/A
D2C0 TAX ;X=A increment Y/A
D2C1 INY ;Y=Y+1
D2C2 BNE &D2C5 ;
D2C4 INX ;X=X+1
D2C5 TXA ;A=X
D2C6 BEQ &D2CA ;if A=0 D2CA
D2C8 LDY #&00 ;else Y=0
D2CA STY &DF ;&DF=Y
D2CC BEQ &D2D7 ;if 0 then D2D7
D2CE TXA ;A=X
D2CF LSR ;A=A/4
D2D0 ROR ;
D2D1 ORA #&02 ;bit 1 set
D2D3 EOR &DE ;
D2D5 STA &DE ;and store
D2D7 LDX #&2C ;X=&2C
D2D9 JSR &D864 ;
D2DC LDX &DC ;
D2DE BNE &D2E2 ;
D2E0 DEC &DD ;
D2E2 DEX ;X=X-1
D2E3 LDA &DB ;A=&3B
D2E5 BEQ &D306 ;if 0 D306
D2E7 BPL &D2F9 ;else if +ve D2F9
D2E9 BIT &0334 ;
D2EC BPL &D2F3 ;if bit 7=0 D2F3
D2EE DEC &0334 ;else decrement
D2F1 BNE &D316 ;and if not 0 D316
D2F3 INC &0334 ;
D2F6 ASL ;A=A*2
D2F7 BPL &D306 ;if +ve D306
D2F9 STX &DC ;
D2FB LDX #&2C ;
D2FD JSR &D85F ;calcualte screen position
D300 LDX &DC ;get back original X
D302 ORA #&00 ;
D304 BNE &D316 ;
D306 LDA &D1 ;byte mask for current graphics point
D308 AND &D4 ;and with graphics colour byte
D30A ORA (&D6),Y ;or with curent graphics cell line
D30C STA &DA ;store result
D30E LDA &D5 ;same again with next byte (hi??)
D310 AND &D1 ;
D312 EOR &DA ;
D314 STA (&D6),Y ;then store it inm current graphics line
D316 SEC ;set carry
D317 LDA &0335 ;A=&335/6-&337/8
D31A SBC &0337 ;
D31D STA &0335 ;
D320 LDA &0336 ;
D323 SBC &0338 ;
D326 BCS &D339 ;if carry set D339
D328 STA &DA ;
D32A LDA &0335 ;
D32D ADC &0339 ;
D330 STA &0335 ;
D333 LDA &DA ;
D335 ADC &033A ;
D338 CLC ;
D339 STA &0336 ;
D33C PHP ;
D33D BCS &D348 ;if carry clear jump to VDU routine else D348
D33F JMP (&0332) ;
****** vertical scan module 1******************************************
D342 DEY ;Y=Y-1
D343 BPL &D348 ;if + D348
D345 JSR &D3D3 ;else d3d3 to advance pointers
D348 JMP (&035D) ;and JUMP (&35D)
****** vertical scan module 2******************************************
D34B INY ;Y=Y+1
D34C CPY #&08 ;if Y<>8
D34E BNE &D348 ;then D348
D350 CLC ;else clear carry
D351 LDA &D6 ;get address of top line of cuirrent graphics cell
D353 ADC &0352 ;add number of bytes/character row
D356 STA &D6 ;store it
D358 LDA &D7 ;do same for hibyte
D35A ADC &0353 ;
D35D BPL &D363 ;if result -ve then we are above screen RAM
D35F SEC ;so
D360 SBC &0354 ;subtract screen memory size hi
D363 STA &D7 ;store it this wraps around point to screen RAM
D365 LDY #&00 ;Y=0
D367 JMP (&035D) ;
****** horizontal scan module 1******************************************
D36A LSR &D1 ;shift byte mask
D36C BCC &D348 ;if carry clear (&D1 was +ve) goto D348
D36E JSR &D3ED ;else reset pointers
D371 JMP (&035D) ;and off to do more
****** horizontal scan module 2******************************************
D374 ASL &D1 ;shift byte mask
D376 BCC &D348 ;if carry clear (&D1 was +ve) goto D348
D378 JSR &D3FD ;else reset pointers
D37B JMP (&035D) ;and off to do more
D37E DEY ;Y=Y-1
D37F BPL &D38D ;if +ve D38D
D381 JSR &D3D3 ;advance pointers
D384 BNE &D38D ;goto D38D normally
D386 LSR &D1 ;shift byte mask
D388 BCC &D38D ;if carry clear (&D1 was +ve) goto D348
D38A JSR &D3ED ;else reset pointers
D38D PLP ;pull flags
D38E INX ;X=X+1
D38F BNE &D395 ;if X>0 D395
D391 INC &DD ;else increment &DD
D393 BEQ &D39F ;and if not 0 D39F
D395 BIT &DB ;else if BIT 6 = 1
D397 BVS &D3A0 ;goto D3A0
D399 BCS &D3D0 ;if BIT 7=1 D3D0
D39B DEC &DF ;else Decrement &DF
D39D BNE &D3D0 ;and if not Zero D3D0
D39F RTS ;else return
;
D3A0 LDA &DE ;A=&DE
D3A2 STX &DC ;&DC=X
D3A4 AND #&02 ;clear all but bit 1
D3A6 TAX ;X=A
D3A7 BCS &D3C2 ;and if carry set goto D3C2
D3A9 BIT &DE ;if Bit 7 of &DE =1
D3AB BMI &D3B7 ;then D3B7
D3AD INC &032C,X ;else increment
D3B0 BNE &D3C2 ;and if not 0 D3C2
D3B2 INC &032D,X ;else increment hi byte
D3B5 BCC &D3C2 ;and if carry clear D3C2
D3B7 LDA &032C,X ;esle A=32C,X
D3BA BNE &D3BF ;and if not 0 D3BF
D3BC DEC &032D,X ;decrement hi byte
D3BF DEC &032C,X ;decrement lo byte
D3C2 TXA ;A=X
D3C3 EOR #&02 ;invert bit 2
D3C5 TAX ;X=A
D3C6 INC &032C,X ;Increment 32C/D
D3C9 BNE &D3CE ;
D3CB INC &032D,X ;
D3CE LDX &DC ;X=&DC
D3D0 JMP &D2E3 ;jump to D2E3
**********move display point up a line **********************************
D3D3 SEC ;SET CARRY
D3D4 LDA &D6 ;subtract number of bytes/line from address of
D3D6 SBC &0352 ;top line of current graphics cell
D3D9 STA &D6 ;
D3DB LDA &D7 ;
D3DD SBC &0353 ;
D3E0 CMP &034E ;compare with bottom of screen memory
D3E3 BCS &D3E8 ;if outside screen RAM
D3E5 ADC &0354 ;add screen memory size to wrap it around
D3E8 STA &D7 ;store in current address of graphics cell top line
D3EA LDY #&07 ;Y=7
D3EC RTS ;and RETURN
;
D3ED LDA &0362 ;get current left colour mask
D3F0 STA &D1 ;store it
D3F2 LDA &D6 ;get current top line of graphics cell
D3F4 ADC #&07 ;ADD 7
D3F6 STA &D6 ;
D3F8 BCC &D3FC ;
D3FA INC &D7 ;
D3FC RTS ;and return
;
D3FD LDA &0363 ;get right colour mask
D400 STA &D1 ;store it
D402 LDA &D6 ;A=top line graphics cell low
D404 BNE &D408 ;if not 0 D408
D406 DEC &D7 ;else decrement hi byte
D408 SBC #&08 ;subtract 9 (8 + carry)
D40A STA &D6 ;and store in low byte
D40C RTS ;return
;
********:: coordinate subtraction ***************************************
D40D LDY #&28 ;X=&28
D40F LDX #&20 ;Y=&20
D411 JSR &D418 ;
D414 INX ;X=X+2
D415 INX ;
D416 INY ;Y=Y+2
D417 INY ;
D418 SEC ;set carry
D419 LDA &0304,X ;subtract coordinates
D41C SBC &0300,X ;
D41F STA &0300,Y ;
D422 LDA &0305,X ;
D425 SBC &0301,X ;
D428 STA &0301,Y ;
D42B RTS ;and return
;
D42C LDA &DE ;A=&DE
D42E BNE &D437 ;if A=0 D437
D430 LDX #&28 ;X=&28
D432 LDY #&2A ;Y=&2A
D434 JSR &CDDE ;exchange 300/1+Y with 300/1+X
;IN THIS CASE THE X AND Y SPANS!
D437 LDX #&28 ;X=&28
D439 LDY #&37 ;Y=&37
D43B JSR &D48A ;copy &300/4+Y to &300/4+X
;transferring X and Y spans in this case
D43E SEC ;set carry
D43F LDX &DE ;X=&DE
D441 LDA &0330 ;subtract 32C/D,X from 330/1
D444 SBC &032C,X ;
D447 TAY ;partial answer in Y
D448 LDA &0331 ;
D44B SBC &032D,X ;
D44E BMI &D453 ;if -ve D453
D450 JSR &D49B ;else negate Y/A
D453 STA &DD ;store A
D455 STY &DC ;and Y
D457 LDX #&35 ;X=&35
D459 JSR &D467 ;get coordinates
D45C LSR ;
D45D STA &0301,X ;
D460 TYA ;
D461 ROR ;
D462 STA &0300,X ;
D465 DEX ;
D466 DEX ;
D467 LDY &0304,X ;
D46A LDA &0305,X ;
D46D BPL &D47B ;if A is +ve RETURN
D46F JSR &D49B ;else negate Y/A
D472 STA &0305,X ;store back again
D475 PHA ;
D476 TYA ;
D477 STA &0304,X ;
D47A PLA ;get back A
D47B RTS ;and exit
;
D47C LDA #&08 ;A=8
D47E BNE &D48C ;copy 8 bytes
D480 LDY #&30 ;Y=&30
D482 LDA #&02 ;A=2
D484 BNE &D48C ;copy 2 bytes
D486 LDY #&28 ;copy 4 bytes from 324/7 to 328/B
D488 LDX #&24 ;
D48A LDA #&04 ;
***********copy A bytes from 300,X to 300,Y ***************************
D48C STA &DA ;
D48E LDA &0300,X ;
D491 STA &0300,Y ;
D494 INX ;
D495 INY ;
D496 DEC &DA ;
D498 BNE &D48E ;
D49A RTS ;and return
;
************* negation routine ******************************************
D49B PHA ;save A
D49C TYA ;A=Y
D49D EOR #&FF ;invert
D49F TAY ;Y=A
D4A0 PLA ;get back A
D4A1 EOR #&FF ;invert
D4A3 INY ;Y=Y+1
D4A4 BNE &D4A9 ;if not 0 exit
D4A6 CLC ;else
D4A7 ADC #&01 ;add 1 to A
D4A9 RTS ;return
;
D4AA JSR &D85D ;check window boundaries and set up screen pointer
D4AD BNE &D4B7 ;if A<>0 D4B7
D4AF LDA (&D6),Y ;else get byte from current graphics cell
D4B1 EOR &035A ;compare with current background colour
D4B4 STA &DA ;store it
D4B6 RTS ;and RETURN
;
D4B7 PLA ;get back return link
D4B8 PLA ;
D4B9 INC &0326 ;increment current graphics cursor vertical lo
D4BC JMP &D545 ;
\ No newline at end of file
diff --git a/docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/D4BF b/docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/D4BF
new file mode 100644
index 0000000..2d10030
--- /dev/null
+++ b/docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/D4BF
@@ -0,0 +1 @@
+OS SERIES IV
GEOFF COX
*************************************************************************
* *
* LATERAL FILL ROUTINE *
* *
*************************************************************************
D4BF JSR &D4AA ;check current screen state
D4C2 AND &D1 ;if A and &D1 <> 0 a plotted point has been found
D4C4 BNE &D4B9 ;so D4B9
D4C6 LDX #&00 ;X=0
D4C8 JSR &D592 ;update pointers
D4CB BEQ &D4FA ;if 0 then D4FA
D4CD LDY &031A ;else Y=graphics scan line
D4D0 ASL &D1 ;
D4D2 BCS &D4D9 ;if carry set D4D9
D4D4 JSR &D574 ;else D574
D4D7 BCC &D4FA ;if carry clear D4FA
D4D9 JSR &D3FD ;else D3FD to pick up colour multiplier
D4DC LDA (&D6),Y ;get graphics cell line
D4DE EOR &035A ;EOR with background colour
D4E1 STA &DA ;and store
D4E3 BNE &D4F7 ;if not 0 D4F7
D4E5 SEC ;else set carry
D4E6 TXA ;A=X
D4E7 ADC &0361 ;add pixels/byte
D4EA BCC &D4F0 ;and if carry clear D4F0
D4EC INC &DB ;else increment &DB
D4EE BPL &D4F7 ;and if +ve D4F7
D4F0 TAX ;else X=A
D4F1 JSR &D104 ;display a pixel
D4F4 SEC ;set carry
D4F5 BCS &D4D9 ;goto D4D9
D4F7 JSR &D574 ;
D4FA LDY #&00 ;Y=0
D4FC JSR &D5AC ;
D4FF LDY #&20 ;
D501 LDX #&24 ;
D503 JSR &CDE6 ;exchange 300/3 +Y with 300/3+X
D506 JSR &D4AA ;check screen pixel
D509 LDX #&04 ;Y=5
D50B JSR &D592 ;
D50E TXA ;A=x
D50F BNE &D513 ;if A<>0 d513
D511 DEC &DB ;else &DB=&dB-1
D513 DEX ;X=X-1
D514 JSR &D54B ;
D517 BCC &D540 ;
D519 JSR &D3ED ;update pointers
D51C LDA (&D6),Y ;get byte from graphics line
D51E EOR &035A ;EOR with background colour
D521 STA &DA ;and store it
D523 LDA &DC ;
D525 BNE &D514 ;If A-0 back to D514
D527 LDA &DA ;else A=&DA
D529 BNE &D53D ;if A<>d53D
D52B SEC ;else set carry
D52C TXA ;A=x
D52D ADC &0361 ;Add number of pixels/byte
D530 BCC &D536 ;and if carry clear D536
D532 INC &DB ;else inc DB
D534 BPL &D53D ;and if +ve D53D
D536 TAX ;get back X
D537 JSR &D104 ;display a point
D53A SEC ;set carry
D53B BCS &D519 ;goto D519
D53D JSR &D54B ;
D540 LDY #&04 ;
D542 JSR &D5AC ;
D545 JSR &D0D9 ;
D548 JMP &D1B8 ;scale pointers
D54B LDA &D1 ;get byte mask
D54D PHA ;save it
D54E CLC ;clear carry
D54F BCC &D560 ;
D551 PLA ;get back A
D552 INX ;X=X+1
D553 BNE &D559 ;if not 0 D559
D555 INC &DB ;else inc &DB
D557 BPL &D56F ;if +ve D56F
D559 LSR &D1 ;
D55B BCS &D56F ;if Bit 7 D1 set D56F
D55D ORA &D1 ;else or withA
D55F PHA ;save result
D560 LDA &D1 ;A=&D1
D562 BIT &DA ;test bits 6 and 7 of &DA
D564 PHP ;save flags
D565 PLA ;get into A
D566 EOR &DC ;EOR and DC
D568 PHA ;save A
D569 PLP ;
D56A BEQ &D551 ;
D56C PLA ;A=A EOR &D1 (byte mask)
D56D EOR &D1 ;
D56F STA &D1 ;store it
D571 JMP &D0F0 ;and display a pixel
D574 LDA #&00 ;A=0
D576 CLC ;Clear carry
D577 BCC &D583 ;goto D583 if carry clear
D579 INX ;X=X+1
D57A BNE &D580 ;If <>0 D580
D57C INC &DB ;else inc &DB
D57E BPL &D56F ;and if +ve d56F
D580 ASL ;A=A*2
D581 BCS &D58E ;if C set D58E
D583 ORA &D1 ;else A=A OR (&D1)
D585 BIT &DA ;set V and M from &DA b6 b7
D587 BEQ &D579 ;
D589 EOR &D1 ;A=AEOR &D1
D58B LSR ;/2
D58C BCC &D56F ;if carry clear D56F
D58E ROR ;*2
D58F SEC ;set carry
D590 BCS &D56F ;to D56F
D592 LDA &0300,X ;Y/A=(&300/1 +X)-(&320/1)
D595 SEC ;
D596 SBC &0320 ;
D599 TAY ;
D59A LDA &0301,X ;
D59D SBC &0321 ;
D5A0 BMI &D5A5 ;if result -ve D5A5
D5A2 JSR &D49B ;or negate Y/A
D5A5 STA &DB ;store A
D5A7 TYA ;A=Y
D5A8 TAX ;X=A
D5A9 ORA &DB ;
D5AB RTS ;exit
;
D5AC STY &DA ;Y=&DA
D5AE TXA ;A=X
D5AF TAY ;Y=A
D5B0 LDA &DB ;A=&DB
D5B2 BMI &D5B6 ;if -ve D5B6
D5B4 LDA #&00 ;A=0
D5B6 LDX &DA ;X=&DA
D5B8 BNE &D5BD ;if <>0 D5BD
D5BA JSR &D49B ;negate
D5BD PHA ;
D5BE CLC ;
D5BF TYA ;
D5C0 ADC &0300,X ;Y/A+(&300/1 +X)=(&320/1)
D5C3 STA &0320 ;
D5C6 PLA ;
D5C7 ADC &0301,X ;
D5CA STA &0321 ;
D5CD RTS ;return
*************************************************************************
* *
* OSWORD 13 - READ LAST TWO GRAPHIC CURSOR POSITIONS *
* *
*************************************************************************
;
D5CE LDA #&03 ;A=3
D5D0 JSR &D5D5 ;
D5D3 LDA #&07 ;A=7
D5D5 PHA ;Save A
D5D6 JSR &CDE2 ;exchange last 2 graphics cursor coordinates with
;current coordinates
D5D9 JSR &D1B8 ;convert to external coordinates
D5DC LDX #&03 ;X=3
D5DE PLA ;save A
D5DF TAY ;Y=A
D5E0 LDA &0310,X ;get graphics coordinate
D5E3 STA (&F0),Y ;store it in OS buffer
D5E5 DEY ;decrement Y and X
D5E6 DEX ;
D5E7 BPL &D5E0 ;if +ve do it again
D5E9 RTS ;then Exit
;
*************************************************************************
* *
* PLOT Fill triangle routine *
* *
*************************************************************************
D5EA LDX #&20 ;X=&20
D5EC LDY #&3E ;Y=&3E
D5EE JSR &D47C ;copy 300/7+X to 300/7+Y
;this gets XY data parameters and current graphics
;cursor position
D5F1 JSR &D632 ;exchange 320/3 with 324/7 if 316/7=<322/3
D5F4 LDX #&14 ;X=&14
D5F6 LDY #&24 ;Y=&24
D5F8 JSR &D636 ;
D5FB JSR &D632 ;
D5FE LDX #&20 ;
D600 LDY #&2A ;
D602 JSR &D411 ;calculate 032A/B-(324/5-320/1)
D605 LDA &032B ;and store
D608 STA &0332 ;result
D60B LDX #&28 ;set pointers
D60D JSR &D459 ;
D610 LDY #&2E ;
D612 JSR &D0DE ;copy 320/3 32/31
D615 JSR &CDE2 ;exchange 314/7 with 324/7
D618 CLC ;
D619 JSR &D658 ;execute fill routine
D61C JSR &CDE2 ;
D61F LDX #&20 ;
D621 JSR &CDE4 ;
D624 SEC ;
D625 JSR &D658 ;
D628 LDX #&3E ;;X=&3E
D62A LDY #&20 ;;Y=&20
D62C JSR &D47C ;;copy 300/7+X to 300/7+Y
D62F JMP &D0D9 ;;this gets XY data parameters and current graphics
;cursor position
D632 LDX #&20 ;X=&20
D634 LDY #&14 ;Y=&14
D636 LDA &0302,X ;
D639 CMP &0302,Y ;
D63C LDA &0303,X ;
D63F SBC &0303,Y ;
D642 BMI &D657 ;if 302/3+Y>302/3+X return
D644 JMP &CDE6 ;else swap 302/3+X with 302/3+Y
;
*************************************************************************
* *
* OSBYTE 134 - READ CURSOR POSITION *
* *
*************************************************************************
D647 LDA &0318 ;read current text cursor (X)
D64A SEC ;set carry
D64B SBC &0308 ;subtract left hand column of current text window
D64E TAX ;X=A
D64F LDA &0319 ;get current text cursor (Y)
D652 SEC ;
D653 SBC &030B ;suptract top row of current window
D656 TAY ;Y=A
D657 RTS ;and exit
;PLOT routines continue
;many of the following routines are just manipulations
;only points of interest will be explained
D658 PHP ;store flags
D659 LDX #&20 ;X=&20
D65B LDY #&35 ;Y=&35
D65D JSR &D411 ;335/6=(324/5+X-320/1)
D660 LDA &0336 ;
D663 STA &033D ;
D666 LDX #&33 ;
D668 JSR &D459 ;set pointers
D66B LDY #&39 ;set 339/C=320/3
D66D JSR &D0DE ;
D670 SEC ;
D671 LDA &0322 ;
D674 SBC &0326 ;
D677 STA &031B ;
D67A LDA &0323 ;
D67D SBC &0327 ;
D680 STA &031C ;
D683 ORA &031B ;check VDU queque
D686 BEQ &D69F ;
D688 JSR &D6A2 ;display a line
D68B LDX #&33 ;
D68D JSR &D774 ;update pointers
D690 LDX #&28 ;
D692 JSR &D774 ;and again!
D695 INC &031B ;update VDU queque
D698 BNE &D688 ;and if not empty do it again
D69A INC &031C ;else increment next byte
D69D BNE &D688 ;and do it again
D69F PLP ;pull flags
D6A0 BCC &D657 ;if carry clear exit
D6A2 LDX #&39 ;
D6A4 LDY #&2E ;
D6A6 STX &DE ;
D6A8 LDA &0300,X ;is 300/1+x<300/1+Y
D6AB CMP &0300,Y ;
D6AE LDA &0301,X ;
D6B1 SBC &0301,Y ;
D6B4 BMI &D6BC ;if so D6BC
D6B6 TYA ;else A=Y
D6B7 LDY &DE ;Y=&DE
D6B9 TAX ;X=A
D6BA STX &DE ;&DE=X
D6BC STY &DF ;&DF=Y
D6BE LDA &0300,Y ;
D6C1 PHA ;
D6C2 LDA &0301,Y ;
D6C5 PHA ;
D6C6 LDX &DF ;
D6C8 JSR &D10F ;check for window violations
D6CB BEQ &D6DA ;
D6CD CMP #&02 ;
D6CF BNE &D70E ;
D6D1 LDX #&04 ;
D6D3 LDY &DF ;
D6D5 JSR &D482 ;
D6D8 LDX &DF ;
D6DA JSR &D864 ;set a screen address
D6DD LDX &DE ;X=&DE
D6DF JSR &D10F ;check for window violations
D6E2 LSR ;A=A/2
D6E3 BNE &D70E ;if A<>0 then exit
D6E5 BCC &D6E9 ;else if C clear D6E9
D6E7 LDX #&00 ;
D6E9 LDY &DF ;
D6EB SEC ;
D6EC LDA &0300,Y ;
D6EF SBC &0300,X ;
D6F2 STA &DC ;
D6F4 LDA &0301,Y ;
D6F7 SBC &0301,X ;
D6FA STA &DD ;
D6FC LDA #&00 ;
D6FE ASL ;
D6FF ORA &D1 ;
D701 LDY &DC ;
D703 BNE &D719 ;
D705 DEC &DD ;
D707 BPL &D719 ;
D709 STA &D1 ;
D70B JSR &D0F0 ;display a point
D70E LDX &DF ;restore X
D710 PLA ;and A
D711 STA &0301,X ;store it
D714 PLA ;get back A
D715 STA &0300,X ;and store it
D718 RTS ;exit
;
D719 DEC &DC ;
D71B TAX ;
D71C BPL &D6FE ;
D71E STA &D1 ;
D720 JSR &D0F0 ;display a point
D723 LDX &DC ;
D725 INX ;
D726 BNE &D72A ;
D728 INC &DD ;
D72A TXA ;
D72B PHA ;
D72C LSR &DD ;
D72E ROR ;
D72F LDY &0361 ;number of pixels/byte
D732 CPY #&03 ;if 3 mode = goto D73B
D734 BEQ &D73B ;
D736 BCC &D73E ;else if <3 mode 2 goto D73E
D738 LSR &DD ;else rotate bottom bit of &DD
D73A ROR ;into Accumulator
D73B LSR &DD ;rotate bottom bit of &DD
D73D LSR ;into Accumulator
D73E LDY &031A ;Y=line in current graphics cell containing current
;point
D741 TAX ;X=A
D742 BEQ &D753 ;
D744 TYA ;Y=Y-8
D745 SEC ;
D746 SBC #&08 ;
D748 TAY ;
D749 BCS &D74D ;
D74B DEC &D7 ;decrement byte of top line off current graphics cell
D74D JSR &D104 ;display a point
D750 DEX ;
D751 BNE &D744 ;
D753 PLA ;
D754 AND &0361 ;pixels/byte
D757 BEQ &D70E ;
D759 TAX ;
D75A LDA #&00 ;A=0
D75C ASL ;
D75D ORA &0363 ;or with right colour mask
D760 DEX ;
D761 BNE &D75C ;
D763 STA &D1 ;store as byte mask
D765 TYA ;Y=Y-8
D766 SEC ;
D767 SBC #&08 ;
D769 TAY ;
D76A BCS &D76E ;if carry clear
D76C DEC &D7 ;decrement byte of top line off current graphics cell
D76E JSR &D0F3 ;display a point
D771 JMP &D70E ;and exit via D70E
D774 INC &0308,X ;
D777 BNE &D77C ;
D779 INC &0309,X ;
D77C SEC ;
D77D LDA &0300,X ;
D780 SBC &0302,X ;
D783 STA &0300,X ;
D786 LDA &0301,X ;
D789 SBC &0303,X ;
D78C STA &0301,X ;
D78F BPL &D7C1 ;
D791 LDA &030A,X ;
D794 BMI &D7A1 ;
D796 INC &0306,X ;
D799 BNE &D7AC ;
D79B INC &0307,X ;
D79E JMP &D7AC ;
D7A1 LDA &0306,X ;
D7A4 BNE &D7A9 ;
D7A6 DEC &0307,X ;
D7A9 DEC &0306,X ;
D7AC CLC ;
D7AD LDA &0300,X ;
D7B0 ADC &0304,X ;
D7B3 STA &0300,X ;
D7B6 LDA &0301,X ;
D7B9 ADC &0305,X ;
D7BC STA &0301,X ;
D7BF BMI &D791 ;
D7C1 RTS ;
;
;
*************************************************************************
* *
* OSBYTE 135 - READ CHARACTER AT TEXT CURSOR POSITION *
* *
*************************************************************************
D7C2 LDY &0360 ;get number of logical colours
D7C5 BNE &D7DC ;if Y<>0 mode <>7 so D7DC
D7C7 LDA (&D8),Y ;get address of top scan line of current text chr
D7C9 LDY #&02 ;Y=2
D7CB CMP &C4B7,Y ;compare with conversion table
D7CE BNE &D7D4 ;if not equal D7d4
D7D0 LDA &C4B6,Y ;else get next lower byte from table
D7D3 DEY ;Y=Y-1
D7D4 DEY ;Y=Y-1
D7D5 BPL &D7CB ;and if +ve do it again
D7D7 LDY &0355 ;Y=current screen mode
D7DA TAX ;return with character in X
D7DB RTS ;
;
D7DC JSR &D808 ;set up copy of the pattern bytes at text cursor
D7DF LDX #&20 ;X=&20
D7E1 TXA ;A=&20
D7E2 PHA ;Save it
D7E3 JSR &D03E ;get pattern address for code in A
D7E6 PLA ;get back A
D7E7 TAX ;and X
D7E8 LDY #&07 ;Y=7
D7EA LDA &0328,Y ;get byte in pattern copy
D7ED CMP (&DE),Y ;check against pattern source
D7EF BNE &D7F9 ;if not the same D7F9
D7F1 DEY ;else Y=Y-1
D7F2 BPL &D7EA ;and if +ve D7EA
D7F4 TXA ;A=X
D7F5 CPX #&7F ;is X=&7F (delete)
D7F7 BNE &D7D7 ;if not D7D7
D7F9 INX ;else X=X+1
D7FA LDA &DE ;get byte lo address
D7FC CLC ;clear carry
D7FD ADC #&08 ;add 8
D7FF STA &DE ;store it
D801 BNE &D7E8 ;and go back to check next character if <>0
D803 TXA ;A=X
D804 BNE &D7E1 ;if <>0 D7E1
D806 BEQ &D7D7 ;else D7D7
***************** set up pattern copy ***********************************
D808 LDY #&07 ;Y=7
D80A STY &DA ;&DA=Y
D80C LDA #&01 ;A=1
D80E STA &DB ;&DB=A
D810 LDA &0362 ;A=left colour mask
D813 STA &DC ;store an &DC
D815 LDA (&D8),Y ;get a byte from current text character
D817 EOR &0358 ;EOR with text background colour
D81A CLC ;clear carry
D81B BIT &DC ;and check bits of colour mask
D81D BEQ &D820 ;if result =0 then D820
D81F SEC ;else set carry
D820 ROL &DB ;&DB=&DB+Carry
D822 BCS &D82E ;if carry now set (bit 7 DB originally set) D82E
D824 LSR &DC ;else &DC=&DC/2
D826 BCC &D81B ;if carry clear D81B
D828 TYA ;A=Y
D829 ADC #&07 ;ADD ( (7+carry)
D82B TAY ;Y=A
D82C BCC &D810 ;
D82E LDY &DA ;read modified values into Y and A
D830 LDA &DB ;
D832 STA &0328,Y ;store copy
D835 DEY ;and do it again
D836 BPL &D80A ;until 8 bytes copied
D838 RTS ;exit
;
********* pixel reading *************************************************
D839 PHA ;store A
D83A TAX ;X=A
D83B JSR &D149 ;set up positional data
D83E PLA ;get back A
D83F TAX ;X=A
D840 JSR &D85F ;set a screen address after checking for window
;violations
D843 BNE &D85A ;if A<>0 D85A to exit with A=&FF
D845 LDA (&D6),Y ;else get top line of current graphics cell
D847 ASL ;A=A*2 C=bit 7
D848 ROL &DA ;&DA=&DA+2 +C C=bit 7 &DA
D84A ASL &D1 ;byte mask=bM*2 +carry from &DA
D84C PHP ;save flags
D84D BCS &D851 ;if carry set D851
D84F LSR &DA ;else restore &DA with bit '=0
D851 PLP ;pull flags
D852 BNE &D847 ;if Z set D847
D854 LDA &DA ;else A=&DA AND number of colours in current mode -1
D856 AND &0360 ;
D859 RTS ;then exit
;
D85A LDA #&FF ;A=&FF
D85C RTS ;exit
;
********** check for window violations and set up screen address **********
D85D LDX #&20 ;X=&20
D85F JSR &D10F ;
D862 BNE &D85C ;if A<>0 there is a window violation so D85C
D864 LDA &0302,X ;else set up graphics scan line variable
D867 EOR #&FF ;
D869 TAY ;
D86A AND #&07 ;
D86C STA &031A ;in 31A
D86F TYA ;A=Y
D870 LSR ;A=A/2
D871 LSR ;A=A/2
D872 LSR ;A=A/2
D873 ASL ;A=A*2 this gives integer value bit 0 =0
D874 TAY ;Y=A
D875 LDA (&E0),Y ;get high byte of offset from screen RAM start
D877 STA &DA ;store it
D879 INY ;Y=Y+1
D87A LDA (&E0),Y ;get lo byte
D87C LDY &0356 ;get screen map type
D87F BEQ &D884 ;if 0 (modes 0,1,2) goto D884
D881 LSR &DA ;else &DA=&DA/2
D883 ROR ;and A=A/2 +C if set
;so 2 byte offset =offset/2
D884 ADC &0350 ;add screen top left hand corner lo
D887 STA &D6 ;store it
D889 LDA &DA ;get high byte
D88B ADC &0351 ;add top left hi
D88E STA &D7 ;store it
D890 LDA &0301,X ;
D893 STA &DA ;
D895 LDA &0300,X ;
D898 PHA ;
D899 AND &0361 ;and then Add pixels per byte-1
D89C ADC &0361 ;
D89F TAY ;Y=A
D8A0 LDA &C406,Y ;A=&80 /2^Y using look up table
D8A3 STA &D1 ;store it
D8A5 PLA ;get back A
D8A6 LDY &0361 ;Y=&number of pixels/byte
D8A9 CPY #&03 ;is Y=3 (modes 1,6)
D8AB BEQ &D8B2 ;goto D8B2
D8AD BCS &D8B5 ;if mode =1 or 4 D8B5
D8AF ASL ;A/&DA =A/&DA *2
D8B0 ROL &DA ;
D8B2 ASL ;
D8B3 ROL &DA ;
D8B5 AND #&F8 ;clear bits 0-2
D8B7 CLC ;clear carry
D8B8 ADC &D6 ;add A/&DA to &D6/7
D8BA STA &D6 ;
D8BC LDA &DA ;
D8BE ADC &D7 ;
D8C0 BPL &D8C6 ;if result +ve D8C6
D8C2 SEC ;else set carry
D8C3 SBC &0354 ;and subtract screen memory size making it wrap round
D8C6 STA &D7 ;store it in &D7
D8C8 LDY &031A ;get line in graphics cell containing current graphics
D8CB LDA #&00 ;point A=0
D8CD RTS ;And exit
;
D8CE PHA ;Push A
D8CF LDA #&A0 ;A=&A0
D8D1 LDX &026A ;X=number of items in VDU queque
D8D4 BNE &D916 ;if not 0 D916
D8D6 BIT &D0 ;else check VDU status byte
D8D8 BNE &D916 ;if either VDU is disabled or plot to graphics
;cursor enabled then D916
D8DA BVS &D8F5 ;if cursor editing enabled D8F5
D8DC LDA &035F ;else get 6845 register start setting
D8DF AND #&9F ;clear bits 5 and 6
D8E1 ORA #&40 ;set bit 6 to modify last cursor size setting
D8E3 JSR &C954 ;change write cursor format
D8E6 LDX #&18 ;X=&18
D8E8 LDY #&64 ;Y=&64
D8EA JSR &D482 ;set text input cursor from text output cursor
D8ED JSR &CD7A ;modify character at cursor poistion
D8F0 LDA #&02 ;A=2
D8F2 JSR &C59D ;bit 1 of VDU status is set to bar scrolling
D8F5 LDA #&BF ;A=&BF
D8F7 JSR &C5A8 ;bit 6 of VDU status =0
D8FA PLA ;Pull A
D8FB AND #&7F ;clear hi bit (7)
D8FD JSR &C4C0 ;entire VDU routine !!
D900 LDA #&40 ;A=&40
D902 JMP &C59D ;exit
D905 LDA #&20 ;A=&20
D907 BIT &D0 ;if bit 6 cursor editing is set
D909 BVC &D8CB ;
D90B BNE &D8CB ;or bit 5 is set exit &D8CB
D90D JSR &D7C2 ;read a character from the screen
D910 BEQ &D917 ;if A=0 on return exit via D917
D912 PHA ;else store A
D913 JSR &C664 ;perform cursor right
D916 PLA ;restore A
D917 RTS ;and exit
;
D918 LDA #&BD ;zero bits 2 and 6 of VDU status
D91A JSR &C5A8 ;
D91D JSR &C951 ;set normal cursor
D920 LDA #&0D ;A=&0D
D922 RTS ;and return
;this is response of CR as end of edit line
*************************************************************************
* *
* OSBYTE 132 - READ BOTTOM OF DISPLAY RAM *
* *
*************************************************************************
;
D923 LDX &0355 ; Get current screen mode
*************************************************************************
* *
* OSBYTE 133 - READ LOWEST ADDRESS FOR GIVEN MODE *
* *
*************************************************************************
D926 TXA ; A=X
D927 AND #&07 ; Ensure mode 0-7
D929 TAY ; Pass to Y into index into screen size table
D92A LDX &C440,Y ; X=screen size type, 0-4
D92D LDA &C45E,X ; A=high byte of start address for screen type
D930 LDX #&00 ; Returned address is &xx00
D932 BIT &028E ; Check available RAM
D935 BMI &D93E ; If bit 7 set then 32K RAM, so return address
D937 AND #&3F ; 16K RAM, so drop address to bottom 16K
D939 CPY #&04 ; Check screen mode
D93B BCS &D93E ; If mode 4-7, return the address
D93D TXA ; If mode 0-3, return &0000 as not enough memory
; exit
D93E TAY ; Pass high byte of address to Y
D93F RTS ; and return address in YX
\ No newline at end of file
diff --git a/docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/D940 b/docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/D940
new file mode 100644
index 0000000..1c5c51c
--- /dev/null
+++ b/docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/D940
@@ -0,0 +1 @@
+*************************************************************************
*************************************************************************
** **
** SYSTEM STARTUP **
** **
*************************************************************************
*************************************************************************
* DEFAULT PAGE &02 SETTINGS (VECTORS, OSBYTE VARIABLES)
* RESET CODE
*************************************************************************
* *
* DEFAULT SYSTEM SETTINGS FOR PAGE &02 *
* *
*************************************************************************
-------------------------------------------------------------------------
| |
| DEFAULT VECTOR TABLE |
| |
-------------------------------------------------------------------------
D940 DW &E310 ; USERV &200
D942 DW &DC54 ; BRKV &202
D944 DW &DC93 ; IRQ1V &204
D946 DW &DE89 ; IRQ2V &206
D948 DW &DF89 ; CLIV &208
D94A DW &E772 ; BYTEV &20A
D94C DW &E7EB ; WORDV &20C
D94E DW &E0A4 ; WRCHV &20E
D950 DW &DEC5 ; RDCHV &210
D952 DW &F27D ; FILEV &212
D954 DW &F18E ; ARGSV &214
D956 DW &F4C9 ; BGETV &216
D958 DW &F529 ; BPUTV &218
D95A DW &FFA6 ; GBPBV &21A
D95C DW &F3CA ; FINDV &21C
D95E DW &F1B1 ; FSCV &21E
D960 DW &FFA6 ; EVNTV &220
D962 DW &FFA6 ; UPTV &222
D964 DW &FFA6 ; NETV &224
D966 DW &FFA6 ; VDUV &226
D968 DW &EF02 ; KEYV &228
D96A DW &E4B3 ; INSBV &22A
D96C DW &E464 ; REMVB &22C
D96E DW &E1D1 ; CNPV &22E
D970 DW &FFA6 ; IND1V &230
D972 DW &FFA6 ; IND2V &232
D974 DW &FFA6 ; IND3V &234
-------------------------------------------------------------------------
| |
| DEFAULT MOS VARIABLES SETTINGS |
| |
-------------------------------------------------------------------------
* Read/Written by OSBYTE &A6 to &FC
D976 DW &0190 ; OSBYTE variables base address &236 *FX166/7
; (address to add to osbyte number)
D978 DB &0D9F ; Address of extended vectors &238 *FX168/9
D97A DB &02A1 ; Address of ROM information table &23A *FX170/1
D97C DB &F02B ; Address of key translation table &23C *FX172/3
D97E DB &0300 ; Address of VDU variables &23E *FX174/5
D980 DB &00 ; CFS/Vertical sync Timeout counter &240 *FX176
D981 DB &00 ; Current input buffer number &241 *FX177
D982 DB &FF ; Keyboard interrupt processing flag &242 *FX178
D983 DB &00 ; Primary OSHWM (default PAGE) &243 *FX179
D984 DB &00 ; Current OSHWM (PAGE) &244 *FX180
D985 DB &01 ; RS423 input mode &245 *FX181
D986 DB &00 ; Character explosion state &246 *FX182
D987 DB &00 ; CFS/RFS selection, CFS=0 ROM=2 &247 *FX183
D988 DB &00 ; Video ULA control register copy &248 *FX184
D989 DB &00 ; Pallette setting copy &249 *FX185
D98A DB &00 ; ROM number selected at last BRK &24A *FX186
D98B DB &FF ; BASIC ROM number &24B *FX187
D98C DB &04 ; Current ADC channel number &24C *FX188
D98D DB &04 ; Maximum ADC channel number &24D *FX189
D98E DB &00 ; ADC conversion 0/8bit/12bit &24E *FX190
D98F DB &FF ; RS423 busy flag (bit 7=0, busy) &24F *FX191
D990 DB &56 ; ACIA control register copy &250 *FX192
D991 DB &19 ; Flash counter &251 *FX193
D992 DB &19 ; Flash mark period count &252 *FX194
D993 DB &19 ; Flash space period count &253 *FX195
D994 DB &32 ; Keyboard auto-repeat delay &254 *FX196
D995 DB &08 ; Keyboard auto-repeat rate &255 *FX197
D996 DB &00 ; *EXEC file handle &256 *FX198
D997 DB &00 ; *SPOOL file handle &257 *FX199
D998 DB &00 ; Break/Escape handing &258 *FX200
D999 DB &00 ; Econet keyboard disable flag &259 *FX201
D99A DB &20 ; Keyboard status &25A *FX202
; bit 3=1 shift pressed
; bit 4=0 caps lock
; bit 5=0 shift lock
; bit 6=1 control bit
; bit 7=1 shift enabled
D99B DB &09 ; Serial input buffer full threshold &25B *FX203
D99C DB &00 ; Serial input suppression flag &25C *FX204
D99D DB &00 ; Cassette/RS423 flag (0=CFS, &40=RS423) &25D *FX205
D99E DB &00 ; Econet OSBYTE/OSWORD interception flag &25E *FX206
D99F DB &00 ; Econet OSRDCH interception flag &25F *FX207
D9A0 DB &00 ; Econet OSWRCH interception flag &260 *FX208
D9A1 DB &50 ; Speech enable/disable flag (&20/&50) &261 *FX209
D9A2 DB &00 ; Sound output disable flag &262 *FX210
D9A3 DB &03 ; BELL channel number &263 *FX211
D9A4 DB &90 ; BELL amplitude/Envelope number &264 *FX212
D9A5 DB &64 ; BELL frequency &265 *FX213
D9A6 DB &06 ; BELL duration &266 *FX214
D9A7 DB &81 ; Startup message/!BOOT error status &267 *FX215
D9A8 DB &00 ; Length of current soft key string &268 *FX216
D9A9 DB &00 ; Lines printed since last paged halt &269 *FX217
D9AA DB &00 ; 0-(Number of items in VDU queue) &26A *FX218
D9AB DB &09 ; TAB key value &26B *FX219
D9AC DB &1B ; ESCAPE character &26C *FX220
; The following are input buffer code interpretation variables for
; bytes entered into the input buffer with b7 set (is 128-255).
; The standard keyboard only enters characters &80-&BF with the
; function keys, but other characters can be entered, for instance
; via serial input of via other keyboard input systems.
; 0=ignore key
; 1=expand as soft key
; 2-FF add to base for ASCII code
D9AD DB &01 ; C0-&CF &26D *FX221
D9AE DB &D0 ; D0-&DF &26E *FX222
D9AF DB &E0 ; E0-&EF &26F *FX223
D9B0 DB &F0 ; F0-&FF &270 *FX224
D9B1 DB &01 ; 80-&8F function key &271 *FX225
D9B2 DB &80 ; 90-&9F Shift+function key &272 *FX226
D9B3 DB &90 ; A0-&AF Ctrl+function key &273 *FX227
D9B4 DB &00 ; B0-&BF Shift+Ctrl+function key &274 *FX228
D9B5 DB &00 ; ESCAPE key status (0=ESC, 1=ASCII) &275 *FX229
D9B6 DB &00 ; ESCAPE action &276 *FX230
D9B7 DB &FF ; USER 6522 Bit IRQ mask &277 *FX231
D9B8 DB &FF ; 6850 ACIA Bit IRQ bit mask &278 *FX232
D9B9 DB &FF ; System 6522 IRQ bit mask &279 *FX233
D9BA DB &00 ; Tube prescence flag &27A *FX234
D9BB DB &00 ; Speech processor prescence flag &27B *FX235
D9BC DB &00 ; Character destination status &27C *FX236
D9BD DB &00 ; Cursor editing status &27D *FX237
****************** Soft Reset high water mark ***************************
D9BE DB &00 ; unused &27E *FX238
D9BF DB &00 ; unused &27F *FX239
D9C0 DB &00 ; Country code &280 *FX240
D9C1 DB &00 ; User flag &281 *FX241
D9C2 DB &64 ; Serial ULA control register copy &282 *FX242
D9C3 DB &05 ; Current system clock state &283 *FX243
D9C4 DB &FF ; Soft key consitancy flag &284 *FX244
D9C5 DB &01 ; Printer destination &285 *FX245
D9C6 DB &0A ; Printer ignore character &286 *FX246
****************** Hard Reset High water mark ***************************
D9C7 DB &00 ; Break Intercept Vector JMP opcode &288 *FX247
D9C8 DB &00 ; Break Intercept Vector address low &288 *FX248
D9C9 DB &00 ; Break Intercept Vector address high &289 *FX249
D9CA DB &00 ; unused (memory used for VDU) &28A *FX250
D9CB DB &00 ; unused (memory used for display) &28B *FX251
D9CC DB &FF ; Current language ROM number &28C *FX252
****************** Power-On Reset High Water mark ***********************
**************************************************************************
**************************************************************************
** **
** RESET (BREAK) ENTRY POINT **
** **
** Power up Enter with nothing set, 6522 System VIA IER bits **
** 0 to 6 will be clear **
** **
** BREAK IER bits 0 to 6 one or more will be set 6522 IER **
** not reset by BREAK **
** **
**************************************************************************
**************************************************************************
D9CD LDA #&40 ;set NMI first instruction to RTI
D9CF STA &0D00 ;NMI ram start
D9D2 SEI ;disable interrupts just in case
D9D3 CLD ;clear decimal flag
D9D4 LDX #&FF ;reset stack to where it should be
D9D6 TXS ;(&1FF)
D9D7 LDA &FE4E ;read interupt enable register of the system VIA
D9DA ASL ;shift bit 7 into carry
D9DB PHA ;save what's left
D9DC BEQ &D9E7 ;if Power up A=0 so D9E7
D9DE LDA &0258 ;else if BREAK pressed read BREAK Action flags (set by
;*FX200,n)
D9E1 LSR ;divide by 2
D9E2 CMP #&01 ;if (bit 1 not set by *FX200)
D9E4 BNE &DA03 ;then &DA03
D9E6 LSR ;divide A by 2 again (A=0 if *FX200,2/3 else A=n/4
********** clear memory routine ******************************************
D9E7 LDX #&04 ;get page to start clearance from (4)
D9E9 STX &01 ;store it in ZP 01
D9EB STA &00 ;store A at 00
D9ED TAY ;and in Y to set loop counter
D9EE STA (&00),Y ;clear store
D9F0 CMP &01 ;until address &01 =0
D9F2 BEQ &D9FD ;
D9F4 INY ;increment pointer
D9F5 BNE &D9EE ;if not zero loop round again
D9F7 INY ;else increment again (Y=1) this avoids overwriting
;RTI instruction at &D00
D9F8 INX ;increment X
D9F9 INC &01 ;increment &01
D9FB BPL &D9EE ;loop until A=&80 then exit
;note that RAM addressing for 16k loops around so
;&4000=&00 hence checking &01 for 00. This avoids
;overwriting zero page on BREAK
D9FD STX &028E ;writes marker for available RAM 40 =16k,80=32
DA00 STX &0284 ;write soft key consistency flag
**+********** set up system VIA *****************************************
DA03 LDX #&0F ;set PORT B to output on bits 0-3 Input 4-7
DA05 STX &FE42 ;
*************************************************************************
* *
* set addressable latch IC 32 for peripherals via PORT B *
* *
* ;bit 3 set sets addressed latch high adds 8 to VIA address *
* ;bit 3 reset sets addressed latch low *
* *
* Peripheral VIA bit 3=0 VIA bit 3=1 *
* *
* Sound chip Enabled Disabled *
* speech chip (RS) Low High *
* speech chip (WS) Low High *
* Keyboard Auto Scan Disabled Enabled *
* C0 address modifier Low High *
* C1 address modifier Low High *
* Caps lock LED ON OFF *
* Shift lock LED ON OFF *
* *
* C0 & C1 are involved with hardware scroll screen address *
*************************************************************************
;X=&F on entry
DA08 DEX ;loop start
DA09 STX &FE40 ;write latch IC32
DA0C CPX #&09 ;is it 9
DA0E BCS &DA08 ;if so go back and do it again
;X=8 at this point
;Caps lock On, SHIFT lock undetermined
;Keyboard Autoscan on
;sound disabled (may still sound)
DA10 INX ;X=9
DA11 TXA ;A=X
DA12 JSR &F02A ;interrogate keyboard
DA15 CPX #&80 ;for keyboard links 9-2 and CTRL key (1)
DA17 ROR &FC ;rotate MSB into bit 7 of &FC
DA19 TAX ;get back value of X for loop
DA1A DEX ;decrement it
DA1B BNE &DA11 ;and if >0 do loop again
; on exit if Carry set link 3 made
;link 2 = bit 0 of &FC and so on
;if CTRL pressed bit 7 of &FC=1
;X=0
DA1D STX &028D ;clear last BREAK flag
DA20 ROL &FC ;CTRL is now in carry &FC is keyboard links
DA22 JSR &EEEB ;set LEDs carry on entry bit 7 of A on exit
DA25 ROR ;get carry back into carry flag
****** set up page 2 ****************************************************
DA26 LDX #&9C ;
DA28 LDY #&8D ;
DA2A PLA ;get back A from &D9DB
DA2B BEQ &DA36 ;if A=0 power up reset so DA36 with X=&9C Y=&8D
DA2D LDY #&7E ;else Y=&7E
DA2F BCC &DA42 ;and if not CTRL-BREAK DA42 WARM RESET
DA31 LDY #&87 ;else Y=&87 COLD RESET
DA33 INC &028D ;&28D=1
DA36 INC &028D ;&28D=&28D+1
DA39 LDA &FC ;get keyboard links set
DA3B EOR #&FF ;invert
DA3D STA &028F ;and store at &28F
DA40 LDX #&90 ;X=&90
**********: set up page 2 *************************************************
;on entry &28D=0 Warm reset, X=&9C, Y=&7E
;&28D=1 Power up , X=&90, Y=&8D
;&28D=2 Cold reset, X=&9C, Y=&87
DA42 LDA #&00 ;A=0
DA44 CPX #&CE ;zero &200+X to &2CD
DA46 BCC &DA4A ;
DA48 LDA #&FF ;then set &2CE to &2FF to &FF
DA4A STA &0200,X ;
DA4D INX ;
DA4E BNE &DA44 ;
;A=&FF X=0
DA50 STA &FE63 ;set port A of user via to all outputs (printer out)
DA53 TXA ;A=0
DA54 LDX #&E2 ;X=&E2
DA56 STA &00,X ;zero zeropage &E2 to &FF
DA58 INX ;
DA59 BNE &DA56 ;X=0
DA5B LDA &D93F,Y ;copy data from &D93F+Y
DA5E STA &01FF,Y ;to &1FF+Y
DA61 DEY ;until
DA62 BNE &DA5B ;1FF+Y=&200
DA64 LDA #&62 ;A=&62
DA66 STA &ED ;store in &ED
DA68 JSR &FB0A ;set up ACIA
;X=0
************** clear interrupt and enable registers of Both VIAs ********
DA6B LDA #&7F ;
DA6D INX ;
DA6E STA &FE4D,X ;
DA71 STA &FE6D,X ;
DA74 DEX ;
DA75 BPL &DA6E ;
DA77 CLI ;briefly allow interrupts to clear anything pending
DA78 SEI ;disallow again N.B. All VIA IRQs are disabled
DA79 BIT &FC ;if bit 6=1 then JSR &F055 (normally 0)
DA7B BVC &DA80 ;else DA80
DA7D JSR &F055 ;F055 JMP (&FDFE) probably causes a BRK unless
;hardware there redirects it.
;
DA80 LDX #&F2 ;enable interrupts 1,4,5,6 of system VIA
DA82 STX &FE4E ;
;0 Keyboard enabled as needed
;1 Frame sync pulse
;4 End of A/D conversion
;5 T2 counter (for speech)
;6 T1 counter (10 mSec intervals)
;
DA85 LDX #&04 ;set system VIA PCR
DA87 STX &FE4C ;
;CA1 to interrupt on negative edge (Frame sync)
;CA2 Handshake output for Keyboard
;CB1 interrupt on negative edge (end of conversion)
;CB2 Negative edge (Light pen strobe)
;
DA8A LDA #&60 ;set system VIA ACR
DA8C STA &FE4B ;
;disable latching
;disable shift register
;T1 counter continuous interrupts
;T2 counter timed interrupt
DA8F LDA #&0E ;set system VIA T1 counter (Low)
DA91 STA &FE46 ;
;this becomes effective when T1 hi set
DA94 STA &FE6C ;set user VIA PCR
;CA1 interrupt on -ve edge (Printer Acknowledge)
;CA2 High output (printer strobe)
;CB1 Interrupt on -ve edge (user port)
;CB2 Negative edge (user port)
DA97 STA &FEC0 ;set up A/D converter
;Bits 0 & 1 determine channel selected
;Bit 3=0 8 bit conversion bit 3=1 12 bit
DA9A CMP &FE6C ;read user VIA IER if = &0E then DAA2 chip present
DA9D BEQ &DAA2 ;so goto DAA2
DA9F INC &0277 ;else increment user VIA mask to 0 to bar all
;user VIA interrupts
DAA2 LDA #&27 ;set T1 (hi) to &27 this sets T1 to &270E (9998 uS)
DAA4 STA &FE47 ;or 10msec, interrupts occur every 10msec therefore
DAA7 STA &FE45 ;
DAAA JSR &EC60 ;clear the sound channels
DAAD LDA &0282 ;read serial ULA control register
DAB0 AND #&7F ;zero bit 7
DAB2 JSR &E6A7 ;and set up serial ULA
DAB5 LDX &0284 ;get soft key status flag
DAB8 BEQ &DABD ;if 0 (keys OK) then DABD
DABA JSR &E9C8 ;else reset function keys
*************************************************************************
* *
* Check sideways ROMS and make rom list *
* *
*************************************************************************
;X=0
DABD JSR &DC16 ;set up ROM latch and RAM copy to X
DAC0 LDX #&03 ;set X to point to offset in table
DAC2 LDY &8007 ;get copyright offset from ROM
; DF0C = ")C(",0
DAC5 LDA &8000,Y ;get first byte
DAC8 CMP &DF0C,X ;compare it with table byte
DACB BNE &DAFB ;if not the same then goto DAFB
DACD INY ;point to next byte
DACE DEX ;(s)
DACF BPL &DAC5 ;and if still +ve go back to check next byte
;this point is reached if 5 bytes indicate valid
;ROM (offset +4 in (C) string)
*************************************************************************
* Check first 1k of each ROM against higher priority Roms to ensure that*
* there are no matches, if a match found ignore lower priority ROM *
*************************************************************************
DAD1 LDX &F4 ;get RAM copy of ROM No. in X
DAD3 LDY &F4 ;and Y
DAD5 INY ;increment Y to check
DAD6 CPY #&10 ;if ROM 15 is current ROM
DAD8 BCS &DAFF ;if equal or more than 16 goto &DAFF
;to store catalogue byte
DADA TYA ;else put Y in A
DADB EOR #&FF ;invert it
DADD STA &FA ;and store at &FA
DADF LDA #&7F ;store &7F at
DAE1 STA &FB ;&FB to get address &7FFF-Y
DAE3 STY &FE30 ;set new ROM
DAE6 LDA (&FA),Y ;Get byte
DAE8 STX &FE30 ;switch back to previous ROM
DAEB CMP (&FA),Y ;and compare with previous byte called
DAED BNE &DAD5 ;if not the same then go back and do it again
;with next rom up
DAEF INC &FA ;else increment &FA to point to new location
DAF1 BNE &DAE3 ;if &FA<>0 then check next byte
DAF3 INC &FB ;else inc &FB
DAF5 LDA &FB ;and check that it doesn't exceed
DAF7 CMP #&84 ;&84 (1k checked)
DAF9 BCC &DAE3 ;then check next byte(s)
DAFB LDX &F4 ;X=(&F4)
DAFD BPL &DB0C ;if +ve then &DB0C
DAFF LDA &8006 ;get rom type
DB02 STA &02A1,X ;store it in catalogue
DB05 AND #&8F ;check for BASIC (bit 7 not set)
DB07 BNE &DB0C ;if not BASIC the DB0C
DB09 STX &024B ;else store X at BASIC pointer
DB0C INX ;increment X to point to next ROM
DB0D CPX #&10 ;is it 15 or less
DB0F BCC &DABD ;if so goto &DABD for next ROM
OS SERIES V
GEOFF COX
*************************************************************************
* *
* Check SPEECH System *
* *
*************************************************************************
;X=&10
DB11 BIT &FE40 ;if bit 7 low then we have speech system fitted
DB14 BMI &DB27 ;else goto DB27
DB16 DEC &027B ;(027B)=&FF to indicate speech present
DB19 LDY #&FF ;Y=&FF
DB1B JSR &EE7F ;initialise speech generator
DB1E DEX ;via this
DB1F BNE &DB19 ;loop
;X=0
DB21 STX &FE48 ;set T2 timer for speech
DB24 STX &FE49 ;
*********** SCREEN SET UP **********************************************
;X=0
DB27 LDA &028F ;get back start up options (mode)
DB2A JSR &C300 ;then jump to screen initialisation
DB2D LDY #&CA ;Y=&CA
DB2F JSR &E4F1 ;to enter this in keyboard buffer
;this enables the *KEY 10 facility
********* enter BREAK intercept with Carry Clear ************************
DB32 JSR &EAD9 ;check to see if BOOT address is set up, if so
;JMP to it
DB35 JSR &F140 ;set up cassette options
DB38 LDA #&81 ;test for tube to FIFO buffer 1
DB3A STA &FEE0 ;
DB3D LDA &FEE0 ;
DB40 ROR ;put bit 0 into carry
DB41 BCC &DB4D ;if no tube then DB4D
DB43 LDX #&FF ;else
DB45 JSR &F168 ;issue ROM service call &FF
;to initialise TUBE system
DB48 BNE &DB4D ;if not 0 on exit (Tube not initialised) DB4D
DB4A DEC &027A ;else set tube flag to show it's active
DB4D LDY #&0E ;set current value of PAGE
DB4F LDX #&01 ;issue claim absolute workspace call
DB51 JSR &F168 ;via F168
DB54 LDX #&02 ;send private workspace claim call
DB56 JSR &F168 ;via F168
DB59 STY &0243 ;set primary OSHWM
DB5C STY &0244 ;set current OSHWM
DB5F LDX #&FE ;issue call for Tube to explode character set etc.
DB61 LDY &027A ;Y=FF if tube present else Y=0
DB64 JSR &F168 ;and make call via F168
DB67 AND &0267 ;if A=&FE and bit 7 of 0267 is set then continue
DB6A BPL &DB87 ;else ignore start up message
DB6C LDY #&02 ;output to screen
DB6E JSR &DEA9 ;'BBC Computer ' message
DB71 LDA &028D ;0=warm reset, anything else continue
DB74 BEQ &DB82 ;
DB76 LDY #&16 ;by checking length of RAM
DB78 BIT &028E ;
DB7B BMI &DB7F ;and either
DB7D LDY #&11 ;
DB7F JSR &DEA9 ;finishing message with '16k' or '32k'
DB82 LDY #&1B ;and two newlines
DB84 JSR &DEA9 ;
*********: enter BREAK INTERCEPT ROUTINE WITH CARRY SET (call 1)
DB87 SEC ;
DB88 JSR &EAD9 ;look for break intercept jump do *TV etc
DB8B JSR &E9D9 ;set up LEDs in accordance with keyboard status
DB8E PHP ;save flags
DB8F PLA ;and get back in A
DB90 LSR ;zero bits 4-7 and bits 0-2 bit 4 which was bit 7
DB91 LSR ;may be set
DB92 LSR ;
DB93 LSR ;
DB94 EOR &028F ;eor with start-up options which may or may not
DB97 AND #&08 ;invert bit 4
DB99 TAY ;Y=A
DB9A LDX #&03 ;make fs initialisation call, passing boot option in Y
DB9C JSR &F168 ;Eg, RUN, EXEC or LOAD !BOOT file
DB9F BEQ &DBBE ;if a ROM accepts this call then DBBE
DBA1 TYA ;else put Y in A
DBA2 BNE &DBB8 ;if Y<>0 DBB8
DBA4 LDA #&8D ;else set up standard cassete baud rates
DBA6 JSR &F135 ;via &F135
DBA9 LDX #&D2 ;
DBAB LDY #&EA ;
DBAD DEC &0267 ;decrement ignore start up message flag
DBB0 JSR OSCLI ;and execute */!BOOT
DBB3 INC &0267 ;restore start up message flag
DBB6 BNE &DBBE ;if not zero then DBBE
DBB8 LDA #&00 ;else A=0
DBBA TAX ;X=0
DBBB JSR &F137 ;set tape speed
******** Preserve current language on soft RESET ************************
DBBE LDA &028D ;get last RESET Type
DBC1 BNE &DBC8 ;if not soft reset DBC8
DBC3 LDX &028C ;else get current language ROM address
DBC6 BPL &DBE6 ;if +ve (language available) then skip search routine
*************************************************************************
* *
* SEARCH FOR LANGUAGE TO ENTER (Highest priority) *
* *
*************************************************************************
DBC8 LDX #&0F ;set pointer to highest available rom
DBCA LDA &02A1,X ;get rom type from map
DBCD ROL ;put hi-bit into carry, bit 6 into bit 7
DBCE BMI &DBE6 ;if bit 7 set then ROM has a language entry so DBE6
DBD0 DEX ;else search for language until X=&ff
DBD1 BPL &DBCA ;
*************** check if tube present ***********************************
DBD3 LDA #&00 ;if bit 7 of tube flag is set BMI succeeds
DBD5 BIT &027A ;and TUBE is connected else
DBD8 BMI &DC08 ;make error
********* no language error ***********************************************
DBDA BRK ;
DBDB DB &F9 ;error number
DBDC DB 'Language?' ;message
DBE5 BRK ;
DBE6 CLC ;
*************************************************************************
* *
* OSBYTE 142 - ENTER LANGUAGE ROM AT &8000 *
* *
* X=rom number C set if OSBYTE call clear if initialisation *
* *
*************************************************************************
DBE7 PHP ;save flags
DBE8 STX &028C ;put X in current ROM page
DBEB JSR &DC16 ;select that ROM
DBEE LDA #&80 ;A=128
DBF0 LDY #&08 ;Y=8
DBF2 JSR &DEAB ;display text string held in ROM at &8008,Y
DBF5 STY &FD ;save Y on exit (end of language string)
DBF7 JSR OSNEWL ;two line feeds
DBFA JSR OSNEWL ;are output
DBFD PLP ;then get back flags
DBFE LDA #&01 ;A=1 required for language entry
DC00 BIT &027A ;check if tube exists
DC03 BMI &DC08 ;and goto DC08 if it does
DC05 JMP &8000 ;else enter language at &8000
*************************************************************************
* *
* TUBE FOUND, ENTER TUBE SOFTWARE *
* *
*************************************************************************
DC08 JMP &0400 ;enter tube environment
*************************************************************************
* *
* OSRDRM entry point *
* *
* get byte from PHROM or page ROM *
* Y= rom number, address is in &F6/7 *
*************************************************************************
DC0B LDX &F4 ;get current ROM number into X
DC0D STY &F4 ;store new number in &F4
DC0F STY &FE30 ;switch in ROM
DC12 LDY #&00 ;get current PHROM address
DC14 LDA (&F6),Y ;and get byte
******** Set up Sideways Rom latch and RAM copy *************************
;on entry X=ROM number
DC16 STX &F4 ;RAM copy of rom latch
DC18 STX &FE30 ;write to rom latch
DC1B RTS ;and return
\ No newline at end of file
diff --git a/docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/DC1C b/docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/DC1C
new file mode 100644
index 0000000..b319f77
--- /dev/null
+++ b/docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/DC1C
@@ -0,0 +1 @@
+**************************************************************************
**************************************************************************
** **
** MAIN IRQ Entry point **
** **
** **
**************************************************************************
**************************************************************************
;ON ENTRY STACK contains STATUS REGISTER,PCH,PCL ;
DC1C STA &FC ;save A
DC1E PLA ;get back status (flags)
DC1F PHA ;and save again
DC20 AND #&10 ;check if BRK flag set
DC22 BNE &DC27 ;if so goto DC27
DC24 JMP (&0204) ;else JMP (IRQ1V)
*************************************************************************
* *
* BRK handling routine *
* *
*************************************************************************
DC27 TXA ;save X on stack
DC28 PHA ;
DC29 TSX ;get status pointer
DC2A LDA &0103,X ;get Program Counter lo
DC2D CLD ;
DC2E SEC ;set carry
DC2F SBC #&01 ;subtract 2 (1+carry)
DC31 STA &FD ;and store it in &FD
DC33 LDA &0104,X ;get hi byte
DC36 SBC #&00 ;subtract 1 if necessary
DC38 STA &FE ;and store in &FE
DC3A LDA &F4 ;get currently active ROM
DC3C STA &024A ;and store it in &24A
DC3F STX &F0 ;store stack pointer in &F0
DC41 LDX #&06 ;and issue ROM service call 6
DC43 JSR &F168 ;(User BRK) to roms
;at this point &FD/E point to byte after BRK
;ROMS may use BRK for their own purposes
DC46 LDX &028C ;get current language
DC49 JSR &DC16 ;and activate it
DC4C PLA ;get back original value of X
DC4D TAX ;
DC4E LDA &FC ;get back original value of A
DC50 CLI ;allow interrupts
DC51 JMP (&0202) ;and JUMP via BRKV (normally into current language)
*************************************************************************
* *
* DEFAULT BRK HANDLER *
* *
*************************************************************************
DC54 LDY #&00 ;Y=0 to point to byte after BRK
DC56 JSR &DEB1 ;print message
DC59 LDA &0267 ;if BIT 0 set and DISC EXEC error
DC5C ROR ;occurs
DC5D BCS &DC5D ;hang up machine!!!!
DC5F JSR OSNEWL ;else print two newlines
DC62 JSR OSNEWL ;
DC65 JMP &DBB8 ;and set tape speed before entering current
;language
; ACIA IRQ, RxRDY but both Serial and Printer buffers empty
; ---------------------------------------------------------
DC68 SEC
DC69 ROR &024F ; Set b7 of RS423 busy flag
DC6C BIT &0250 ;check bit 7 of current ACIA control register
DC6F BPL &DC78 ;if interrupts NOT enabled DC78
DC71 JSR &E741 ;else E741 to check if serial buffer full
DC74 LDX #&00 ; X=&00 to set RTS low
DC76 BCS &DC7A ;if carry set goto DC7A to transfer data
DC78 LDX #&40 ; X=&40 to set RTS high
DC7A JMP &E17A ; Jump to set ACIA control register
; Serial IRQ and RxRDY - Get byte and store in serial buffer
; ----------------------------------------------------------
DC7D LDY &FE09 ; Read data from ACIA
DC80 AND #&3A ; Check PE:RO:FE:DCD
DC82 BNE &DCB8 ; If any set, jump to generate Serial Error Event
; Serial IRQ and RxRDY, no errors
; -------------------------------
DC84 LDX &025C ; Read RS423 input suppression flag
DC87 BNE &DC92 ; If not 0, jump to ignore
DC89 INX ; X=1, serial input buffer
DC8A JSR &E4F3 ; Put byte in buffer
DC8D JSR &E741 ; Check if serial buffer almost full
DC90 BCC &DC78 ; If almost full, jump to set RTS high
DC92 RTS ; Return
*************************************************************************
* *
* Main IRQ Handling routines, default IRQ1V destination *
* *
*************************************************************************
DC93 CLD ; Clear decimal flag
DC94 LDA &FC ; Get original value of A
DC96 PHA ; Save it
DC97 TXA ; Save X
DC98 PHA ;
DC99 TYA ; and Y
DC9A PHA ;
DC9B LDA #&DE ; Stack return address to &DE82
DC9D PHA
DC9E LDA #&81
DCA0 PHA
DCA1 CLV ; Clear V flag
DCA2 LDA &FE08 ; Read ACIA status register
DCA5 BVS &DCA9 ; b6 set, jump with serial parity error
DCA7 BPL &DD06 ; b7=0, no ACIA interrupt, jump to check VIAs
; ACIA Interrupt or ACIA Parity Error
; -----------------------------------
DCA9 LDX &EA ; Get RS423 timeout counter
DCAB DEX ; Decrement it
DCAC BMI &DCDE ; If 0 or <0, RS423 owns 6850, jump to DCDE
DCAE BVS &DCDD ; If &41..&80, nobody owns 6850, jump to exit
DCB0 JMP &F588 ; CFS owns 6850, jump to read ACIA in CFS routines
; ACIA Data Carrier Detect
; ------------------------
DCB3 LDY &FE09 ; Read ACIA data
DCB6 ROL A ;
DCB7 ASL A ; Rotate ACIA Status back
DCB8 TAX ; X=ACIA Status
DCB9 TYA ; A=ACIA Data
DCBA LDY #&07 ; Y=07 for RS423 Error Event
DCBC JMP &E494 ; Jump to issue event
; ACIA IRQ, TxRDY - Send a byte
; -----------------------------
DCBF LDX #&02
DCC1 JSR &E460 ; Read from Serial output buffer
DCC4 BCC &DCD6 ; Buffer is not empty, jump to send byte
DCC6 LDA &0285 ; Read printer destination
DCC9 CMP #&02 ; Is it serial printer??
DCCB BNE &DC68 ; Serial buffer empty, not Serial printer, jump to ... DC68
DCCD INX ; X=3 for Printer buffer
DCCE JSR &E460 ; Read from Printer buffer
DCD1 ROR &02D2 ; Copy Byte Fetched/Not fetched into Printer Buffer full flag
DCD4 BMI &DC68 ; Printer buffer was empty, so jump to ... DC68
DCD6 STA &FE09 ; Send byte to ACIA
DCD9 LDA #&E7 ; Set timeout counter to &E7
DCDB STA &EA ; Serial owns 6850 for 103 more calls
DCDD RTS ; Exit IRQ
; RS423 owns 6850, PE or RxRDY interupt occured
; ---------------------------------------------
; On entry, A contains ACIA status
;
DCDE AND &0278 ; AND with ACIA IRQ mask (normally &FF)
DCE1 LSR A ; Move RxRDY into Carry
DCE2 BCC &DCEB ; If no RxData, jump to check DCD and TxRDY
;
; Data in RxData, check for errors
;
DCE4 BVS &DCEB ; If IRQ=1 (now in b6) RxIRQ must have occured, so jump to DCEB
;
; RxData but no RxIRQ, check that IRQs are actually disabled
;
DCE6 LDY &0250 ; Get ACIA control setting
DCE9 BMI &DC7D ; If bit 7=1, IRQs enabled so jump to read byte and insert into buffer
;
; DCE9 -> RxData, no RxIRQ, IRQs disabled
; DCE4 -> RxData and RxIRQ
; DCE2 -> No RxData
;
; Check TxRDY and DCD, if neither set, send a Serial Error Event
; --------------------------------------------------------------
DCEB LSR A ; Move TxRDY into Carry
DCEC ROR A ; Rotate TxRDY into b7 and DCD into Carry
DCED BCS &DCB3 ; If Data Carrier Detected, jump to DCB3
DCEF BMI &DCBF ; If TxRDY (now in b7) jump to to DCBF to send a byte
DCF1 BVS &DCDD ; b6 should always be zero by now, but if set, then jump to exit
; Issue Unknown Interupt service call
; ===================================
DCF3 LDX #&05
DCF5 JSR &F168 ; Issue service call 5, 'Unknown Interrupt'
DCF8 BEQ &DCDD ; If claimed, then jump to exit
DCFA PLA ; Otherwise drop return address from stack
DCFB PLA ;
DCFC PLA ; And restore registers
DCFD TAY ;
DCFE PLA ;
DCFF TAX ;
DD00 PLA ;
DD01 STA &FC ; Store A in IRQA
DD03 JMP (&0206) ; And pass the IRQ in to IRQ2V
*************************************************************************
* *
* VIA INTERUPTS ROUTINES *
* *
*************************************************************************
DD06 LDA &FE4D ; Read System VIA interrupt flag register
DD09 BPL &DD47 ; No System VIA interrupt, jump to check User VIA
; System VIA interupt
;
DD0B AND &0279 ; Mask with System VIA bit mask
DD0E AND &FE4E ; and interrupt enable register
DD11 ROR ; Rotate to check for CA1 interupt (frame sync)
DD12 ROR ;
DD13 BCC &DD69 ; No CA1 (frame sync), jump to check speech
; System VIA CA1 interupt (Frame Sync)
;
DD15 DEC &0240 ;decrement vertical sync counter
DD18 LDA &EA ;A=RS423 Timeout counter
DD1A BPL &DD1E ;if +ve then DD1E
DD1C INC &EA ;else increment it
DD1E LDA &0251 ;load flash counter
DD21 BEQ &DD3D ;if 0 then system is not in use, ignore it
DD23 DEC &0251 ;else decrement counter
DD26 BNE &DD3D ;and if not 0 go on past reset routine
DD28 LDX &0252 ;else get mark period count in X
DD2B LDA &0248 ;current VIDEO ULA control setting in A
DD2E LSR ;shift bit 0 into C to check if first colour
DD2F BCC &DD34 ;is effective if so C=0 jump to DD34
DD31 LDX &0253 ;else get space period count in X
DD34 ROL ;restore bit
DD35 EOR #&01 ;and invert it
DD37 JSR &EA00 ;then change colour
DD3A STX &0251 ;&0251=X resetting the counter
DD3D LDY #&04 ;Y=4 and call E494 to check and implement vertical
DD3F JSR &E494 ;sync event (4) if necessary
DD42 LDA #&02 ;A=2
DD44 JMP &DE6E ;clear interrupt 1 and exit
*************************************************************************
* *
* PRINTER INTERRUPT USER VIA 1 *
* *
*************************************************************************
DD47 LDA &FE6D ; Read User VIA interrupt flag register
DD4A BPL &DCF3 ; No User VIA interrupt, jump to pass to ROMs
; User VIA interupt
;
DD4C AND &0277 ;else check for USER IRQ 1
DD4F AND &FE6E ;
DD52 ROR ;
DD53 ROR ;
DD54 BCC &DCF3 ;if bit 1=0 the no interrupt 1 so DCF3
DD56 LDY &0285 ;else get printer type
DD59 DEY ;decrement
DD5A BNE &DCF3 ;if not parallel then DCF3
DD5C LDA #&02 ;reset interrupt 1 flag
DD5E STA &FE6D ;
DD61 STA &FE6E ;disable interrupt 1
DD64 LDX #&03 ;and output data to parallel printer
DD66 JMP &E13A ;
*************************************************************************
* *
* SYSTEM INTERRUPT 5 Speech *
* *
*************************************************************************
DD69 ROL ; Rotate bit 5 into bit 7
DD6A ROL ;
DD6B ROL ;
DD6C ROL ;
DD6D BPL &DDCA ; Not a Timer 2 interrupt, jump to check timers
; System VIA Timer 2 interupt - Speech interupt
;
DD6F LDA #&20 ; Prepare to clear VIA interupt
DD71 LDX #&00
DD73 STA &FE4D ; Clear VIA interupt
DD76 STX &FE49 ; Zero high byte of T2 Timer
DD79 LDX #&08 ; X=8 for Speech buffer
DD7B STX &FB ; Prepare to loop up to four times for Speak from RAM
;
DD7D JSR &E45B ; Examine Speech buffer
DD80 ROR &02D7 ; Shift carry into bit 7
DD83 BMI &DDC9 ; Buffer empty, so exit
DD85 TAY ; Buffer not empty, A=first byte waiting
DD86 BEQ &DD8D ; Waiting byte=&00 (Speak, no reset), skip past
DD88 JSR &EE6D ;control speech chip
DD8B BMI &DDC9 ;if negative exit
DD8D JSR &E460 ; Fetch Speech command byte from buffer
DD90 STA &F5 ; Store it
DD92 JSR &E460 ; Fetch Speech word high byte from buffer
DD95 STA &F7 ; Store it
DD97 JSR &E460 ; Fetch Speech word low byte from buffer
DD9A STA &F6 ; Store it, giving &F6/7=address to be accessed
DD9C LDY &F5 ; Y=Speech command byte
DD9E BEQ &DDBB ; SOUND &FF00 - Speak from RAM, no reset
DDA0 BPL &DDB8 ; SOUND &FF01-&FF7F - Speak from RAM, with reset
DDA2 BIT &F5 ; Check bit 6 of Speech command
DDA4 BVS &DDAB ; SOUND &FFC0-&FFFF - Speak word number
; SOUND &FF80-&FFBF - Speak from absolute address
; &F5=command &80-&BF (b0-b3=PHROM number), &F6/7=address
;
DDA6 JSR &EEBB ; Write address to speech processor
DDA9 BVC &DDB2 ; Skip forward to speak from selected address
; SOUND &FFC0-&FFFF - Speak word number
; &F5=command &C0-&FF (b0-b3=PHROM number), &F6/7=word number
;
DDAB ASL &F6 ; Multiply address by 2 to index into word table
DDAD ROL &F7 ;
DDAF JSR &EE3B ; Read address from specified PHROM
; Speak from PHROM address
; By now, the address in the PHROM specified in Command b0-b3 has been set
; to the start of the speech data to be voiced.
;
DDB2 LDY &0261 ; Fetch command code, usually &50=Speak or &00=Nop
DDB5 JMP &EE7F ; Jump to send command to speak from current address
; SOUND &FF01-&FF7F - Speak from RAM with reset
; Y=Speech command byte, &F6/7=Speech data
; Use SOUND &FF60 to send Speak External command
;
DDB8 JSR &EE7F ; Send command byte to Speech processor
; SOUND &FF00 - Speak from RAM without reset
; &6/7=Speech data
;
DDBB LDY &F6
DDBD JSR &EE7F ; Send Speech data low byte
DDC0 LDY &F7
DDC2 JSR &EE7F ; Send Speech data high byte
DDC5 LSR &FB ; Shift loop counter
DDC7 BNE &DD7D ; Loop to send up to four byte-pairs
DDC9 RTS
***********************************************************************
* *
* SYSTEM INTERRUPT 6 10mS Clock *
* *
*************************************************************************
DDCA BCC &DE47 ;bit 6 is in carry so if clear there is no 6 int
;so go on to DE47
DDCC LDA #&40 ;Clear interrupt 6
DDCE STA &FE4D ;
;UPDATE timers routine, There are 2 timer stores &292-6 and &297-B
;these are updated by adding 1 to the current timer and storing the
;result in the other, the direction of transfer being changed each
;time of update. This ensures that at least 1 timer is valid at any call
;as the current timer is only read. Other methods would cause inaccuracies
;if a timer was read whilst being updated.
DDD1 LDA &0283 ;get current system clock store pointer (5,or 10)
DDD4 TAX ;put A in X
DDD5 EOR #&0F ;and invert lo nybble (5 becomes 10 and vv)
DDD7 PHA ;store A
DDD8 TAY ;put A in Y
;Carry is always set at this point
DDD9 LDA &0291,X ;get timer value
DDDC ADC #&00 ;update it
DDDE STA &0291,Y ;store result in alternate
DDE1 DEX ;decrement X
DDE2 BEQ &DDE7 ;if 0 exit
DDE4 DEY ;else decrement Y
DDE5 BNE &DDD9 ;and go back and do next byte
DDE7 PLA ;get back A
DDE8 STA &0283 ;and store back in clock pointer (i.e. inverse previous
;contents)
DDEB LDX #&05 ;set loop pointer for countdown timer
DDED INC &029B,X ;increment byte and if
DDF0 BNE &DDFA ;not 0 then DDFA
DDF2 DEX ;else decrement pointer
DDF3 BNE &DDED ;and if not 0 do it again
DDF5 LDY #&05 ;process EVENT 5 interval timer
DDF7 JSR &E494 ;
DDFA LDA &02B1 ;get byte of inkey countdown timer
DDFD BNE &DE07 ;if not 0 then DE07
DDFF LDA &02B2 ;else get next byte
DE02 BEQ &DE0A ;if 0 DE0A
DE04 DEC &02B2 ;decrement 2B2
DE07 DEC &02B1 ;and 2B1
DE0A BIT &02CE ;read bit 7 of envelope processing byte
DE0D BPL &DE1A ;if 0 then DE1A
DE0F INC &02CE ;else increment to 0
DE12 CLI ;allow interrupts
DE13 JSR &EB47 ;and do routine sound processes
DE16 SEI ;bar interrupts
DE17 DEC &02CE ;DEC envelope processing byte back to 0
DE1A BIT &02D7 ;read speech buffer busy flag
DE1D BMI &DE2B ;if set speech buffer is empty, skip routine
DE1F JSR &EE6D ;update speech system variables
DE22 EOR #&A0 ;
DE24 CMP #&60 ;
DE26 BCC &DE2B ;if result >=&60 DE2B
DE28 JSR &DD79 ;else more speech work
DE2B BIT &D9B7 ;set V and C
DE2E JSR &DCA2 ;check if ACIA needs attention
DE31 LDA &EC ;check if key has been pressed
DE33 ORA &ED ;
DE35 AND &0242 ;(this is 0 if keyboard is to be ignored, else &FF)
DE38 BEQ &DE3E ;if 0 ignore keyboard
DE3A SEC ;else set carry
DE3B JSR &F065 ;and call keyboard
DE3E JSR &E19B ;check for data in user defined printer channel
DE41 BIT &FEC0 ;if ADC bit 6 is set ADC is not busy
DE44 BVS &DE4A ;so DE4A
DE46 RTS ;else return
;
*************************************************************************
* *
* SYSTEM INTERRUPT 4 ADC end of conversion *
* *
*************************************************************************
DE47 ROL ;put original bit 4 from FE4D into bit 7 of A
DE48 BPL &DE72 ;if not set DE72
DE4A LDX &024C ;else get current ADC channel
DE4D BEQ &DE6C ;if 0 DE6C
DE4F LDA &FEC2 ;read low data byte
DE52 STA &02B5,X ;store it in &2B6,7,8 or 9
DE55 LDA &FEC1 ;get high data byte
DE58 STA &02B9,X ;and store it in hi byte
DE5B STX &02BE ;store in Analogue system flag marking last channel
DE5E LDY #&03 ;handle event 3 conversion complete
DE60 JSR &E494 ;
DE63 DEX ;decrement X
DE64 BNE &DE69 ;if X=0
DE66 LDX &024D ;get highest ADC channel preseny
DE69 JSR &DE8F ;and start new conversion
DE6C LDA #&10 ;reset interrupt 4
DE6E STA &FE4D ;
DE71 RTS ;and return
*************************************************************************
* *
* SYSTEM INTERRUPT 0 Keyboard *
* *
*************************************************************************
;
DE72 ROL ;get original bit 0 in bit 7 position
DE73 ROL ;
DE74 ROL ;
DE75 ROL ;
DE76 BPL &DE7F ;if bit 7 clear not a keyboard interrupt
DE78 JSR &F065 ;else scan keyboard
DE7B LDA #&01 ;A=1
DE7D BNE &DE6E ;and off to reset interrupt and exit
DE7F JMP &DCF3 ;
************** exit routine *********************************************
DE82 PLA ;restore registers
DE83 TAY ;
DE84 PLA ;
DE85 TAX ;
DE86 PLA ;
DE87 STA &FC ;store A
*************************************************************************
* *
* IRQ2V default entry *
*************************************************************************
DE89 LDA &FC ;get back original value of A
DE8B RTI ;and return to calling routine
*************************************************************************
* *
* OSBYTE 17 Start conversion *
* *
*************************************************************************
;
DE8C STY &02BE ;set last channel to finish conversion
DE8F CPX #&05 ;if X<4 then
DE91 BCC &DE95 ;DE95
DE93 LDX #&04 ;else X=4
DE95 STX &024C ;store it as current ADC channel
DE98 LDY &024E ;get conversion type
DE9B DEY ;decrement
DE9C TYA ;A=Y
DE9D AND #&08 ;and it with 08
DE9F CLC ;clear carry
DEA0 ADC &024C ;add to current ADC
DEA3 SBC #&00 ;-1
DEA5 STA &FEC0 ;store to the A/D control panel
DEA8 RTS ;and return
;
DEA9 LDA #&C3 ;point to start of string @&C300
DEAB STA &FE ;store it
DEAD LDA #&00 ;point to lo byte
DEAF STA &FD ;store it and start loop@
DEB1 INY ;print character in string
DEB2 LDA (&FD),Y ;pointed to by &FD/E
DEB4 JSR OSASCI ;print it expanding Carriage returns
DEB7 TAX ;store A in X
DEB8 BNE &DEB1 ;and loop again if not =0
DEBA RTS ;else exit
*********** OSBYTE 129 TIMED ROUTINE ******************************
;ON ENTRY TIME IS IN X,Y
DEBB STX &02B1 ;store time in INKEY countdown timer
DEBE STY &02B2 ;which is decremented every 10ms
DEC1 LDA #&FF ;A=&FF to flag timed wait
DEC3 BNE &DEC7 ;goto DEC7
**************************************************************************
**************************************************************************
** **
** OSRDCH Default entry point **
** **
** RDCHV entry point read a character **
** **
**************************************************************************
**************************************************************************
DEC5 LDA #&00 ;A=0 to flag wait forever
DEC7 STA &E6 ;store entry value of A
DEC9 TXA ;save X and Y
DECA PHA ;
DECB TYA ;
DECC PHA ;
DECD LDY &0256 ;get *EXEC file handle
DED0 BEQ &DEE6 ;if 0 (not open) then DEE6
DED2 SEC ;set carry
DED3 ROR &EB ;set bit 7 of CFS active flag to prevent clashes
DED5 JSR OSBGET ;get a byte from the file
DED8 PHP ;push processor flags to preserve carry
DED9 LSR &EB ;restore &EB
DEDB PLP ;get back flags
DEDC BCC &DF03 ;and if carry clear, character found so exit via DF03
DEDE LDA #&00 ;else A=00 as EXEC file empty
DEE0 STA &0256 ;store it in exec file handle
DEE3 JSR OSFIND ;and close file via OSFIND
DEE6 BIT &FF ;check ESCAPE flag, if bit 7 set Escape pressed
DEE8 BMI &DF00 ;so off to DF00
DEEA LDX &0241 ;else get current input buffer number
DEED JSR &E577 ;get a byte from input buffer
DEF0 BCC &DF03 ;and exit if character returned
DEF2 BIT &E6 ;(E6=0 or FF)
DEF4 BVC &DEE6 ;if entry was OSRDCH not timed keypress, so go back and
;do it again i.e. perform GET function
DEF6 LDA &02B1 ;else check timers
DEF9 ORA &02B2 ;
DEFC BNE &DEE6 ;and if not zero go round again
DEFE BCS &DF05 ;else exit
DEF0 .. BCC &DF03
DEF2 $� BIT &E6
DEF4 P� BVC &DEE6
DEF6 ��. LDA &02B1
DEF9 .�. ORA &02B2
DEFC �� BNE &DEE6
DEFE �. BCS &DF05
DF00 8 SEC
DF01 �. LDA #&1B
DF03 .� STA &E6
DF05 h PLA
DF06 � TAY
DF07 h PLA
DF08 � TAX
DF09 �� LDA &E6
DF0B ` RTS
\ No newline at end of file
diff --git a/docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/DF0C b/docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/DF0C
new file mode 100644
index 0000000..b273fa3
--- /dev/null
+++ b/docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/DF0C
@@ -0,0 +1,512 @@
+**** STRINGS ****
+
+DF0C DB ')C)',0 ; Copyright string match
+
+**** COMMMANDS ****
+; Command Address Call goes to
+DF10 DB '.',E0,31,05 ; *. &E031, A=5 FSCV, XY=>String
+DF14 DB 'FX',E3,42,FF ; *FX &E342, A=&FF Number paramters
+DF19 DB 'BASIC',E0,18,00 ; *BASIC &E018, A=0 XY=>String
+DF21 DB 'CAT',E0,31,05 ; *CAT &E031, A=5 FSCV, XY=>String
+DF27 DB 'CODE',E3,48,88 ; *CODE &E348, A=&88 OSBYTE &88
+DF2E DB 'EXEC',F6,8D,00 ; *EXEC &F68D, A=0 XY=>String
+DF35 DB 'HELP',F0,B9,FF ; *HELP &F0B9, A=&FF F2/3=>String
+DF3C DB 'KEY',E3,27,FF ; *KEY &E327, A=&FF F2/3=>String
+DF42 DB 'LOAD',E2,3C,00 ; *LOAD &E23C, A=0 XY=>String
+DF49 DB 'LINE',E6,59,01 ; *LINE &E659, A=1 USERV, XY=>String
+DF50 DB 'MOTOR',E3,48,89 ; *MOTOR &E348, A=&89 OSBYTE
+DF58 DB 'OPT',E3,48,8B ; *OPT &E348, A=&8B OSBYTE
+DF5E DB 'RUN',E0,31,04 ; *RUN &E031, A=4 FSCV, XY=>String
+DF64 DB 'ROM',E3,48,8D ; *ROM &E348, A=&8D OSBYTE
+DF6A DB 'SAVE',E2,3E,00 ; *SAVE &E23E, A=0 XY=>String
+DF70 DB 'SPOOL',E2,81,00 ; *SPOOL &E281, A=0 XY=>String
+DF79 DB 'TAPE',E3,48,8C ; *TAPE &E348, A=&8C OSBYTE
+DF80 DB 'TV',E3,48,90 ; *TV &E348, A=&90 OSBYTE
+DF85 DB E0 ; Table end marker
+
+; Command routines are entered with XY=>command tail, A=table parameter,
+; &F2/3,&E6=>start of command string
+; If table parameter if <&80, F2/3,Y converted to XY before entering
+
+
+DF86 31 03 1. AND (&03),Y
+DF88 00 . BRK
+
+*************************************************************************
+* *
+* CLI - COMMAND LINE INTERPRETER *
+* *
+* ENTRY: XY=>Command line *
+* EXIT: All registers corrupted *
+* [ A=13 - unterminated string ]
+*************************************************************************
+;
+DF89 STX &F2 ; Store XY in &F2/3
+DF8B STY &F3
+DF8D LDA #&08
+DF8F JSR &E031 ; Inform filing system CLI being processed
+DF92 LDY #&00 ; Check the line is correctly terminated
+DF94 LDA (&F2),Y
+DF96 CMP #&0D ; Loop until CR is found
+DF98 BEQ &DF9E
+DF9A INY ; Move to next character
+DF9B BNE &DF94 ; Loop back if less than 256 bytes long
+DF9D RTS ; Exit if string > 255 characters
+
+; String is terminated - skip prepended spaces and '*'s
+DF9E LDY #&FF
+DFA0 JSR &E039 ; Skip any spaces
+DFA3 BEQ &E017 ; Exit if at CR
+DFA5 CMP #&2A ; Is this character '*'?
+DFA7 BEQ &DFA0 ; Loop back to skip it, and check for spaces again
+
+DFA9 JSR &E03A ; Skip any more spaces
+DFAC BEQ &E017 ; Exit if at CR
+DFAE CMP #&7C ; Is it '|' - a comment?
+DFB0 BEQ &E017 ; Exit if so
+DFB2 CMP #&2F ; Is it '/' - pass straight to filing system?
+DFB4 BNE &DFBE ; Jump forward if not
+DFB6 INY ; Move past the '/'
+DFB7 JSR &E009 ; Convert &F2/3,Y->XY, ignore returned A
+DFBA LDA #&02 ; 2=RunSlashCommand
+DFBC BNE &E031 ; Jump to pass to FSCV
+;
+; Look command up in command table
+DFBE 84 E6 .� STY &E6 ; Store offset to start of command
+DFC0 A2 00 �. LDX #&00
+DFC2 F0 13 �. BEQ &DFD7
+;
+DFC4 5D 10 DF ].� EOR &DF10,X
+DFC7 29 DF )� AND #&DF
+DFC9 D0 17 �. BNE &DFE2
+DFCB C8 � INY
+DFCC 18 . CLC
+;
+DFCD B0 25 �% BCS &DFF4
+DFCF E8 � INX
+DFD0 B1 F2 �� LDA (&F2),Y
+DFD2 20 E3 E4 �� JSR &E4E3
+DFD5 90 ED .� BCC &DFC4
+;
+DFD7 BD 10 DF �.� LDA &DF10,X
+DFDA 30 16 0. BMI &DFF2
+DFDC B1 F2 �� LDA (&F2),Y
+DFDE C9 2E �. CMP #&2E
+DFE0 F0 04 �. BEQ &DFE6
+DFE2 18 . CLC
+DFE3 A4 E6 �� LDY &E6
+DFE5 88 . DEY
+DFE6 C8 � INY
+DFE7 E8 � INX
+DFE8 E8 � INX
+DFE9 BD 0E DF �.� LDA &DF0E,X
+DFEC F0 33 �3 BEQ &E021
+DFEE 10 F8 .� BPL &DFE8
+DFF0 30 DB 0� BMI &DFCD
+;
+DFF2 E8 � INX
+DFF3 E8 � INX
+;
+DFF4 CA � DEX
+DFF5 CA � DEX
+DFF6 48 H PHA
+DFF7 BD 11 DF �.� LDA &DF11,X
+DFFA 48 H PHA
+DFFB 20 3A E0 :� JSR &E03A
+DFFE 18 . CLC
+DFFF 08 . PHP
+E000 20 04 E0 .� JSR &E004
+E003 40 @ RTI ; Jump to routine
+
+E004 LDA &DF12,X ; Get table parameter
+E007 BMI &E017 ; If >=&80, number follow
+; ; else string follows
+
+E009 TYA ; Pass Y line offset to A for later
+E00A LDY &DF12,X ; Get looked-up parameter from table
+
+; Convert &F2/3,A to XY, put Y in A
+E00D 18 . CLC
+E00E 65 F2 e� ADC &F2
+E010 AA � TAX
+E011 98 . TYA ; Pass supplied Y into A
+E012 A4 F3 �� LDY &F3
+E014 90 01 .. BCC &E017
+E016 C8 � INY
+;
+E017 60 ` RTS
+
+
+; *BASIC
+E018 LDX &024B ; Get Basic rom number
+E01B BMI &E021 ; If none set, jump to pass command on
+E01D SEC ; Set Carry = not entering from RESET
+E01E JMP &DBE7 ; Enter language rom in X
+
+; Pass command on to other roms and to filing system
+E021 LDY &E6 ; Restore pointer to start of command
+E023 LDX #&04 ; 4=UnknownCommand
+E025 JSR &F168 ; Pass to sideways roms
+E028 BEQ &E017 ; If claimed, exit
+E02A LDA &E6 ; Restore pointer to start of command
+E02C JSR &E00D ; Convert &F2/3,A to XY, ignore returned A
+E02F LDA #&03 ; 3=PassCommandToFilingSystem
+
+; Pass to current filing system
+E031 JMP (&021E)
+
+E034 0A . ASL A
+E035 29 01 ). AND #&01
+E037 10 F8 .� BPL &E031
+
+; Skip spaces
+E039 C8 � INY
+E03A B1 F2 �� LDA (&F2),Y
+E03C C9 20 � CMP #&20
+E03E F0 F9 �� BEQ &E039
+E040 C9 0D �. CMP #&0D
+E042 60 ` RTS
+
+;
+E043 90 F5 .� BCC &E03A
+E045 20 3A E0 :� JSR &E03A
+E048 C9 2C �, CMP #&2C
+E04A D0 F4 �� BNE &E040
+E04C C8 � INY
+E04D 60 ` RTS
+
+;
+E04E 20 3A E0 :� JSR &E03A
+E051 20 7D E0 }� JSR &E07D
+E054 90 37 .7 BCC &E08D
+E056 85 E6 .� STA &E6
+E058 20 7C E0 |� JSR &E07C
+E05B 90 19 .. BCC &E076
+E05D AA � TAX
+E05E A5 E6 �� LDA &E6
+E060 0A . ASL A
+E061 B0 2A �* BCS &E08D
+E063 0A . ASL A
+E064 B0 27 �' BCS &E08D
+E066 65 E6 e� ADC &E6
+E068 B0 23 �# BCS &E08D
+E06A 0A . ASL A
+E06B B0 20 � BCS &E08D
+E06D 85 E6 .� STA &E6
+E06F 8A . TXA
+E070 65 E6 e� ADC &E6
+E072 B0 19 �. BCS &E08D
+E074 90 E0 .� BCC &E056
+E076 A6 E6 �� LDX &E6
+E078 C9 0D �. CMP #&0D
+E07A 38 8 SEC
+E07B 60 ` RTS
+
+E07C C8 � INY
+E07D B1 F2 �� LDA (&F2),Y
+E07F C9 3A �: CMP #&3A
+E081 B0 0A �. BCS &E08D
+E083 C9 30 �0 CMP #&30
+E085 90 06 .. BCC &E08D
+E087 29 0F ). AND #&0F
+E089 60 ` RTS
+
+E08A 20 45 E0 E� JSR &E045
+E08D 18 . CLC
+E08E 60 ` RTS
+
+E08F 20 7D E0 }� JSR &E07D
+E092 B0 0E �. BCS &E0A2
+E094 29 DF )� AND #&DF
+E096 C9 47 �G CMP #&47
+E098 B0 F0 �� BCS &E08A
+E09A C9 41 �A CMP #&41
+E09C 90 EC .� BCC &E08A
+E09E 08 . PHP
+E09F E9 37 �7 SBC #&37
+E0A1 28 ( PLP
+E0A2 C8 � INY
+E0A3 60 ` RTS
+
+; WRCH control routine
+; ====================
+E0A4 48 H PHA ; Save all registers
+E0A5 8A . TXA
+E0A6 48 H PHA
+E0A7 98 . TYA
+E0A8 48 H PHA
+E0A9 BA � TSX
+E0AA BD 03 01 �.. LDA &0103,X ; Get A back from stack
+E0AD 48 H PHA ; Save A
+E0AE 2C 60 02 ,`. BIT &0260 ; Check OSWRCH interception flag
+E0B1 10 08 .. BPL &E0BB ; Not set, skip interception call
+E0B3 A8 � TAY ; Pass character to Y
+E0B4 A9 04 �. LDA #&04 ; A=4 for OSWRCH call
+E0B6 20 7E E5 ~� JSR &E57E ; Call interception code
+E0B9 B0 52 �R BCS &E10D ; If claimed, jump past to exit
+
+E0BB 18 . CLC ; Prepare to not send this to printer
+E0BC A9 02 �. LDA #&02 ; Check output destination
+E0BE 2C 7C 02 ,|. BIT &027C ; Is VDU driver disabled?
+E0C1 D0 05 �. BNE &E0C8 ; Yes, skip past VDU driver
+E0C3 68 h PLA ; Get character back
+E0C4 48 H PHA ; Resave character
+E0C5 20 C0 C4 �� JSR &C4C0 ; Call VDU driver
+ ; On exit, C=1 if character to be sent to printer
+
+E0C8 A9 08 �. LDA #&08 ; Check output destination
+E0CA 2C 7C 02 ,|. BIT &027C ; Is printer seperately enabled?
+E0CD D0 02 �. BNE &E0D1 ; Yes, jump to call printer driver
+E0CF 90 05 .. BCC &E0D6 ; Carry clear, don't sent to printer
+E0D1 68 h PLA ; Get character back
+E0D2 48 H PHA ; Resave character
+E0D3 20 14 E1 .� JSR &E114 ; Call printer driver
+
+E0D6 AD 7C 02 �|. LDA &027C ; Check output destination
+E0D9 6A j ROR A ; Is serial output enabled?
+E0DA 90 1B .. BCC &E0F7 ; No, skip past serial output
+E0DC A4 EA �� LDY &EA ; Get serial timout counter
+E0DE 88 . DEY ; Decrease counter
+E0DF 10 16 .. BPL &E0F7 ; Timed out, skip past serial code
+E0E1 68 h PLA ; Get character back
+E0E2 48 H PHA ; Resace character
+E0E3 08 . PHP ; Save IRQs
+E0E4 78 x SEI ; Disable IRQs
+E0E5 A2 02 �. LDX #&02 ; X=2 for serial output buffer
+E0E7 48 H PHA ; Save character
+E0E8 20 5B E4 [� JSR &E45B ; Examine serial output buffer
+E0EB 90 03 .. BCC &E0F0 ; Buffer not full, jump to send character
+E0ED 20 70 E1 p� JSR &E170 ; Wait for buffer to empty a bit
+E0F0 68 h PLA ; Get character back
+E0F1 A2 02 �. LDX #&02 ; X=2 for serial output buffer
+E0F3 20 F8 E1 �� JSR &E1F8 ; Send character to serial output buffer
+E0F6 28 ( PLP ; Restore IRQs
+
+E0F7 A9 10 �. LDA #&10 ; Check output destination
+E0F9 2C 7C 02 ,|. BIT &027C ; Is SPOOL output disabled?
+E0FC D0 0F �. BNE &E10D ; Yes, skip past SPOOL output
+E0FE AC 57 02 �W. LDY &0257 ; Get SPOOL handle
+E101 F0 0A �. BEQ &E10D ; If not open, skip past SPOOL output
+E103 68 h PLA ; Get character back
+E104 48 H PHA ; Resave character
+E105 38 8 SEC
+E106 66 EB f� ROR &EB ; Set RFS/CFS's 'spooling' flag
+E108 20 D4 FF �. JSR &FFD4 ; Write character to SPOOL channel
+E10B 46 EB F� LSR &EB ; Reset RFS/CFS's 'spooling' flag
+
+E10D 68 h PLA ; Restore all registers
+E10E 68 h PLA
+E10F A8 � TAY
+E110 68 h PLA
+E111 AA � TAX
+E112 68 h PLA
+E113 60 ` RTS ; Exit
+
+
+*************************************************************************
+* *
+* PRINTER DRIVER *
+* *
+*************************************************************************
+
+;A=character to print
+
+E114 BIT &027C ;if bit 6 of VDU byte =1 printer is disabled
+E117 BVS &E139 ;so E139
+
+E119 CMP &0286 ;compare with printer ignore character
+E11C BEQ &E139 ;if the same E139
+
+E11E PHP ;else save flags
+E11F SEI ;bar interrupts
+E120 TAX ;X=A
+E121 LDA #&04 ;A=4
+E123 BIT &027C ;read bit 2 'disable printer driver'
+E126 BNE &E138 ;if set printer is disabled so exit E138
+E128 TXA ;else A=X
+E129 LDX #&03 ;X=3
+E12B JSR &E1F8 ;and put character in printer buffer
+E12E BCS &E138 ;if carry set on return exit, buffer not full (empty?)
+
+E130 BIT &02D2 ;else check buffer busy flag if 0
+E133 BPL &E138 ;then E138 to exit
+E135 JSR &E13A ;else E13A to open printer cahnnel
+
+E138 PLP ;get back flags
+E139 RTS ;and exit
+
+E13A LDA &0285 ;check printer destination
+E13D BEQ &E1AD ;if 0 then E1AD clear printer buffer and exit
+E13F CMP #&01 ;if parallel printer not selected
+E141 BNE &E164 ;E164
+E143 JSR &E460 ;else read a byte from the printer buffer
+E146 ROR &02D2 ;if carry is set then 2d2 is -ve
+E149 BMI &E190 ;so return via E190
+E14B LDY #&82 ;else enable interrupt 1 of the external VIA
+E14D STY &FE6E ;
+E150 STA &FE61 ;pass code to centronics port
+E153 LDA &FE6C ;pulse CA2 line to generate STROBE signal
+E156 AND #&F1 ;to advise printer that
+E158 ORA #&0C ;valid data is
+E15A STA &FE6C ;waiting
+E15D ORA #&0E ;
+E15F STA &FE6C ;
+E162 BNE &E190 ;then exit
+
+*********:serial printer *********************************************
+
+E164 CMP #&02 ;is it Serial printer??
+E166 BNE &E191 ;if not E191
+E168 LDY &EA ;else is RS423 in use by cassette??
+E16A DEY ;
+E16B BPL &E1AD ;if so E1AD to flush buffer
+
+E16D LSR &02D2 ;else clear buffer busy flag
+E170 LSR &024F ;and RS423 busy flag
+E173 JSR &E741 ;count buffer if C is clear on return
+E176 BCC &E190 ;no room in buffer so exit
+E178 LDX #&20 ;else
+E17A LDY #&9F ;
+
+
+
+
+*************************************************************************
+* *
+* OSBYTE 156 update ACIA setting and RAM copy *
+* *
+*************************************************************************
+;on entry
+
+E17C PHP ;push flags
+E17D SEI ;bar interrupts
+E17E TYA ;A=Y
+E17F STX &FA ;&FA=X
+E181 AND &0250 ;A=old value AND Y EOR X
+E184 EOR &FA ;
+E186 LDX &0250 ;get old value in X
+E189 STA &0250 ;put new value in
+E18C STA &FE08 ;and store to ACIA control register
+E18F PLP ;get back flags
+E190 RTS ;and exit
+
+
+
+************ printer is neither serial or parallel so its user type *****
+
+E191 CLC ;clear carry
+E192 LDA #&01 ;A=1
+E194 JSR &E1A2 ;
+
+
+*************************************************************************
+* *
+* OSBYTE 123 Warn printer driver going dormant *
+* *
+*************************************************************************
+
+E197 ROR &02D2 ;mark printer buffer empty for osbyte
+E19A RTS ;and exit
+
+E19B BIT &02D2 ;if bit 7 is set buffer is empty
+E19E BMI &E19A ;so exit
+
+E1A0 LDA #&00 ;else A=0
+
+E1A2 LDX #&03 ;X=3
+E1A4 LDY &0285 ;Y=printer destination
+E1A7 JSR &E57E ;to JMP (NETV)
+E1AA JMP (&0222) ;jump to PRINT VECTOR for special routines
+
+
+*************** Buffer handling *****************************************
+ ;X=buffer number
+ ;Buffer number Address Flag Out pointer In pointer
+ ;0=Keyboard 3E0-3FF 2CF 2D8 2E1
+ ;1=RS423 Input A00-AFF 2D0 2D9 2E2
+ ;2=RS423 output 900-9BF 2D1 2DA 2E3
+ ;3=printer 880-8BF 2D2 2DB 2E4
+ ;4=sound0 840-84F 2D3 2DC 2E5
+ ;5=sound1 850-85F 2D4 2DD 2E6
+ ;6=sound2 860-86F 2D5 2DE 2E7
+ ;7=sound3 870-87F 2D6 2DF 2E8
+ ;8=speech 8C0-8FF 2D7 2E0 2E9
+
+
+E1AD CLC ;clear carry
+E1AE PHA ;save A
+E1AF PHP ;save flags
+E1B0 SEI ;set interrupts
+E1B1 BCS &E1BB ;if carry set on entry then E1BB
+E1B3 LDA &E9AD,X ;else get byte from baud rate/sound data table
+E1B6 BPL &E1BB ;if +ve the E1BB
+E1B8 JSR &ECA2 ;else clear sound data
+
+E1BB SEC ;set carry
+E1BC ROR &02CF,X ;rotate buffer flag to show buffer empty
+E1BF CPX #&02 ;if X>1 then its not an input buffer
+E1C1 BCS &E1CB ;so E1CB
+
+E1C3 LDA #&00 ;else Input buffer so A=0
+E1C5 STA &0268 ;store as length of key string
+E1C8 STA &026A ;and length of VDU queque
+E1CB JSR &E73B ;then enter via count purge vector any user routines
+E1CE PLP ;restore flags
+E1CF PLA ;restore A
+E1D0 RTS ;and exit
+
+
+
+*************************************************************************
+* *
+* COUNT PURGE VECTOR DEFAULT ENTRY *
+* *
+* *
+*************************************************************************
+;on entry if V set clear buffer
+; if C set get space left
+; else get bytes used
+
+E1D1 BVC &E1DA ;if bit 6 is set then E1DA
+E1D3 LDA &02D8,X ;else start of buffer=end of buffer
+E1D6 STA &02E1,X ;
+E1D9 RTS ;and exit
+
+E1DA PHP ;push flags
+E1DB SEI ;bar interrupts
+E1DC PHP ;push flags
+E1DD SEC ;set carry
+E1DE LDA &02E1,X ;get end of buffer
+E1E1 SBC &02D8,X ;subtract start of buffer
+E1E4 BCS &E1EA ;if carry caused E1EA
+E1E6 SEC ;set carry
+E1E7 SBC &E447,X ;subtract buffer start offset (i.e. add buffer length)
+E1EA PLP ;pull flags
+E1EB BCC &E1F3 ;if carry clear E1F3 to exit
+E1ED CLC ;clear carry
+E1EE ADC &E447,X ;adc to get bytes used
+E1F1 EOR #&FF ;and invert to get space left
+E1F3 LDY #&00 ;Y=0
+E1F5 TAX ;X=A
+E1F6 PLP ;get back flags
+E1F7 RTS ;and exit
+
+
+
+********** enter byte in buffer, wait and flash lights if full **********
+
+E1F8 SEI ;prevent interrupts
+E1F9 JSR &E4B0 ;entera byte in buffer X
+E1FC BCC &E20D ;if successful exit
+E1FE JSR &E9EA ;else switch on both keyboard lights
+E201 PHP ;push p
+E202 PHA ;push A
+E203 JSR &EEEB ;switch off unselected LEDs
+E206 PLA ;get back A
+E207 PLP ;and flags
+E208 BMI &E20D ;if return is -ve Escape pressed so exit
+E20A CLI ;else allow interrupts
+E20B BCS &E1F8 ;if byte didn't enter buffer go and try it again
+E20D RTS ;then return
+
+
diff --git a/docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/E20E b/docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/E20E
new file mode 100644
index 0000000..4f0b4b6
--- /dev/null
+++ b/docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/E20E
@@ -0,0 +1 @@
+OS SERIES VI
GEOFF COX
*************************************************************************
* *
* SAVE/LOAD ENTRY *
* *
* *
*************************************************************************
**************: clear osfile control block workspace ********************
E20E PHA ;push A
E20F LDA #&00 ;A=0
E211 STA &02EE,X ;clear osfile control block workspace
E214 STA &02EF,X ;
E217 STA &02F0,X ;
E21A STA &02F1,X ;
E21D PLA ;get back A
E21E RTS ;and exit
*********** shift through osfile control block **************************
E21F STY &E6 ;&E6=Y
E221 ROL ;A=A*2
E222 ROL ;*4
E223 ROL ;*8
E224 ROL ;*16
E225 LDY #&04 ;Y=4
E227 ROL ;A=A*32
E228 ROL &02EE,X ;shift bit 7 of A into shift register
E22B ROL &02EF,X ;and
E22E ROL &02F0,X ;shift
E231 ROL &02F1,X ;along
E234 BCS &E267 ;if carry set on exit then register has overflowed
;so bad address error
E236 DEY ;decrement Y
E237 BNE &E227 ;and if Y>0 then do another shift
E239 LDY &E6 ;get back original Y
E23B RTS ;and exit
*************************************************************************
* *
* *LOAD ENTRY *
* *
* *
*************************************************************************
E23C LDA #&FF ;signal that load is being performed
*************************************************************************
* *
* *SAVE ENTRY *
* *
* *
*************************************************************************
;on entry A=0 for save &ff for load
E23E STX &F2 ;store address of rest of command line
E240 STY &F3 ;
E242 STX &02EE ;x and Y are stored in OSfile control block
E245 STY &02EF ;
E248 PHA ;Push A
E249 LDX #&02 ;X=2
E24B JSR &E20E ;clear the shift register
E24E LDY #&FF ;Y=255
E250 STY &02F4 ;store im 2F4
E253 INY ;increment Y
E254 JSR &EA1D ;and call GSINIT to prepare for reading text line
E257 JSR &EA2F ;read a code from text line if OK read next
E25A BCC &E257 ;until end of line reached
E25C PLA ;get back A without stack changes
E25D PHA ;
E25E BEQ &E2C2 ;IF A=0 (SAVE) E2C2
E260 JSR &E2AD ;set up file block
E263 BCS &E2A0 ;if carry set do OSFILE
E265 BEQ &E2A5 ;else if A=0 goto OSFILE
E267 BRK ;
E268 DB &FC ;
E269 DB 'Bad Address' ;error
E274 BRK ;
*************************************************************************
* *
* OSBYTE 119 ENTRY *
* CLOSE SPOOL/ EXEC FILES *
* *
*************************************************************************
E275 LDX #&10 ;X=10 issue *SPOOL/EXEC files warning
E277 JSR &F168 ;and issue call
E27A BEQ &E29F ;if a rom accepts and issues a 0 then E29F to return
E27C JSR &F68B ;else close the current exec file
E27F LDA #&00 ;A=0
**************************************************************************
**************************************************************************
** **
** **
** *SPOOL **
** **
**************************************************************************
**************************************************************************
E281 PHP ;if A=0 file is closed so
E282 STY &E6 ;Store Y
E284 LDY &0257 ;get file handle
E287 STA &0257 ;store A as file handle
E28A BEQ &E28F ;if Y<>0 then E28F
E28C JSR OSFIND ;else close file via osfind
E28F LDY &E6 ;get back original Y
E291 PLP ;pull flags
E292 BEQ &E29F ;if A=0 on entry then exit
E294 LDA #&80 ;else A=&80
E296 JSR OSFIND ;to open file Y for output
E299 TAY ;Y=A
E29A BEQ &E310 ;and if this is =0 then E310 BAD COMMAND ERROR
E29C STA &0257 ;store file handle
E29F RTS ;and exit
E2A0 BNE &E310 ;if NE then BAD COMMAND error
E2A2 INC &02F4 ;increment 2F4 to 00
E2A5 LDX #&EE ;X=&EE
E2A7 LDY #&02 ;Y=&02
E2A9 PLA ;get back A
E2AA JMP OSFILE ;and JUMP to OSFILE
**** check for hex digit ************************************************
E2AD JSR &E03A ;look for NEWline
E2B0 JSR &E08F ;carry is set if it finds hex digit
E2B3 BCC &E2C1 ;so E2C1 exit
E2B5 JSR &E20E ;clear shift register
************** shift byte into control block ***************************
E2B8 JSR &E21F ;shift lower nybble of A into shift register
E2BB JSR &E08F ;then check for Hex digit
E2BE BCS &E2B8 ;if found then do it again
E2C0 SEC ;else set carry
E2C1 RTS ;and exit
**************; set up OSfile control block ****************************
E2C2 LDX #&0A ;X=0A
E2C4 JSR &E2AD ;
E2C7 BCC &E310 ;if no hex digit found EXIT via BAD Command error
E2C9 CLV ;clear bit 6
******************READ file length from text line************************
E2CA LDA (&F2),Y ;read next byte from text line
E2CC CMP #&2B ;is it '+'
E2CE BNE &E2D4 ;if not assume its a last byte address so e2d4
E2D0 BIT &D9B7 ;else set V and M flags
E2D3 INY ;increment Y to point to hex group
E2D4 LDX #&0E ;X=E
E2D6 JSR &E2AD ;
E2D9 BCC &E310 ;if carry clear no hex digit so exit via error
E2DB PHP ;save flags
E2DC BVC &E2ED ;if V set them E2ED explicit end address found
E2DE LDX #&FC ;else X=&FC
E2E0 CLC ;clear carry
E2E1 LDA &01FC,X ;and add length data to start address
E2E4 ADC &0200,X ;
E2E7 STA &0200,X ;
E2EA INX ;
E2EB BNE &E2E1 ;repeat until X=0
E2ED LDX #&03 ;X=3
E2EF LDA &02F8,X ;copy start adddress to load and execution addresses
E2F2 STA &02F4,X ;
E2F5 STA &02F0,X ;
E2F8 DEX ;
E2F9 BPL &E2EF ;
E2FB PLP ;get back flag
E2FC BEQ &E2A5 ;if end of command line reached then E2A5
; to do osfile
E2FE LDX #&06 ;else set up execution address
E300 JSR &E2AD ;
E303 BCC &E310 ;if error BAD COMMAND
E305 BEQ &E2A5 ;and if end of line reached do OSFILE
E307 LDX #&02 ;else set up load address
E309 JSR &E2AD ;
E30C BCC &E310 ;if error BAD command
E30E BEQ &E2A5 ;else on end of line do OSFILE
;anything else is an error!!!!
******** Bad command error ************************************
E310 BRK ;
E311 DB &FE ;error number
E312 DB 'Bad Command' ;
E31D BRK
E31E DB &FB ;
E31F DB 'Bad Key' ;
E326 BRK
*************************************************************************
* *
* *KEY ENTRY *
* *
*************************************************************************
E327 JSR &E04E ;set up key number in A
E32A BCC &E31D ;if not valid number give error
E32C CPX #&10 ;if key number greater than 15
E32E BCS &E31D ;if greater then give error
E330 JSR &E045 ;otherwise skip commas, and check for CR
E333 PHP ;save flags for later
E334 LDX &0B10 ;get pointer to top of existing key strings
E337 TYA ;save Y
E338 PHA ;to preserve text pointer
E339 JSR &E3D1 ;set up soft key definition
E33C PLA ;get back Y
E33D TAY ;
E33E PLP ;and flags
E33F BNE &E377 ;if CR found return else E377 to set up new string
E341 RTS ;else return to set null string
*************************************************************************
* *
* *FX OSBYTE *
* *
*************************************************************************
A=number
E342 JSR &E04E ;convert the number to binary
E345 BCC &E310 ;if bad number call bad command
E347 TXA ;save X
*************************************************************************
* *
* *CODE *MOTOR *OPT *ROM *TAPE *TV *
* *
*************************************************************************
;enter codes *CODE &88
*MOTOR &89
*OPT &8B
*TAPE &8C
*ROM &8D
*TV &90
E348 PHA ;save A
E349 LDA #&00 ;clear &E4/E5
E34B STA &E5 ;
E34D STA &E4 ;
E34F JSR &E043 ;skip commas and check for newline (CR)
E352 BEQ &E36C ;if CR found E36C
E354 JSR &E04E ;convert character to binary
E357 BCC &E310 ;if bad character bad command error
E359 STX &E5 ;else save it
E35B JSR &E045 ;skip comma and check CR
E35E BEQ &E36C ;if CR then E36C
E360 JSR &E04E ;get another parameter
E363 BCC &E310 ;if bad error
E365 STX &E4 ;else store in E4
E367 JSR &E03A ;now we must have a newline
E36A BNE &E310 ;if none then output an error
E36C LDY &E4 ;Y=third osbyte parameter
E36E LDX &E5 ;X=2nd
E370 PLA ;A=first
E371 JSR OSBYTE ;call osbyte
E374 BVS &E310 ;if V set on return then error
E376 RTS ;else RETURN
********* *KEY CONTINUED ************************************************
;X points to last byte of current key definitions
E377 SEC ;
E378 JSR &EA1E ;look for '"' on return bit 6 E4=1 bit 7=1 if '"'found
;this is a GSINIT call without initial CLC
E37B JSR &EA2F ;call GSREAD carry is set if end of line found
E37E BCS &E388 ;E388 to deal with end of line
E380 INX ;point to first byte of new key definition
E381 BEQ &E31D ;if X=0 buffer WILL overflow so exit with BAD KEY error
E383 STA &0B00,X ;store character
E386 BCC &E37B ;and loop to get next byte if end of line not found
E388 BNE &E31D ;if Z clear then no matching '"' found or for some
;other reason line doesn't terminate properly
E38A PHP ;else if all OK save flags
E38B SEI ;bar interrupts
E38C JSR &E3D1 ;and move string
E38F LDX #&10 ;set loop counter
E391 CPX &E6 ;if key being defined is found
E393 BEQ &E3A3 ;then skip rest of loop
E395 LDA &0B00,X ;else get start of string X
E398 CMP &0B00,Y ;compare with start of string Y
E39B BNE &E3A3 ;if not the same then skip rest of loop
E39D LDA &0B10 ;else store top of string definition
E3A0 STA &0B00,X ;in designated key pointer
E3A3 DEX ;decrement loop pointer X
E3A4 BPL &E391 ;and do it all again
E3A6 PLP ;get back flags
E3A7 RTS ;and exit
***********: set string lengths *****************************************
E3A8 PHP ;push flags
E3A9 SEI ;bar interrupts
E3AA LDA &0B10 ;get top of currently defined strings
E3AD SEC ;
E3AE SBC &0B00,Y ;subtract to get the number of bytes in strings
;above end of string Y
E3B1 STA &FB ;store this
E3B3 TXA ;save X
E3B4 PHA ;
E3B5 LDX #&10 ;and X=16
E3B7 LDA &0B00,X ;get start offset (from B00) of key string X
E3BA SEC ;
E3BB SBC &0B00,Y ;subtract offset of string we are working on
E3BE BCC &E3C8 ;if carry clear (B00+Y>B00+X) or
E3C0 BEQ &E3C8 ;result (in A)=0
E3C2 CMP &FB ;or greater or equal to number of bytes above
;string we are working on
E3C4 BCS &E3C8 ;then E3C8
E3C6 STA &FB ;else store A in &FB
E3C8 DEX ;point to next lower key offset
E3C9 BPL &E3B7 ;and if 0 or +ve go back and do it again
E3CB PLA ;else get back value of X
E3CC TAX ;
E3CD LDA &FB ;get back latest value of A
E3CF PLP ;pull flags
E3D0 RTS ;and return
***********: set up soft key definition *********************************
E3D1 PHP ;push P
E3D2 SEI ;bar interrupts
E3D3 TXA ;save X
E3D4 PHA ;push A
E3D5 LDY &E6 ;get key number
E3D7 JSR &E3A8 ;and set up &FB
E3DA LDA &0B00,Y ;get start of string
E3DD TAY ;put it in Y
E3DE CLC ;clear carry
E3DF ADC &FB ;add number of bytes above string
E3E1 TAX ;put this in X
E3E2 STA &FA ;and store it
E3E4 LDA &0268 ;check number of bytes left to remove from key buffer
;if not 0 key is being used (definition expanded so
;error. This stops *KEY 1 "*key1 FRED" etc.
E3E7 BEQ &E3F6 ;if not in use continue
E3E9 BRK ;
E3EA DB &FA ;error number
E3EB DB 'Key in use' ;
E3F5 BRK ;
E3F6 DEC &0284 ;decrement consistence flag to &FF to warn that key
;definitions are being changed
E3F9 PLA ;pull A
E3FA SEC ;
E3FB SBC &FA ;subtract &FA
E3FD STA &FA ;and re store it
E3FF BEQ &E40D ;if 0 then E40D
E401 LDA &0B01,X ;else move string
E404 STA &0B01,Y ;from X to Y
E407 INY ;
E408 INX ;
E409 DEC &FA ;for length of string
E40B BNE &E401 ;
E40D TYA ;store end of moved string(s)
E40E PHA ;
E40F LDY &E6 ;get back key number
E411 LDX #&10 ;point at top of last string
E413 LDA &0B00,X ;get this value
E416 CMP &0B00,Y ;compare it with start of new or re defined key
E419 BCC &E422 ;if less then E422
E41B BEQ &E422 ;if = then E422
E41D SBC &FB ;shift key definitions accordingly
E41F STA &0B00,X ;
E422 DEX ;point to next lowest string def
E423 BPL &E413 ;and if =>0 then loop and do it again
E425 LDA &0B10 ;else make top of key definitions
E428 STA &0B00,Y ;the start of our key def
E42B PLA ;get new end of strings
E42C STA &0B10 ;and store it
E42F TAX ;put A in X
E430 INC &0284 ;reset consistency flag
E433 PLP ;restore flags
E434 RTS ;and exit
\ No newline at end of file
diff --git a/docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/E435 b/docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/E435
new file mode 100644
index 0000000..636b244
--- /dev/null
+++ b/docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/E435
@@ -0,0 +1 @@
+**************** BUFFER ADDRESS HI LOOK UP TABLE ************************
E435 DB &03 ;keyboard
E436 DB &0A ;rs423 input
E437 DB &08 ;rs423 output
E438 DB &07 ;printer
E439 DB &07 ;sound 0
E43A DB &07 ;sound 1
E43B DB &07 ;sound 2
E43C DB &07 ;sound 3
E43D DB &09 ;speech
**************** BUFFER ADDRESS LO LOOK UP TABLE ************************
E43E DB &00
E43F DB &00
E440 DB &C0
E441 DB &C0
E442 DB &50
E443 DB &60
E444 DB &70
E445 DB &80
E446 DB &00
**************** BUFFER START ADDRESS OFFSET ****************************
E447 DB &E0
E448 DB &00
E449 DB &40
E44A DB &C0
E44B DB &F0
E44C DB &F0
E44D DB &F0
E44E DB &F0
E44F DB &C0
*******: get nominal buffer addresses in &FA/B **************************
; ON ENTRY X=buffer number
;Buffer number Address Flag Out pointer In pointer
;0=Keyboard 3E0-3FF 2CF 2D8 2E1
;1=RS423 Input A00-AFF 2D0 2D9 2E2
;2=RS423 output 900-9BF 2D1 2DA 2E3
;3=printer 880-8BF 2D2 2DB 2E4
;4=sound0 840-84F 2D3 2DC 2E5
;5=sound1 850-85F 2D4 2DD 2E6
;6=sound2 860-86F 2D5 2DE 2E7
;7=sound3 870-87F 2D6 2DF 2E8
;8=speech 8C0-8FF 2D7 2E0 2E9
E450 LDA &E43E,X ;get buffer base address lo
E453 STA &FA ;store it
E455 LDA &E435,X ;get buffer base address hi
E458 STA &FB ;store it
E45A RTS ;exit
*************************************************************************
* *
* OSBYTE 152 Examine Buffer status *
* *
*************************************************************************
;on entry X = buffer number
;on exit FA/B points to buffer start Y is offset to next character
;if buffer is empty C=1, Y is preserved else C=0
E45B BIT &D9B7 ;set V and
E45E BVS &E461 ;jump to E461
*************************************************************************
* *
* OSBYTE 145 Get byte from Buffer *
* *
*************************************************************************
;on entry X = buffer number
; ON EXIT Y is character extracted
;if buffer is empty C=1, else C=0
E460 CLV ;clear V
E461 JMP (&022C) ;Jump via REMV
*************************************************************************
* *
* REMV buffer remove vector default entry point *
* *
*************************************************************************
;on entry X = buffer number
;on exit if buffer is empty C=1, Y is preserved else C=0
E464 PHP ;push flags
E465 SEI ;bar interrupts
E466 LDA &02D8,X ;get output pointer for buffer X
E469 CMP &02E1,X ;compare to input pointer
E46C BEQ &E4E0 ;if equal buffer is empty so E4E0 to exit
E46E TAY ;else A=Y
E46F JSR &E450 ;and get buffer pointer into FA/B
E472 LDA (&FA),Y ;read byte from buffer
E474 BVS &E491 ;if V is set (on input) exit with CARRY clear
;Osbyte 152 has been done
E476 PHA ;else must be osbyte 145 so save byte
E477 INY ;increment Y
E478 TYA ;A=Y
E479 BNE &E47E ;if end of buffer not reached <>0 E47E
E47B LDA &E447,X ;get pointer start from offset table
E47E STA &02D8,X ;set buffer output pointer
E481 CPX #&02 ;if buffer is input (0 or 1)
E483 BCC &E48F ;then E48F
E485 CMP &02E1,X ;else for output buffers compare with buffer start
E488 BNE &E48F ;if not the same buffer is not empty so E48F
E48A LDY #&00 ;buffer is empty so Y=0
E48C JSR &E494 ;and enter EVENT routine to signal EVENT 0 buffer
;becoming empty
E48F PLA ;get back byte from buffer
E490 TAY ;put it in Y
E491 PLP ;get back flags
E492 CLC ;clear carry to indicate success
E493 RTS ;and exit
**************************************************************************
**************************************************************************
** **
** CAUSE AN EVENT **
** **
**************************************************************************
**************************************************************************
;on entry Y=event number
;A and X may be significant Y=A, A=event no. when event generated @E4A1
;on exit carry clear indicates action has been taken else carry set
E494 PHP ;push flags
E495 SEI ;bar interrupts
E496 PHA ;push A
E497 STA &FA ;&FA=A
E499 LDA &02BF,Y ;get enable event flag
E49C BEQ &E4DF ;if 0 event is not enabled so exit
E49E TYA ;else A=Y
E49F LDY &FA ;Y=A
E4A1 JSR &F0A5 ;vector through &220
E4A4 PLA ;get back A
E4A5 PLP ;get back flags
E4A6 CLC ;clear carry for success
E4A7 RTS ;and exit
********* check event 2 character entering buffer ***********************
E4A8 TYA ;A=Y
E4A9 LDY #&02 ;Y=2
E4AB JSR &E494 ;check event
E4AE TAY ;Y=A
*************************************************************************
* *
* OSBYTE 138 Put byte into Buffer *
* *
*************************************************************************
;on entry X is buffer number, Y is character to be written
E4AF TYA ;A=Y
E4B0 JMP (&022A) ;jump to INSBV
*************************************************************************
* *
* INSBV insert character in buffer vector default entry point *
* *
*************************************************************************
;on entry X is buffer number, A is character to be written
E4B3 PHP ;save flags
E4B4 SEI ;bar interrupts
E4B5 PHA ;save A
E4B6 LDY &02E1,X ;get buffer input pointer
E4B9 INY ;increment Y
E4BA BNE &E4BF ;if Y=0 then buffer is full else E4BF
E4BC LDY &E447,X ;get default buffer start
E4BF TYA ;put it in A
E4C0 CMP &02D8,X ;compare it with input pointer
E4C3 BEQ &E4D4 ;if equal buffer is full so E4D4
E4C5 LDY &02E1,X ;else get buffer end in Y
E4C8 STA &02E1,X ;and set it from A
E4CB JSR &E450 ;and point &FA/B at it
E4CE PLA ;get back byte
E4CF STA (&FA),Y ;store it in buffer
E4D1 PLP ;pull flags
E4D2 CLC ;clear carry for success
E4D3 RTS ;and exit
E4D4 PLA ;get back byte
E4D5 CPX #&02 ;if we are working on input buffer
E4D7 BCS &E4E0 ;then E4E0
E4D9 LDY #&01 ;else Y=1
E4DB JSR &E494 ;to service input buffer full event
E4DE PHA ;push A
***** return with carry set *********************************************
E4DF PLA ;restore A
E4E0 PLP ;restore flags
E4E1 SEC ;set carry
E4E2 RTS ;and exit
***************** CODE MODIFIER ROUTINE *********************************
* CHECK FOR ALPHA CHARACTER *
*************************************************************************
;ENTRY character in A
;exit with carry set if non-Alpha character
E4E3 PHA ;Save A
E4E4 AND #&DF ;convert lower to upper case
E4E6 CMP #&41 ;is it 'A' or greater ??
E4E8 BCC &E4EE ;if not exit routine with carry set
E4EA CMP #&5B ;is it less than 'Z'
E4EC BCC &E4EF ;if so exit with carry clear
E4EE SEC ;else clear carry
E4EF PLA ;get back original value of A
E4F0 RTS ;and Return
;
;
*******: INSERT byte in Keyboard buffer *********************************
E4F1 LDX #&00 ;X=0 to indicate keyboard buffer
*************************************************************************
* *
* OSBYTE 153 Put byte in input Buffer checking for ESCAPE *
* *
*************************************************************************
;on entry X = buffer number (either 0 or 1)
;X=1 is RS423 input
;X=0 is Keyboard
;Y is character to be written
E4F3 TXA ;A=buffer number
E4F4 AND &0245 ;and with RS423 mode (0 treat as keyboard
;1 ignore Escapes no events no soft keys)
E4F7 BNE &E4AF ;so if RS423 buffer AND RS423 in normal mode (1) E4AF
E4F9 TYA ;else Y=A character to write
E4FA EOR &026C ;compare with current escape ASCII code (0=match)
E4FD ORA &0275 ;or with current ESCAPE status (0=ESC, 1=ASCII)
E500 BNE &E4A8 ;if ASCII or no match E4A8 to enter byte in buffer
E502 LDA &0258 ;else get ESCAPE/BREAK action byte
E505 ROR ;Rotate to get ESCAPE bit into carry
E506 TYA ;get character back in A
E507 BCS &E513 ;and if escape disabled exit with carry clear
E509 LDY #&06 ;else signal EVENT 6 Escape pressed
E50B JSR &E494 ;
E50E BCC &E513 ;if event handles ESCAPE then exit with carry clear
E510 JSR &E674 ;else set ESCAPE flag
E513 CLC ;clear carry
E514 RTS ;and exit
******** get a byte from keyboard buffer and interpret as necessary *****
;on entry A=cursor editing status 1=return &87-&8B,
;2= use cursor keys as soft keys 11-15
;this area not reached if cursor editing is normal
E515 ROR ;get bit 1 into carry
E516 PLA ;get back A
E517 BCS &E592 ;if carry is set return
;else cursor keys are 'soft'
E519 TYA ;A=Y get back original key code (&80-&FF)
E51A PHA ;PUSH A
E51B LSR ;get high nybble into lo
E51C LSR ;
E51D LSR ;
E51E LSR ;A=8-&F
E51F EOR #&04 ;and invert bit 2
;&8 becomes &C
;&9 becomes &D
;&A becomes &E
;&B becomes &F
;&C becomes &8
;&D becomes &9
;&E becomes &A
;&F becomes &B
E521 TAY ;Y=A = 8-F
E522 LDA &0265,Y ;read 026D to 0274 code interpretation status
;0=ignore key, 1=expand as 'soft' key
;2-&FF add this to base for ASCII code
;note that provision is made for keypad operation
;as codes &C0-&FF cannot be generated from keyboard
;but are recognised by OS
;
E525 CMP #&01 ;is it 01
E527 BEQ &E594 ;if so expand as 'soft' key via E594
E529 PLA ;else get back original byte
E52A BCC &E539 ;if above CMP generated Carry then code 0 must have
;been returned so E539 to ignore
E52C AND #&0F ;else add ASCII to BASE key number so clear hi nybble
E52E CLC ;clear carry
E52F ADC &0265,Y ;add ASCII base
E532 CLC ;clear carry
E533 RTS ;and exit
;
*********** ERROR MADE IN USING EDIT FACILITY ***************************
E534 JSR &E86F ;produce bell
E537 PLA ;get back A, buffer number
E538 TAX ;X=buffer number
********get byte from buffer ********************************************
E539 JSR &E460 ;get byte from buffer X
E53C BCS &E593 ;if buffer empty E593 to exit
E53E PHA ;else Push byte
E53F CPX #&01 ;and if RS423 input buffer is not the one
E541 BNE &E549 ;then E549
E543 JSR &E173 ;else oswrch
E546 LDX #&01 ;X=1 (RS423 input buffer)
E548 SEC ;set carry
E549 PLA ;get back original byte
E54A BCC &E551 ;if carry clear (I.E not RS423 input) E551
E54C LDY &0245 ;else Y=RS423 mode (0 treat as keyboard )
E54F BNE &E592 ;if not 0 ignore escapes etc. goto E592
E551 TAY ;Y=A
E552 BPL &E592 ;if code is less that &80 its simple so E592
E554 AND #&0F ;else clear high nybble
E556 CMP #&0B ;if less than 11 then treat as special code
E558 BCC &E519 ;or function key and goto E519
E55A ADC #&7B ;else add &7C (&7B +C) to convert codes B-F to 7-B
E55C PHA ;Push A
E55D LDA &027D ;get cursor editing status
E560 BNE &E515 ;if not 0 (normal) E515
E562 LDA &027C ;else get character destination status
;Bit 0 enables RS423 driver
;BIT 1 disables VDU driver
;Bit 2 disables printer driver
;BIT 3 enables printer independent of CTRL B or CTRL C
;Bit 4 disables spooled output
;BIT 5 not used
;Bit 6 disables printer driver unless VDU 1 precedes character
;BIT 7 not used
E565 ROR ;get bit 1 into carry
E566 ROR ;
E567 PLA ;
E568 BCS &E539 ;if carry is set E539 screen disabled
E56A CMP #&87 ;else is it COPY key
E56C BEQ &E5A6 ;if so E5A6
E56E TAY ;else Y=A
E56F TXA ;A=X
E570 PHA ;Push X
E571 TYA ;get back Y
E572 JSR &D8CE ;execute edit action
E575 PLA ;restore X
E576 TAX ;
E577 BIT &025F ;check econet RDCH flag
E57A BPL &E581 ;if not set goto E581
E57C LDA #&06 ;else Econet function 6
E57E JMP (&0224) ;to the Econet vector
********* get byte from key string **************************************
;on entry 0268 contains key length
;and 02C9 key string pointer to next byte
E581 LDA &0268 ;get length of keystring
E584 BEQ &E539 ;if 0 E539 get a character from the buffer
E586 LDY &02C9 ;get soft key expansion pointer
E589 LDA &0B01,Y ;get character from string
E58C INC &02C9 ;increment pointer
E58F DEC &0268 ;decrement length
************** exit with carry clear ************************************
E592 CLC ;
E593 RTS ;exit
;
*** expand soft key strings *********************************************
Y=pointer to sring number
E594 PLA ;restore original code
E595 AND #&0F ;blank hi nybble to get key string number
E597 TAY ;Y=A
E598 JSR &E3A8 ;get string length in A
E59B STA &0268 ;and store it
E59E LDA &0B00,Y ;get start point
E5A1 STA &02C9 ;and store it
E5A4 BNE &E577 ;if not 0 then get byte via E577 and exit
*********** deal with COPY key ******************************************
E5A6 TXA ;A=X
E5A7 PHA ;Push A
E5A8 JSR &D905 ;read a character from the screen
E5AB TAY ;Y=A
E5AC BEQ &E534 ;if not valid A=0 so BEEP
E5AE PLA ;else restore X
E5AF TAX ;
E5B0 TYA ;and Y
E5B1 CLC ;clear carry
E5B2 RTS ;and exit
\ No newline at end of file
diff --git a/docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/E6B0 b/docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/E6B0
new file mode 100644
index 0000000..5f1e45f
--- /dev/null
+++ b/docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/E6B0
@@ -0,0 +1 @@
+*************************************************************************
* *
* OSBYTE LOOK UP TABLE
* *
*************************************************************************
E5B3 DB &21,&E8 ;OSBYTE 0 (&E821)
E5B5 DB &88,&E9 ;OSBYTE 1 (&E988)
E5B7 DB &D3,&E6 ;OSBYTE 2 (&E6D3)
E5B9 DB &97,&E9 ;OSBYTE 3 (&E997)
E5BB DB &97,&E9 ;OSBYTE 4 (&E997)
E5BD DB &76,&E9 ;OSBYTE 5 (&E976)
E5BF DB &88,&E9 ;OSBYTE 6 (&E988)
E5C1 DB &8B,&E6 ;OSBYTE 7 (&E68B)
E5C3 DB &89,&E6 ;OSBYTE 8 (&E689)
E5C5 DB &B0,&E6 ;OSBYTE 9 (&E6B0)
E5C7 DB &B2,&E6 ;OSBYTE 10 (&E6B2)
E5C9 DB &95,&E9 ;OSBYTE 11 (&E995)
E5CB DB &8C,&E9 ;OSBYTE 12 (&E98C)
E5CD DB &F9,&E6 ;OSBYTE 13 (&E6F9)
E5CF DB &FA,&E6 ;OSBYTE 14 (&E6FA)
E5D1 DB &A8,&F0 ;OSBYTE 15 (&F0A8)
E5D3 DB &06,&E7 ;OSBYTE 16 (&E706)
E5D5 DB &8C,&DE ;OSBYTE 17 (&DE8C)
E5D7 DB &C8,&E9 ;OSBYTE 18 (&E9C8)
E5D9 DB &B6,&E9 ;OSBYTE 19 (&E9B6)
E5DB DB &07,&CD ;OSBYTE 20 (&CD07)
E5DD DB &B4,&F0 ;OSBYTE 21 (&F0B4)
E5DF DB &6C,&E8 ;OSBYTE 117 (&E86C)
E5E1 DB &D9,&E9 ;OSBYTE 118 (&E9D9)
E5E3 DB &75,&E2 ;OSBYTE 119 (&E275)
E5E5 DB &45,&F0 ;OSBYTE 120 (&F045)
E5E7 DB &CF,&F0 ;OSBYTE 121 (&F0CF)
E5E9 DB &CD,&F0 ;OSBYTE 122 (&F0CD)
E5EB DB &97,&E1 ;OSBYTE 123 (&E197)
E5ED DB &73,&E6 ;OSBYTE 124 (&E673)
E5EF DB &74,&E6 ;OSBYTE 125 (&E674)
E5F1 DB &5C,&E6 ;OSBYTE 126 (&E65C)
E5F3 DB &35,&E0 ;OSBYTE 127 (&E035)
E5F5 DB &4F,&E7 ;OSBYTE 128 (&E74F)
E5F7 DB &13,&E7 ;OSBYTE 129 (&E713)
E5F9 DB &29,&E7 ;OSBYTE 130 (&E729)
E5FB DB &85,&F0 ;OSBYTE 131 (&F085)
E5FD DB &23,&D9 ;OSBYTE 132 (&D923)
E5FF DB &26,&D9 ;OSBYTE 133 (&D926)
E601 DB &47,&D6 ;OSBYTE 134 (&D647)
E603 DB &C2,&D7 ;OSBYTE 135 (&D7C2)
E605 DB &57,&E6 ;OSBYTE 136 (&E657)
E607 DB &7F,&E6 ;OSBYTE 137 (&E67F)
E609 DB &AF,&E4 ;OSBYTE 138 (&E4AF)
E60B DB &34,&E0 ;OSBYTE 139 (&E034)
E60D DB &35,&F1 ;OSBYTE 140 (&F135)
E60F DB &35,&F1 ;OSBYTE 141 (&F135)
E611 DB &E7,&DB ;OSBYTE 142 (&DBE7)
E613 DB &68,&F1 ;OSBYTE 143 (&F168)
E615 DB &E3,&EA ;OSBYTE 144 (&EAE3)
E617 DB &60,&E4 ;OSBYTE 145 (&E460)
E619 DB &AA,&FF ;OSBYTE 146 (&FFAA)
E61B DB &F4,&EA ;OSBYTE 147 (&EAF4)
E61D DB &AE,&FF ;OSBYTE 148 (&FFAE)
E61F DB &F9,&EA ;OSBYTE 149 (&EAF9)
E621 DB &B2,&FF ;OSBYTE 150 (&FFB2)
E623 DB &FE,&EA ;OSBYTE 151 (&EAFE)
E625 DB &5B,&E4 ;OSBYTE 152 (&E45B)
E627 DB &F3,&E4 ;OSBYTE 153 (&E4F3)
E629 DB &FF,&E9 ;OSBYTE 154 (&E9FF)
E62B DB &10,&EA ;OSBYTE 155 (&EA10)
E62D DB &7C,&E1 ;OSBYTE 156 (&E17C)
E62F DB &A7,&FF ;OSBYTE 157 (&FFA7)
E631 DB &6D,&EE ;OSBYTE 158 (&EE6D)
E633 DB &7F,&EE ;OSBYTE 159 (&EE7F)
E635 DB &C0,&E9 ;OSBYTE 160 (&E9C0)
E637 DB &9C,&E9 ;
E639 DB &59,&E6 ;
*************************************************************************
* *
* OSWORD LOOK UP TABLE *
* *
*************************************************************************
E63B DB &02,&E9 ;OSWORD 0 (&E902)
E63D DB &D5,&E8 ;OSWORD 1 (&E8D5)
E63F DB &E8,&E8 ;OSWORD 2 (&E8E8)
E641 DB &D1,&E8 ;OSWORD 3 (&E8D1)
E643 DB &E4,&E8 ;OSWORD 4 (&E8E4)
E645 DB &03,&E8 ;OSWORD 5 (&E803)
E647 DB &0B,&E8 ;OSWORD 6 (&E80B)
E649 DB &2D,&E8 ;OSWORD 7 (&E82D)
E64B DB &AE,&E8 ;OSWORD 8 (&E8AE)
E64D DB &35,&C7 ;OSWORD 9 (&C735)
E64F DB &F3,&CB ;OSWORD 10 (&CBF3)
E651 DB &48,&C7 ;OSWORD 11 (&C748)
E653 DB &E0,&C8 ;OSWORD 12 (&C8E0)
E655 DB &CE,&D5 ;OSWORD 13 (&D5CE)
*************************************************************************
* *
* OSBYTE 136 Execute Code via User Vector *
* *
* *CODE effectively *
* *
*************************************************************************
E658 LDA #00 ;A=0
*************************************************************************
* *
* *LINE entry *
* *
*************************************************************************
E659 JMP (&0200) ;Jump via USERV
*************************************************************************
* *
* OSBYTE 126 Acknowledge detection of ESCAPE condition *
* *
*************************************************************************
E65C LDX #&00 ;X=0
E65E BIT &FF ;if bit 7 not set there is no ESCAPE condition
E660 BPL &E673 ;so E673
E662 LDA &0276 ;else get ESCAPE Action, if this is 0
;Clear ESCAPE
;close EXEC files
;purge all buffers
;reset VDU paging counter
E665 BNE &E671 ;else do none of the above
E667 CLI ;allow interrupts
E668 STA &0269 ;number of lines printed since last halt in paged
;mode = 0
E66B JSR &F68D ;close any open EXEC files
E66E JSR &F0AA ;clear all buffers
E671 LDX #&FF ;X=&FF to indicate ESCAPE acknowledged
*************************************************************************
* *
* OSBYTE 124 Clear ESCAPE condition *
* *
*************************************************************************
E673 CLC ;clear carry
*************************************************************************
* *
* OSBYTE 125 Set ESCAPE flag *
* *
*************************************************************************
E674 ROR &FF ;clear bit 7 of ESCAPE flag
E676 BIT &027A ;read bit 7 of Tube flag
E679 BMI &E67C ;if set TUBE exists so E67C
E67B RTS ;else RETURN
;
E67C JMP &0403 ;Jump to Tube entry point
*************************************************************************
* *
* OSBYTE 137 Turn on Tape motor *
* *
*************************************************************************
E67F LDA &0282 ;get serial ULA control setting
E682 TAY ;Y=A
E683 ROL ;rotate left to get bit 7 into carry
E684 CPX #&01 ;if X=1 then user wants motor on so CARRY set else
;carry is cleared
E686 ROR ;put carry back in control RAM copy
E687 BVC &E6A7 ;if bit 6 is clear then cassette is selected
;so write to control register and RAM copy
E689 LDA #&38 ;A=ASCII 8
*************************************************************************
* *
* OSBYTE 08/07 set serial baud rates *
* *
*************************************************************************
on entry X=baud rate
A=8 transmit
A=7 receive
E68B EOR #&3F ;converts ASCII 8 to 7 binary and ASCII 7 to 8 binary
E68D STA &FA ;store result
E68F LDY &0282 ;get serial ULA control register setting
E692 CPX #&09 ;is it 9 or more?
E694 BCS &E6AD ;if so exit
E696 AND &E9AD,X ;and with byte from look up table
E699 STA &FB ;store it
E69B TYA ;put Y in A
E69C ORA &FA ;and or with Accumulator
E69E EOR &FA ;zero the three bits set true
E6A0 ORA &FB ;set up data read from look up table + bit 6
E6A2 ORA #&40 ;
E6A4 EOR &025D ;write cassette/RS423 flag
E6A7 STA &0282 ;store serial ULA flag
E6AA STA &FE10 ;and write to control register
E6AD TYA ;put Y in A to save old contents
E6AE TAX ;write new setting to X
E6AF RTS ;and return
OS SERIES VII
GEOFF COX
*************************************************************************
* *
* OSBYTE 9 Duration of first colour *
* *
*************************************************************************
;on entry Y=0, X=new value
E6B0 INY ;Y is incremented to 1
E6B1 CLC ;clear carry
*************************************************************************
* *
* OSBYTE 10 Duration of second colour *
* *
*************************************************************************
;on entry Y=0 or 1 if from FX 9 call, X=new value
E6B2 LDA &0252,Y ;get mark period count
E6B5 PHA ;push it
E6B6 TXA ;get new count
E6B7 STA &0252,Y ;store it
E6BA PLA ;get back original value
E6BB TAY ;put it in Y
E6BC LDA &0251 ;get value of flash counter
E6BF BNE &E6D1 ;if not zero E6D1
E6C1 STX &0251 ;else restore old value
E6C4 LDA &0248 ;get current video ULA control register setting
E6C7 PHP ;push flags
E6C8 ROR ;rotate bit 0 into carry, carry into bit 7
E6C9 PLP ;get back flags
E6CA ROL ;rotate back carry into bit 0
E6CB STA &0248 ;store it in RAM copy
E6CE STA &FE20 ;and ULA control register
E6D1 BVC &E6AD ;then exit via OSBYTE 7/8
*************************************************************************
* *
* OSBYTE 2 select input stream *
* *
*************************************************************************
;on input X contains stream number
E6D3 TXA ;A=X
E6D4 AND #&01 ;blank out bits 1 - 7
E6D6 PHA ;push A
E6D7 LDA &0250 ;and get current ACIA control setting
E6DA ROL ;Bit 7 into carry
E6DB CPX #&01 ;if X>=1 then
E6DD ROR ;bit 7 of A=1
E6DE CMP &0250 ;compare this with ACIA control setting
E6E1 PHP ;push processor
E6E2 STA &0250 ;put A into ACIA control setting
E6E5 STA &FE08 ;and write to control register
E6E8 JSR &E173 ;set up RS423 buffer
E6EB PLP ;get back P
E6EC BEQ &E6F1 ;if new setting different from old E6F1 else
E6EE BIT &FE09 ;set bit 6 and 7
E6F1 LDX &0241 ;get current input buffer number
E6F4 PLA ;get back A
E6F5 STA &0241 ;store it
E6F8 RTS ;and return
*************************************************************************
* *
* OSBYTE 13 disable events *
* *
*************************************************************************
;X contains event number 0-9
E6F9 TYA ;Y=0 A=0
*************************************************************************
* *
* OSBYTE 14 enable events *
* *
*************************************************************************
;X contains event number 0-9
E6FA CPX #&0A ;if X>9
E6FC BCS &E6AE ;goto E6AE for exit
E6FE LDY &02BF,X ;else get event enable flag
E701 STA &02BF,X ;store new value in flag
E704 BVC &E6AD ;and exit via E6AD
*************************************************************************
* *
* OSBYTE 16 Select A/D channel *
* *
*************************************************************************
;X contains channel number or 0 if disable conversion
E706 BEQ &E70B ;if X=0 then E70B
E708 JSR &DE8C ;start conversion
E70B LDA &024D ;get current maximum ADC channel number
E70E STX &024D ;store new value
E711 TAX ;put old value in X
E712 RTS ;and exit
;
*************************************************************************
* *
* OSBYTE 129 Read key within time limit *
* *
*************************************************************************
;X and Y contains either time limit in centi seconds Y=&7F max
; or Y=&FF and X=-ve INKEY value
E713 TYA ;A=Y
E714 BMI &E721 ;if Y=&FF the E721
E716 CLI ;else allow interrupts
E717 JSR &DEBB ;and go to timed routine
E71A BCS &E71F ;if carry set then E71F
E71C TAX ;then X=A
E71D LDA #&00 ;A=0
E71F TAY ;Y=A
E720 RTS ;and return
;
;scan keyboard
E721 TXA ;A=X
E722 EOR #&7F ;convert to keyboard input
E724 TAX ;X=A
E725 JSR &F068 ;then scan keyboard
E728 ROL ;put bit 7 into carry
E729 LDX #&FF ;X=&FF
E72B LDY #&FF ;Y=&FF
E72D BCS &E731 ;if bit 7 of A was set goto E731 (RTS)
E72F INX ;else X=0
E730 INY ;and Y=0
E731 RTS ;and exit
********** check occupancy of input or free space of output buffer *******
;X=buffer number
;Buffer number Address Flag Out pointer In pointer
;0=Keyboard 3E0-3FF 2CF 2D8 2E1
;1=RS423 Input A00-AFF 2D0 2D9 2E2
;2=RS423 output 900-9BF 2D1 2DA 2E3
;3=printer 880-8BF 2D2 2DB 2E4
;4=sound0 840-84F 2D3 2DC 2E5
;5=sound1 850-85F 2D4 2DD 2E6
;6=sound2 860-86F 2D5 2DE 2E7
;7=sound3 870-87F 2D6 2DF 2E8
;8=speech 8C0-8FF 2D7 2E0 2E9
E732 TXA ;buffer number in A
E733 EOR #&FF ;invert it
E735 TAX ;X=A
E736 CPX #&02 ;is X>1
E738 CLV ;clear V flag
E739 BVC &E73E ;and goto E73E count buffer
E73B BIT &D9B7 ;set V
E73E JMP (&022E) ;CNPV defaults to E1D1
************* check RS423 input buffer ************************************
E741 SEC
E742 LDX #&01 ;X=1 to point to buffer
E744 JSR &E738 ;and count it
E747 CPY #&01 ;if the hi byte of the answer is 1 or more
E749 BCS &E74E ;then Return
E74B CPX &025B ;else compare with minimum buffer space
E74E RTS ;and exit
*************************************************************************
* *
* OSBYTE 128 READ ADC CHANNEL *
* *
*************************************************************************
;ON Entry: X=0 Exit Y contains number of last channel converted
; X=channel number X,Y contain 16 bit value read from channe
; X<0 Y=&FF X returns information about various buffers
; X=&FF (keyboard ) X=number of characters in buffer
; X=&FE (RS423 Input) X=number of characters in buffer
; X=&FD (RS423 output) X=number of empty spaces in buffer
; X=&FC (Printer) X=number of empty spaces in buffer
; X=&FB (sound 0) X=number of empty spaces in buffer
; X=&FA (sound 1) X=number of empty spaces in buffer
; X=&F9 (sound 2) X=number of empty spaces in buffer
; X=&F8 (sound 3) X=number of empty spaces in buffer
; X=&F7 (Speech ) X=number of empty spaces in buffer
E74F BMI &E732 ;if X is -ve then E732 count spaces
E751 BEQ &E75F ;if X=0 then E75F
E753 CPX #&05 ;else check for Valid channel
E755 BCS &E729 ;if not E729 set X & Y to 0 and exit
E757 LDY &02B9,X ;get conversion values for channel of interest Hi &
E75A LDA &02B5,X ;lo byte
E75D TAX ;X=lo byte
E75E RTS ;and exit
E75F LDA &FE40 ;read system VIA port B
E762 ROR ;move high nybble to low
E763 ROR ;
E764 ROR ;
E765 ROR ;
E766 EOR #&FF ;and invert it
E768 AND #&03 ;isolate the FIRE buttons
E76A LDY &02BE ;get analogue system flag byte
E76D STX &02BE ;store X here
E770 TAX ;A=X bits 0 and 1 indicate fire buttons
E771 RTS ;and return
**************************************************************************
**************************************************************************
** **
** OSBYTE DEFAULT ENTRY POINT **
** **
** pointed to by default BYTEV **
** **
**************************************************************************
**************************************************************************
E772 PHA ;save A
E773 PHP ;save Processor flags
E774 SEI ;disable interrupts
E775 STA &EF ;store A,X,Y in zero page
E777 STX &F0 ;
E779 STY &F1 ;
E77B LDX #&07 ;X=7 to signal osbyte is being attempted
E77D CMP #&75 ;if A=0-116
E77F BCC &E7C2 ;then E7C2
E781 CMP #&A1 ;if A<161
E783 BCC &E78E ;then E78E
E785 CMP #&A6 ;if A=161-165
E787 BCC &E7C8 ;then EC78
E789 CLC ;clear carry
E78A LDA #&A1 ;A=&A1
E78C ADC #&00 ;
********* process osbyte calls 117 - 160 *****************************
E78E SEC ;set carry
E78F SBC #&5F ;convert to &16 to &41 (22-65)
E791 ASL ;double it (44-130)
E792 SEC ;set carry
E793 STY &F1 ;store Y
E795 TAY ;Y=A
E796 BIT &025E ;read econet intercept flag
E799 BPL &E7A2 ;if no econet intercept required E7A2
E79B TXA ;else A=X
E79C CLV ;V=0
E79D JSR &E57E ; to JMP via ECONET vector
E7A0 BVS &E7BC ;if return with V set E7BC
E7A2 LDA &E5B4,Y ;get address from table
E7A5 STA &FB ;store it as hi byte
E7A7 LDA &E5B3,Y ;repeat for lo byte
E7AA STA &FA ;
E7AC LDA &EF ;restore A
E7AE LDY &F1 ;Y
E7B0 BCS &E7B6 ;if carry is set E7B6
E7B2 LDY #&00 ;else
E7B4 LDA (&F0),Y ;get value from address pointed to by &F0/1 (Y,X)
E7B6 SEC ;set carry
E7B7 LDX &F0 ;restore X
E7B9 JSR &F058 ;call &FA/B
E7BC ROR ;C=bit 0
E7BD PLP ;get back flags
E7BE ROL ;bit 0=Carry
E7BF PLA ;get back A
E7C0 CLV ;clear V
E7C1 RTS ;and exit
*************** Process OSBYTE CALLS BELOW &75 **************************
E7C2 LDY #&00 ;Y=0
E7C4 CMP #&16 ;if A<&16
E7C6 BCC &E791 ;goto E791
E7C8 PHP ;push flags
E7C9 PHP ;push flags
E7CA PLA ;pull flags
E7CB PLA ;pull flags
E7CC JSR &F168 ;offer paged ROMS service 7/8 unrecognised osbyte/word
E7CF BNE &E7D6 ;if roms don't recognise it then E7D6
E7D1 LDX &F0 ;else restore X
E7D3 JMP &E7BC ;and exit
E7D6 PLP ;else pull flags
E7D7 PLA ;and A
E7D8 BIT &D9B7 ;set V and C
E7DB RTS ;and return
E7DC LDA &EB ;read cassette critical flag bit 7 = busy
E7DE BMI &E812 ;if busy then EB12
E7E0 LDA #&08 ;else A=8 to check current Catalogue status
E7E2 AND &E2 ;by anding with CFS status flag
E7E4 BNE &E7EA ;if not set (not in use) then E7EA RTS
E7E6 LDA #&88 ;A=%10001000
E7E8 AND &BB ;AND with FS options (short msg bits)
E7EA RTS ;RETURN
**************************************************************************
**************************************************************************
** **
** OSWORD DEFAULT ENTRY POINT **
** **
** pointed to by default WORDV **
** **
**************************************************************************
**************************************************************************
E7EB PHA ;Push A
E7EC PHP ;Push flags
E7ED SEI ;disable interrupts
E7EE STA &EF ;store A,X,Y
E7F0 STX &F0 ;
E7F2 STY &F1 ;
E7F4 LDX #&08 ;X=8
E7F6 CMP #&E0 ;if A=>224
E7F8 BCS &E78A ;then E78A with carry set
E7FA CMP #&0E ;else if A=>14
E7FC BCS &E7C8 ;else E7C8 with carry set pass to ROMS & exit
E7FE ADC #&44 ;add to form pointer to table
E800 ASL ;double it
E801 BCC &E793 ;goto E793 ALWAYS!! (carry clear E7F8)
;this reads bytes from table and enters routine
*************************************************************************
* *
* OSWORD 05 ENTRY POINT *
* *
* read a byte from I/O memory *
* *
*************************************************************************
;block of 4 bytes set at address pointed to by 00F0/1 (Y,X)
;XY +0 ADDRESS of byte
; +4 on exit byte read
E803 JSR &E815 ;set up address of data block
E806 LDA (&F9,X) ;get byte
E808 STA (&F0),Y ;store it
E80A RTS ;exit
*************************************************************************
* *
* OSWORD 06 ENTRY POINT *
* *
* write a byte to I/O memory *
* *
*************************************************************************
;block of 5 bytes set at address pointed to by 00F0/1 (Y,X)
;XY +0 ADDRESS of byte
; +4 byte to be written
E80B JSR &E815 ;set up address
E80E LDA (&F0),Y ;get byte
E810 STA (&F9,X) ;store it
E812 LDA #&00 ;a=0
E814 RTS ;exit
********************: set up data block *********************************
E815 STA &FA ;&FA=A
E817 INY ;Y=1
E818 LDA (&F0),Y ;get byte from block
E81A STA &FB ;store it
E81C LDY #&04 ;Y=4
E81E LDX #&01 ;X=1
E820 RTS ;and exit
*************************************************************************
* *
* OSBYTE 00 ENTRY POINT *
* *
* read OS version number *
* *
*************************************************************************
E821 BNE &E81E ;if A <> 0 then exit else print error
E823 BRK ;
E824 DB &F7 ;error number
E825 DB 'OS 1.20' ;error message
E82C BRK
\ No newline at end of file
diff --git a/docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/E887 b/docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/E887
new file mode 100644
index 0000000..cfdd00d
--- /dev/null
+++ b/docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/E887
@@ -0,0 +1 @@
+*************************************************************************
*************************************************************************
** **
** SOUND SYSTEM **
** **
*************************************************************************
*************************************************************************
-------------------------------------------------------------------------
| |
| OSWORD 07 - Make a sound |
| |
-------------------------------------------------------------------------
; On entry, control block pointed to by &F0/1
; Y=0 on entry
; XY +0 Channel - &hsfc for Hold, Sync, Flush, Channel
; 2 Amplitude/Envelope
; 4 Pitch
; 6 Duration
E82D INY
E82E LDA (&F0),Y ; Get channel high byte byte
E830 CMP #&FF
E832 BEQ &E88D ; Channel &FFxx, speech command
E834 CMP #&20 ; Is channel>=&20 ?
E836 LDX #&08 ; Prepare X=8 for unrecognised OSWORD call
E838 BCS &E7CA ; Pass to sideways ROMs for channel &2000+
E83A DEY ; Point back to channel low byte
E83B JSR &E8C9 ; Get Channel 0-3, and Cy if >=&10 for Flush
E83E ORA #&04 ; Convert to buffer number 4-7
E840 TAX
E841 BCC &E848 ; If no Flush, skip past
E843 JSR &E1AE ; Flush buffer
E846 LDY #&01 ; Point back to channel high byte
E848 JSR &E8C9 ; Get Sync 0-3, and Cy if >=&10 for Hold
E84B STA &FA ; Save Sync in &FA
E84D PHP ; Stack flags
E84E LDY #&06
E850 LDA (&F0),Y ; Get Duration byte
E852 PHA ; and stack it
E853 LDY #&04
E855 LDA (&F0),Y ; Get pitch byte
E857 PHA ; and stack it
E858 LDY #&02 ;
E85A LDA (&F0),Y ; Get amplitude/envelope byte
E85C ROL ; Move Hold into bit 0
E85D SEC ;set carry
E85E SBC #&02 ;subract 2
E860 ASL ;multiply by 4
E861 ASL ;
E862 ORA &FA ;add S byte (0-3)
; At this point,
; b7, 0=envelope, 1=volume
; b6-3, envelope-1 or volume+15
; b2, Hold
; b1-0, Sync
E864 JSR &E1F8 ; Insert into buffer
E867 BCC &E887 ; Buffer not full, jump to insert the rest
E869 PLA ; Drop stacked pitch
E86A PLA ; Drop stacked duration
E86B PLP ; Restore flags
; And exit
-------------------------------------------------------------------------
| |
| OSBYTE 117 - Read VDU status |
| |
-------------------------------------------------------------------------
E86C LDX &D0 ;get VDU status byte in X
E86E RTS ;and return
************* set up sound data for Bell ********************************
E86F PHP ;push P
E870 SEI ;bar interrupts
E871 LDA &0263 ;get bell channel number in A
E874 AND #&07 ; (bits 0-3 only set)
E876 ORA #&04 ;set bit 2
E878 TAX ;X=A = bell channel number +4=buffer number
E879 LDA &0264 ;get bell amplitude/envelope number
E87C JSR &E4B0 ;store it in buffer pointed to by X
E87F LDA &0266 ;get bell duration
E882 PHA ;save it
E883 LDA &0265 ;get bell frequency
E886 PHA ;save it
; Insert sound pitch and duration into sound buffer
;
E887 SEC ; Set carry
E888 ROR &0800,X ; Set bit 7 of channel flags to indicate it's active
E88B BMI &E8A4 ; Jump forward to insert pitch and duration
-------------------------------------------------------------------------
| |
| SOUND &FFxx - Speech System |
| |
-------------------------------------------------------------------------
; On entry, control block pointed to by &F0/1
; Y=1 on entry
; XY +0 Channel - &FFxx - xx=Speech command
; 2 Word number/Address
; 4 Ignored
; 6 Ignored
E88D PHP ; Save flags
E88E INY ; Y=2
E88F LDA (&F0),Y ; Get word number low byte
E891 PHA ; and stack it
E892 INY ; Y=3
E893 LDA (&F0),Y ; Get word number high byte
E895 PHA ; and stack it
E896 LDY #&00 ; Y=0
E898 LDA (&F0),Y ; Get speech command
E89A LDX #&08 ; X=8 for Speech buffer
E89C JSR &E1F8 ; Insert speech command into speech buffer
E89F BCS &E869 ; Buffer full, drop stack and abandon
E8A1 ROR &02D7 ; Clear bit 7 of speech buffer busy flag
; Insert two bytes into buffer
;
E8A4 PLA ; Get word number high byte or pitch back
E8A5 JSR &E4B0 ; Insert into speech buffer
E8A8 PLA ; Get word number low byte or duration back
E8A9 JSR &E4B0 ; Insert into speech buffer
E8AC PLP ; Restore flags
E8AD RTS ; and return
*************************************************************************
* *
* OSWORD 08 - Define Envelope *
* *
*************************************************************************
; On entry, control block pointed to by &F0/1
; Y=0 on entry
; A=envelope number from (&F0),0
;XY +0 Envelope number, also in A
; 1 bits 0-6 length of each step in centi-secsonds bit 7=0 auto repeat
; 2 change of Pitch per step (-128-+127) in section 1
; 3 change of Pitch per step (-128-+127) in section 2
; 4 change of Pitch per step (-128-+127) in section 3
; 5 number of steps in section 1 (0-255)
; 6 number of steps in section 2 (0-255)
; 7 number of steps in section 3 (0-255)
; 8 change of amplitude per step during attack phase (-127 to +127)
; 9 change of amplitude per step during decay phase (-127 to +127)
; 10 change of amplitude per step during sustain phase (-127 to +127)
; 11 change of amplitude per step during release phase (-127 to +127)
; 12 target level at end of attack phase (0-126)
; 13 target level at end of decay phase (0-126)
E8AE SBC #&01 ;set up appropriate displacement to storage area
E8B0 ASL ;A=(A-1)*16 or 15
E8B1 ASL ;
E8B2 ASL ;
E8B3 ASL ;
E8B4 ORA #&0F ;
E8B6 TAX ;X=A
E8B7 LDA #&00 ;A=0
E8B9 LDY #&10 ;Y=&10
E8BB CPY #&0E ;is Y>=14??
E8BD BCS &E8C1 ;yes then E8C1
E8BF LDA (&F0),Y ;else get byte from parameter block
E8C1 STA &08C0,X ;and store it in appropriate area
E8C4 DEX ;decrement X
E8C5 DEY ;Decrement Y
E8C6 BNE &E8BB ;if not 0 then do it again
E8C8 RTS ;else exit
;note that envelope number is NOT transferred
;
E8C9 LDA (&F0),Y ;get byte
E8CB CMP #&10 ;is it greater than 15, if so set carry
E8CD AND #&03 ;and 3 to clear bits 2-7
E8CF INY ;increment Y
E8D0 RTS ;and exit
*************************************************************************
* *
* OSWORD 03 ENTRY POINT *
* *
* read interval timer *
* *
*************************************************************************
F0/1 points to block to store data
E8D1 LDX #&0F ;X=&F displacement from clock to timer
E8D3 BNE &E8D8 ;jump to E8D8
*************************************************************************
* *
* OSWORD 01 ENTRY POINT *
* *
* read system clock *
* *
*************************************************************************
F0/1 points to block to store data
E8D5 LDX &0283 ;X=current system clock store pointer
E8D8 LDY #&04 ;Y=4
E8DA LDA &028D,X ;read byte
E8DD STA (&F0),Y ;store it in parameter block
E8DF INX ;X=x+1
E8E0 DEY ;Y=Y-1
E8E1 BPL &E8DA ;if Y>0 then do it again
E8E3 RTS ;else exit
*************************************************************************
* *
* OSWORD 04 ENTRY POINT *
* *
* write interval timer *
* *
*************************************************************************
F0/1 points to block to store data
E8E4 LDA #&0F ;offset between clock and timer
E8E6 BNE &E8EE ;jump to E8EE ALWAYS!!
*************************************************************************
* *
* OSWORD 02 ENTRY POINT *
* *
* write system clock *
* *
*************************************************************************
F0/1 points to block to store data
E8E8 LDA &0283 ;get current clock store pointer
E8EB EOR #&0F ;and invert to get inactive timer
E8ED CLC ;clear carry
E8EE PHA ;store A
E8EF TAX ;X=A
E8F0 LDY #&04 ;Y=4
E8F2 LDA (&F0),Y ;and transfer all 5 bytes
E8F4 STA &028D,X ;to the clock or timer
E8F7 INX ;
E8F8 DEY ;
E8F9 BPL &E8F2 ;if Y>0 then E8F2
E8FB PLA ;get back stack
E8FC BCS &E8E3 ;if set (write to timer) E8E3 exit
E8FE STA &0283 ;write back current clock store
E901 RTS ;and exit
*************************************************************************
* *
* OSWORD 00 ENTRY POINT *
* *
* read line from current input to memory *
* *
*************************************************************************
;F0/1 points to parameter block
; +0/1 buffer address for input
; +2 Maximum line length
; +3 minimum acceptable ASCII value
; +4 maximum acceptable ASCII value
E902 LDY #&04 ;Y=4
E904 LDA (&F0),Y ;transfer bytes 4,3,2 to 2B3-2B5
E906 STA &02B1,Y ;
E909 DEY ;decrement Y
E90A CPY #&02 ;until Y=1
E90C BCS &E904 ;
E90E LDA (&F0),Y ;get address of input buffer
E910 STA &E9 ;store it in &E9 as temporary buffer
E912 DEY ;decrement Y
E913 STY &0269 ;Y=0 store in print line counter for paged mode
E916 LDA (&F0),Y ;get lo byte of address
E918 STA &E8 ;and store in &E8
E91A CLI ;allow interrupts
E91B BCC &E924 ;Jump to E924
E91D LDA #&07 ;A=7
E91F DEY ;decrement Y
E920 INY ;increment Y
E921 JSR OSWRCH ;and call OSWRCH
E924 JSR OSRDCH ;else read character from input stream
E927 BCS &E972 ;if carry set then illegal character or other error
;exit via E972
E929 TAX ;X=A
E92A LDA &027C ;A=&27C get character destination status
E92D ROR ;put VDU driver bit in carry
E92E ROR ;if this is 1 VDU driver is disabled
E92F TXA ;X=A
E930 BCS &E937 ;if Carry set E937
E932 LDX &026A ;get number of items in VDU queque
E935 BNE &E921 ;if not 0 output character and loop round again
E937 CMP #&7F ;if character is not delete
E939 BNE &E942 ;goto E942
E93B CPY #&00 ;else is Y=0
E93D BEQ &E924 ;and goto E924
E93F DEY ;decrement Y
E940 BCS &E921 ;and if carry set E921 to output it
E942 CMP #&15 ;is it delete line &21
E944 BNE &E953 ;if not E953
E946 TYA ;else Y=A, if its 0 we are still reading first
;character
E947 BEQ &E924 ;so E924
E949 LDA #&7F ;else output DELETES
E94B JSR OSWRCH ;until Y=0
E94E DEY ;
E94F BNE &E94B ;
E951 BEQ &E924 ;then read character again
E953 STA (&E8),Y ;store character in designated buffer
E955 CMP #&0D ;is it CR?
E957 BEQ &E96C ;if so E96C
E959 CPY &02B3 ;else check the line length
E95C BCS &E91D ;if = or greater loop to ring bell
E95E CMP &02B4 ;check minimum character
E961 BCC &E91F ;if less than minimum backspace
E963 CMP &02B5 ;check maximum character
E966 BEQ &E920 ;if equal E920
E968 BCC &E920 ;or less E920
E96A BCS &E91F ;then JUMP E91F
E96C JSR OSNEWL ;output CR/LF
E96F JSR &E57E ;call Econet vector
E972 LDA &FF ;A=ESCAPE FLAG
E974 ROL ;put bit 7 into carry
E975 RTS ;and exit routine
*************************************************************************
* *
* OSBYTE 05 ENTRY POINT *
* *
* SELECT PRINTER TYPE *
* *
*************************************************************************
E976 CLI ;allow interrupts briefly
E977 SEI ;bar interrupts
E978 BIT &FF ;check if ESCAPE is pending
E97A BMI &E9AC ;if it is E9AC
E97C BIT &02D2 ;else check bit 7 buffer 3 (printer)
E97F BPL &E976 ;if not empty bit 7=0 E976
E981 JSR &E1A4 ;check for user defined routine
E984 LDY #&00 ;Y=0
E986 STY &F1 ;F1=0
*************************************************************************
* *
* OSBYTE 01 ENTRY POINT *
* *
* READ/WRITE USER FLAG (&281) *
* *
* AND *
* *
* OSBYTE 06 ENTRY POINT *
* *
* SET PRINTER IGNORE CHARACTER *
* *
*************************************************************************
; A contains osbyte number
E988 ORA #&F0 ;A=osbyte +&F0
E98A BNE &E99A ;JUMP to E99A
*************************************************************************
* *
* OSBYTE 0C ENTRY POINT *
* *
* SET KEYBOARD AUTOREPEAT RATE *
* *
*************************************************************************
E98C BNE &E995 ;if &F0<>0 goto E995
E98E LDX #&32 ;if X=0 in original call then X=32
E990 STX &0254 ;to set keyboard autorepeat delay ram copy
E993 LDX #&08 ;X=8
*************************************************************************
* *
* OSBYTE 0B ENTRY POINT *
* *
* SET KEYBOARD AUTOREPEAT DELAY *
* *
*************************************************************************
E995 ADC #&CF ;A=A+&D0 (carry set)
*************************************************************************
* *
* OSBYTE 03 ENTRY POINT *
* *
* SELECT OUTPUT STREAM *
* *
* AND *
* *
* *
* OSBYTE 04 ENTRY POINT *
* *
* ENABLE/DISABLE CURSOR EDITING *
* *
*************************************************************************
E997 CLC ;c,ear carry
E998 ADC #&E9 ;A=A+&E9
E99A STX &F0 ;store X
*************************************************************************
* *
* OSBYTE A6-FF ENTRY POINT *
* *
* READ/ WRITE SYSTEM VARIABLE OSBYTE NO. +&190 *
* *
*************************************************************************
E99C TAY ;Y=A
E99D LDA &0190,Y ;i.e. A=&190 +osbyte call!
E9A0 TAX ;preserve this
E9A1 AND &F1 ;new value = OLD value AND Y EOR X!
E9A3 EOR &F0 ;
E9A5 STA &0190,Y ;store it
E9A8 LDA &0191,Y ;get value of next byte into A
E9AB TAY ;Y=A
E9AC RTS ;and exit
******* SERIAL BAUD RATE LOOK UP TABLE ************************************
E9AD DB &64 ; % 01100100 75
E9AE DB &7F ; % 01111111 150
E9AF DB &5B ; % 01011011 300
E9B0 DB &6D ; % 01101101 1200
E9B1 DB &C9 ; % 11001001 2400
E9B2 DB &F6 ; % 11110110 4800
E9B3 DB &D2 ; % 11010010 9600
E9B4 DB &E4 ; % 11100100 19200
E9B5 DB &40 ; % 01000000
*************************************************************************
* *
* OSBYTE &13 ENTRY POINT *
* *
* Wait for VSync *
* *
*************************************************************************
E9B6 LDA &0240 ;read vertical sync counter
E9B9 CLI ;allow interrupts briefly
E9BA SEI ;bar interrupts
E9BB CMP &0240 ;has it changed?
E9BE BEQ &E9B9 ;no then E9B9
; falls through and reads VDU variable X
*************************************************************************
* *
* OSBYTE 160 ENTRY POINT *
* *
* READ VDU VARIABLE *
* *
*************************************************************************
;X contains the variable number
;0 =lefthand column in pixels current graphics window
;2 =Bottom row in pixels current graphics window
;4 =Right hand column in pixels current graphics window
;6 =Top row in pixels current graphics window
;8 =lefthand column in absolute characters current text window
;9 =Bottom row in absolute characters current text window
;10 =Right hand column in absolute characters current text window
;11 =Top row in absolute characters current text window
;12-15 current graphics origin in external coordinates
;16-19 current graphics cursor in external coordina4es
;20-23 old graphics cursor in internal coordinates
;24 current text cursor in X and Y
E9C0 LDY &0301,X ;get VDU variable hi
E9C3 LDA &0300,X ;low
E9C6 TAX ;X=low byte
E9C7 RTS ;and exit
*************************************************************************
* *
* OSBYTE 18 ENTRY POINT *
* *
* RESET SOFT KEYS *
* *
*************************************************************************
E9C8 LDA #&10 ;set consistency flag
E9CA STA &0284 ;
E9CD LDX #&00 ;X=0
E9CF STA &0B00,X ;and wipe clean
E9D2 INX ;soft key buffer
E9D3 BNE &E9CF ;until X=0 again
E9D5 STX &0284 ;zero consistency flag
E9D8 RTS ;and exit
*************************************************************************
* *
* OSBYTE &76 (118) SET LEDs to Keyboard Status *
* *
*************************************************************************
;osbyte entry with carry set
;called from &CB0E, &CAE3, &DB8B
E9D9 PHP ;PUSH P
E9DA SEI ;DISABLE INTERUPTS
E9DB LDA #&40 ;switch on CAPS and SHIFT lock lights
E9DD JSR &E9EA ;via subroutine
E9E0 BMI &E9E7 ;if ESCAPE exists (M set) E9E7
E9E2 CLC ;else clear V and C
E9E3 CLV ;before calling main keyboard routine to
E9E4 JSR &F068 ;switch on lights as required
E9E7 PLP ;get back flags
E9E8 ROL ;and rotate carry into bit 0
E9E9 RTS ;Return to calling routine
;
***************** Turn on keyboard lights and Test Escape flag ************
;called from &E1FE, &E9DD
;
E9EA BCC &E9F5 ;if carry clear
E9EC LDY #&07 ;switch on shift lock light
E9EE STY &FE40 ;
E9F1 DEY ;Y=6
E9F2 STY &FE40 ;switch on Caps lock light
E9F5 BIT &FF ;set minus flag if bit 7 of &00FF is set indicating
E9F7 RTS ;that ESCAPE condition exists, then return
;
****************** Write A to SYSTEM VIA register B *************************
;called from &CB6D, &CB73
E9F8 PHP ;push flags
E9F9 SEI ;disable interupts
E9FA STA &FE40 ;write register B from Accumulator
E9FD PLP ;get back flags
E9FE RTS ;and exit
;
*************************************************************************
* *
* OSBYTE 154 (&9A) SET VIDEO ULA *
* *
*************************************************************************
E9FF TXA ;osbyte entry! X transferred to A thence to
*******Set Video ULA control register **entry from VDU routines **************
;called from &CBA6, &DD37
EA00 PHP ;save flags
EA01 SEI ;disable interupts
EA02 STA &0248 ;save RAM copy of new parameter
EA05 STA &FE20 ;write to control register
EA08 LDA &0253 ;read space count
EA0B STA &0251 ;set flash counter to this value
EA0E PLP ;get back status
EA0F RTS ;and return
*************************************************************************
* *
* OSBYTE &9B (155) write to palette register *
* *
*************************************************************************
;entry X contains value to write
EA10 TXA ;A=X
EA11 EOR #&07 ;convert to palette format
EA13 PHP ;
EA14 SEI ;prevent interrupts
EA15 STA &0249 ;store as current palette setting
EA18 STA &FE21 ;store actual colour in register
EA1B PLP ;get back flags
EA1C RTS ;and exit
;
*************************************************************************
* GSINIT string initialisation *
* F2/3 points to string offset by Y *
* *
* ON EXIT *
* Z flag set indicates null string, *
* Y points to first non blank character *
* A contains first non blank character *
*************************************************************************
EA1D CLC ;clear carry
EA1E ROR &E4 ;Rotate moves carry to &E4
EA20 JSR &E03A ;get character from text
EA23 INY ;increment Y to point at next character
EA24 CMP #&22 ;check to see if its '"'
EA26 BEQ &EA2A ;if so EA2A (carry set)
EA28 DEY ;decrement Y
EA29 CLC ;clear carry
EA2A ROR &E4 ;move bit 7 to bit 6 and put carry in bit 7
EA2C CMP #&0D ;check to see if its CR to set Z
EA2E RTS ;and return
*************************************************************************
* GSREAD string read routine *
* F2/3 points to string offset by Y *
* *
*************************************************************************
;
EA2F LDA #&00 ;A=0
EA31 STA &E5 ;store A
EA33 LDA (&F2),Y ;read first character
EA35 CMP #&0D ;is it CR
EA37 BNE &EA3F ;if not goto EA3F
EA39 BIT &E4 ;if bit 7=1 no 2nd '"' found
EA3B BMI &EA8F ;goto EA8F
EA3D BPL &EA5A ;if not EA5A
EA3F CMP #&20 ;is less than a space?
EA41 BCC &EA8F ;goto EA8F
EA43 BNE &EA4B ;if its not a space EA4B
EA45 BIT &E4 ;is bit 7 of &E4 =1
EA47 BMI &EA89 ;if so goto EA89
EA49 BVC &EA5A ;if bit 6 = 0 EA5A
EA4B CMP #&22 ;is it '"'
EA4D BNE &EA5F ;if not EA5F
EA4F BIT &E4 ;if so and Bit 7 of &E4 =0 (no previous ")
EA51 BPL &EA89 ;then EA89
EA53 INY ;else point at next character
EA54 LDA (&F2),Y ;get it
EA56 CMP #&22 ;is it '"'
EA58 BEQ &EA89 ;if so then EA89
EA5A JSR &E03A ;read a byte from text
EA5D SEC ;and return with
EA5E RTS ;carry set
;
EA5F CMP #&7C ;is it '|'
EA61 BNE &EA89 ;if not EA89
EA63 INY ;if so increase Y to point to next character
EA64 LDA (&F2),Y ;get it
EA66 CMP #&7C ;and compare it with '|' again
EA68 BEQ &EA89 ;if its '|' then EA89
EA6A CMP #&22 ;else is it '"'
EA6C BEQ &EA89 ;if so then EA89
EA6E CMP #&21 ;is it !
EA70 BNE &EA77 ;if not then EA77
EA72 INY ;increment Y again
EA73 LDA #&80 ;set bit 7
EA75 BNE &EA31 ;loop back to EA31 to set bit 7 in next CHR
EA77 CMP #&20 ;is it a space
EA79 BCC &EA8F ;if less than EA8F Bad String Error
EA7B CMP #&3F ;is it '?'
EA7D BEQ &EA87 ;if so EA87
EA7F JSR &EABF ;else modify code as if CTRL had been pressed
EA82 BIT &D9B7 ;if bit 6 set
EA85 BVS &EA8A ;then EA8A
EA87 LDA #&7F ;else set bits 0 to 6 in A
EA89 CLV ;clear V
EA8A INY ;increment Y
EA8B ORA &E5 ;
EA8D CLC ;clear carry
EA8E RTS ;Return
;
EA8F BRK ;
EA90 DB &FD ;error number
EA93 DB 'Bad String' ; message
EA9B BRK ;
************ Modify code as if SHIFT pressed *****************************
EA9C CMP #&30 ;if A='0' skip routine
EA9E BEQ &EABE ;
EAA0 CMP #&40 ;if A='@' skip routine
EAA2 BEQ &EABE ;
EAA4 BCC &EAB8 ;if A<'@' then EAB8
EAA6 CMP #&7F ;else is it DELETE
EAA8 BEQ &EABE ;if so skip routine
EAAA BCS &EABC ;if greater than &7F then toggle bit 4
EAAC EOR #&30 ;reverse bits 4 and 5
EAAE CMP #&6F ;is it &6F (previously ' _' (&5F))
EAB0 BEQ &EAB6 ;goto EAB6
EAB2 CMP #&50 ;is it &50 (previously '`' (&60))
EAB4 BNE &EAB8 ;if not EAB8
EAB6 EOR #&1F ;else continue to convert ` _
EAB8 CMP #&21 ;compare &21 '!'
EABA BCC &EABE ;if less than return
EABC EOR #&10 ;else finish conversion by toggling bit 4
EABE RTS ;exit
;
;ASCII codes &00 &20 no change
;21-3F have bit 4 reverses (31-3F)
;41-5E A-Z have bit 5 reversed a-z
;5F & 60 are reversed
;61-7E bit 5 reversed a-z becomes A-Z
;DELETE unchanged
;&80+ has bit 4 changed
************** Implement CTRL codes *************************************
EABF CMP #&7F ;is it DEL
EAC1 BEQ &EAD1 ;if so ignore routine
EAC3 BCS &EAAC ;if greater than &7F go to EAAC
EAC5 CMP #&60 ;if A<>'`'
EAC7 BNE &EACB ;goto EACB
EAC9 LDA #&5F ;if A=&60, A=&5F
EACB CMP #&40 ;if A<&40
EACD BCC &EAD1 ;goto EAD1 and return unchanged
EACF AND #&1F ;else zero bits 5 to 7
EAD1 RTS ;return
;
EAD2 DB '/!BOOT',&0D
\ No newline at end of file
diff --git a/docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/EAD9 b/docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/EAD9
new file mode 100644
index 0000000..6682621
--- /dev/null
+++ b/docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/EAD9
@@ -0,0 +1 @@
+OS SERIES 8
GEOFF COX
*************************************************************************
* *
* OSBYTE &F7 (247) INTERCEPT BREAK *
* *
*************************************************************************
EAD9 LDA &0287 ;get BREAK vector code
EADC EOR #&4C ;produces 0 if JMP not in &287
EADE BNE &EAF3 ;if not goto EAF3
EAE0 JMP &0287 ;else jump to user BREAK code
*************************************************************************
* *
* OSBYTE &90 (144) *TV *
* *
*************************************************************************
;X=display delay
;Y=interlace flag
EAE3 LDA &0290 ;VDU vertical adjustment
EAE6 STX &0290 ;store new value
EAE9 TAX ;put old value in X
EAEA TYA ;put interlace flag in A
EAEB AND #&01 ;maximum value =1
EAED LDY &0291 ;get old value into Y
EAF0 STA &0291 ;put new value into A
EAF3 RTS ;and Exit
*************************************************************************
* *
* OSBYTE &93 (147) WRITE TO FRED *
* *
*************************************************************************
;X is offset within page
;Y is byte to write
EAF4 TYA ;
EAF5 STA &FC00,X ;
EAF8 RTS ;
*************************************************************************
* *
* OSBYTE &95 (149) WRITE TO JIM *
* *
*************************************************************************
;X is offset within page
;Y is byte to write
;
EAF9 TYA ;
EAFA STA &FD00,X ;
EAFD RTS ;
*************************************************************************
* *
* OSBYTE &97 (151) WRITE TO SHEILA *
* *
*************************************************************************
;X is offset within page
;Y is byte to write
EAFE TYA ;
EAFF STA &FE00,X ;
EB02 RTS ;
****************** Silence a sound channel *******************************
;X=channel number
EB03 LDA #&04 ;mark end of release phase
EB05 STA &0808,X ;to channel X
EB08 LDA #&C0 ;load code for zero volume
****** if sound not disabled set sound generator volume ******************
EB0A STA &0804,X ;store A to give basic sound level of Zero
EB0D LDY &0262 ;get sound output/enable flag
EB10 BEQ &EB14 ;if sound enabled goto EB14
EB12 LDA #&C0 ;else load zero sound code
EB14 SEC ;set carry
EB15 SBC #&40 ;subtract &40
EB17 LSR ;divide by 8
EB18 LSR ;to get into bits 0 - 3
EB19 LSR ;
EB1A EOR #&0F ;invert bits 0-3
EB1C ORA &EB3C,X ;get channel number into top nybble
EB1F ORA #&10 ;
EB21 PHP ;
EB22 SEI ;disable interrupts
EB23 LDY #&FF ;System VIA port A all outputs
EB25 STY &FE43 ;set
EB28 STA &FE4F ;output A on port A
EB2B INY ;Y=0
EB2C STY &FE40 ;enable sound chip
EB2F LDY #&02 ;set and
EB31 DEY ;execute short delay
EB32 BNE &EB31 ;
EB34 LDY #&08 ;then disable sound chip again
EB36 STY &FE40 ;
EB39 LDY #&04 ;set delay
EB3B DEY ;and loop delay
EB3C BNE &EB3B ;
EB3E PLP ;get back flags
EB3F RTS ;and exit
*******: Sound parameters look up table **********************************
EB40 DB &E0,&C0,&A0,&80
EB44 JMP &EC59 ;just to allow relative branches in early part
;of sound interrupt routine
*************************************************************************
* *
* PROCESS SOUND INTERRUPT *
* *
*************************************************************************
EB47 LDA #&00 ;
EB49 STA &083B ;zero number of channels on hold for sync
EB4C LDA &0838 ;get number of channels required for sync
EB4F BNE &EB57 ;if this <>0 then EB57
EB51 INC &083B ;else number of chanels on hold for sync =1
EB54 DEC &0838 ;number of channels required for sync =255
EB57 LDX #&08 ;set loop counter
EB59 DEX ;loop
EB5A LDA &0800,X ;get value of &800 +offset (sound queue occupancy)
EB5D BEQ &EB44 ;if 0 goto EC59 no sound this channel
EB5F LDA &02CF,X ;else get buffer busy flag
EB62 BMI &EB69 ;if negative (buffer empty) goto EB69
EB64 LDA &0818,X ;else if duration count not zer0
EB67 BNE &EB6C ;goto EB6C
EB69 JSR &EC6B ;check and pick up new sound if required
EB6C LDA &0818,X ;if duration count 0
EB6F BEQ &EB84 ;goto EB84
EB71 CMP #&FF ;else if it is &FF (infinite duration)
EB73 BEQ &EB87 ;go onto EB87
EB75 DEC &081C,X ;decrement 10 mS count
EB78 BNE &EB87 ;and if 0
EB7A LDA #&05 ;reset to 5
EB7C STA &081C,X ;to give 50 mSec delay
EB7F DEC &0818,X ;and decrement main counter
EB82 BNE &EB87 ;if not zero then EB87
EB84 JSR &EC6B ;else check and get nw sound
EB87 LDA &0824,X ;if step progress counter is 0 no envelope involved
EB8A BEQ &EB91 ;so jump to EB91
EB8C DEC &0824,X ;else decrement it
EB8F BNE &EB44 ;and if not zero go on to EC59
EB91 LDY &0820,X ;get envelope data offset from (8C0)
EB94 CPY #&FF ;if 255 no envelope set so
EB96 BEQ &EB44 ;goto EC59
EB98 LDA &08C0,Y ;else get get step length
EB9B AND #&7F ;zero repeat bit
EB9D STA &0824,X ;and store it
EBA0 LDA &0808,X ;get phase counter
EBA3 CMP #&04 ;if release phase completed
EBA5 BEQ &EC07 ;goto EC07
EBA7 LDA &0808,X ;else start new step by getting phase
EBAA CLC ;
EBAB ADC &0820,X ;add it to interval multiplier
EBAE TAY ;transfer to Y
EBAF LDA &08CB,Y ;and get target value base for envelope
EBB2 SEC ;
EBB3 SBC #&3F ;
EBB5 STA &083A ;store modified number as current target amplitude
EBB8 LDA &08C7,Y ;get byte from envelope store
EBBB STA &0839 ;store as current amplitude step
EBBE LDA &0804,X ;get base volumelevel
EBC1 PHA ;save it
EBC2 CLC ;clear carry
EBC3 ADC &0839 ;add to current amplitude step
EBC6 BVC &EBCF ;if no overflow
EBC8 ROL ;double it Carry = bit 7
EBC9 LDA #&3F ;if bit =1 A=&3F
EBCB BCS &EBCF ;into &EBCF
EBCD EOR #&FF ;else toggle bits (A=&C0)
;at this point the BASIC volume commands are converted
; &C0 (0) to &38 (-15) 3 times, In fact last 3 bits
;are ignored so &3F represents -15
EBCF STA &0804,X ;store in current volume
EBD2 ROL ;multiply by 2
EBD3 EOR &0804,X ;if bits 6 and 7 are equal
EBD6 BPL &EBE1 ;goto &EBE1
EBD8 LDA #&3F ;if carry clear A=&3F (maximum)
EBDA BCC &EBDE ;or
EBDC EOR #&FF ;&C0 minimum
EBDE STA &0804,X ;and this is stored in current volume
EBE1 DEC &0839 ;decrement amplitude change per step
EBE4 LDA &0804,X ;get volume again
EBE7 SEC ;set carry
EBE8 SBC &083A ;subtract target value
EBEB EOR &0839 ;negative value undicates correct trend
EBEE BMI &EBF9 ;so jump to next part
EBF0 LDA &083A ;else enter new phase
EBF3 STA &0804,X ;
EBF6 INC &0808,X ;
EBF9 PLA ;get the old volume level
EBFA EOR &0804,X ;and compare with the old
EBFD AND #&F8 ;
EBFF BEQ &EC07 ;if they are the same goto EC07
EC01 LDA &0804,X ;else set new level
EC04 JSR &EB0A ;via EB0A
EC07 LDA &0810,X ;get absolute pitch value
EC0A CMP #&03 ;if it =3
EC0C BEQ &EC59 ;skip rest of loop as all sections are finished
EC0E LDA &0814,X ;else if 814,X is not 0 current section is not
;complete
EC11 BNE &EC3D ;so EC3D
EC13 INC &0810,X ;else implement a section change
EC16 LDA &0810,X ;check if its complete
EC19 CMP #&03 ;if not
EC1B BNE &EC2D ;goto EC2D
EC1D LDY &0820,X ;else set A from
EC20 LDA &08C0,Y ;&820 and &8C0 (first envelope byte)
EC23 BMI &EC59 ;if negative there is no repeat
EC25 LDA #&00 ;else restart section sequence
EC27 STA &0830,X ;
EC2A STA &0810,X ;
EC2D LDA &0810,X ;get number of steps in new section
EC30 CLC ;
EC31 ADC &0820,X ;
EC34 TAY ;
EC35 LDA &08C4,Y ;
EC38 STA &0814,X ;set in 814+X
EC3B BEQ &EC59 ;and if 0 then EC59
EC3D DEC &0814,X ;decrement
EC40 LDA &0820,X ;and pick up rate of pitch change
EC43 CLC ;
EC44 ADC &0810,X ;
EC47 TAY ;
EC48 LDA &08C1,Y ;
EC4B CLC ;
EC4C ADC &0830,X ;add to rate of differential pitch change
EC4F STA &0830,X ;and save it
EC52 CLC ;
EC53 ADC &080C,X ;ad to base pitch
EC56 JSR &ED01 ;and set new pitch
EC59 CPX #&04 ;if X=4 (last channel)
EC5B BEQ &EC6A ;goto EC6A (RTS)
EC5D JMP &EB59 ;else do loop again
EC60 LDX #&08 ;X=7 again
EC62 DEX ;loop
EC63 JSR &ECA2 ;clear channel
EC66 CPX #&04 ;if not 4
EC68 BNE &EC62 ;do it again
EC6A RTS ;and return
;
EC6B LDA &0808,X ;check for last channel
EC6E CMP #&04 ;is it 4 (release complete)
EC70 BEQ &EC77 ;if so EC77
EC72 LDA #&03 ;else mark release in progress
EC74 STA &0808,X ;and store it
EC77 LDA &02CF,X ;is buffer not empty
EC7A BEQ &EC90 ;if so EC90
EC7C LDA #&00 ;else mark buffer not empty
EC7E STA &02CF,X ;an store it
EC81 LDY #&04 ;loop counter
EC83 STA &082B,Y ;zero sync bytes
EC86 DEY ;
EC87 BNE &EC83 ;until Y=0
EC89 STA &0818,X ;zero duration count
EC8C DEY ;and set sync count to
EC8D STY &0838 ;&FF
EC90 LDA &0828,X ;get synchronising flag
EC93 BEQ &ECDB ;if its 0 then ECDB
EC95 LDA &083B ;else get number of channels on hold
EC98 BEQ &ECD0 ;if 0 then ECD0
EC9A LDA #&00 ;else
EC9C STA &0828,X ;zero note length interval
EC9F JMP &ED98 ;and goto ED98
ECA2 JSR &EB03 ;silence the channel
ECA5 TYA ;Y=0 A=Y
ECA6 STA &0818,X ;zero main count
ECA9 STA &02CF,X ;mark buffer not empty
ECAC STA &0800,X ;mark channel dormant
ECAF LDY #&03 ;loop counter
ECB1 STA &082C,Y ;zero sync flags
ECB4 DEY ;
ECB5 BPL &ECB1 ;
ECB7 STY &0838 ;number of channels to &FF
ECBA BMI &ED06 ;jump to ED06 ALWAYS
ECBC PHP ;save flags
ECBD SEI ;and disable interrupts
ECBE LDA &0808,X ;check for end of release
ECC1 CMP #&04 ;
ECC3 BNE &ECCF ;and if not found ECCF
ECC5 JSR &E45B ;elseexamine buffer
ECC8 BCC &ECCF ;if not empty ECCF
ECCA LDA #&00 ;else mark channel dormant
ECCC STA &0800,X ;
ECCF PLP ;get back flags
ECD0 LDY &0820,X ;if no envelope 820=&FF
ECD3 CPY #&FF ;
ECD5 BNE &ECDA ;then terminate sound
ECD7 JSR &EB03 ;via EB03
ECDA RTS ;else return
;
************ Synchronise sound routines **********************************
ECDB JSR &E45B ;examine buffer if empty carry set
ECDE BCS &ECBC ;
ECE0 AND #&03 ;else examine next word if>3 or 0
ECE2 BEQ &EC9F ;goto ED98 (via EC9F)
ECE4 LDA &0838 ;else get synchronising count
ECE7 BEQ &ECFE ;in 0 (complete) goto ECFE
ECE9 INC &0828,X ;else set sync flag
ECEC BIT &0838 ;if 0838 is +ve S has already been set so
ECEF BPL &ECFB ;jump to ECFB
ECF1 JSR &E45B ;else get first byte
ECF4 AND #&03 ;mask bits 0,1
ECF6 STA &0838 ;and store result
ECF9 BPL &ECFE ;Jump to ECFE (ALWAYS!!)
ECFB DEC &0838 ;decrement 0838
ECFE JMP &ECD0 ;and silence the channel if envelope not in use
************ Pitch setting ***********************************************
ED01 CMP &082C,X ;If A=&82C,X then pitch is unchanged
ED04 BEQ &ECDA ;then exit via ECDA
ED06 STA &082C,X ;store new pitch
ED09 CPX #&04 ;if X<>4 then not noise so
ED0B BNE &ED16 ;jump to ED16
*********** Noise setting ************************************************
ED0D AND #&0F ;convert to chip format
ED0F ORA &EB3C,X ;
ED12 PHP ;save flags
ED13 JMP &ED95 ;and pass to chip control routine at EB22 via ED95
ED16 PHA ;
ED17 AND #&03 ;
ED19 STA &083C ;lose eigth tone surplus
ED1C LDA #&00 ;
ED1E STA &083D ;
ED21 PLA ;get back A
ED22 LSR ;divide by 12
ED23 LSR ;
ED24 CMP #&0C ;
ED26 BCC &ED2F ;
ED28 INC &083D ;store result
ED2B SBC #&0C ;with remainder in A
ED2D BNE &ED24 ;
;at this point 83D defines the Octave
;A the semitone within the octave
ED2F TAY ;Y=A
ED30 LDA &083D ;get octave number into A
ED33 PHA ;push it
ED34 LDA &EDFB,Y ;get byte from look up table
ED37 STA &083D ;store it
ED3A LDA &EE07,Y ;get byte from second table
ED3D PHA ;push it
ED3E AND #&03 ;keep two LS bits only
ED40 STA &083E ;save them
ED43 PLA ;pull second table byte
ED44 LSR ;push hi nybble into lo nybble
ED45 LSR ;
ED46 LSR ;
ED47 LSR ;
ED48 STA &083F ;store it
ED4B LDA &083D ;get back octave number
ED4E LDY &083C ;adjust for surplus eighth tones
ED51 BEQ &ED5F ;
ED53 SEC ;
ED54 SBC &083F ;
ED57 BCS &ED5C ;
ED59 DEC &083E ;
ED5C DEY ;
ED5D BNE &ED53 ;
ED5F STA &083D ;
ED62 PLA ;
ED63 TAY ;
ED64 BEQ &ED6F ;
ED66 LSR &083E ;
ED69 ROR &083D ;
ED6C DEY ;
ED6D BNE &ED66 ;
ED6F LDA &083D ;
ED72 CLC ;
ED73 ADC &C43D,X ;
ED76 STA &083D ;
ED79 BCC &ED7E ;
ED7B INC &083E ;
ED7E AND #&0F ;
ED80 ORA &EB3C,X ;
ED83 PHP ;push P
ED84 SEI ;bar interrupts
ED85 JSR &EB21 ;set up chip access 1
ED88 LDA &083D ;
ED8B LSR &083E ;
ED8E ROR ;
ED8F LSR &083E ;
ED92 ROR ;
ED93 LSR ;
ED94 LSR ;
ED95 JMP &EB22 ;set up chip access 2 and return
**************** Pick up and interpret sound buffer data *****************
ED98 PHP ;push flags
ED99 SEI ;disable interrupts
ED9A JSR &E460 ;read a byte from buffer
ED9D PHA ;push A
ED9E AND #&04 ;isolate H bit
EDA0 BEQ &EDB7 ;if 0 then EDB7
EDA2 PLA ;get back A
EDA3 LDY &0820,X ;if &820,X=&FF
EDA6 CPY #&FF ;envelope is not in use
EDA8 BNE &EDAD ;
EDAA JSR &EB03 ;so call EB03 to silence channel
EDAD JSR &E460 ;clear buffer of redundant data
EDB0 JSR &E460 ;and again
EDB3 PLP ;get back flags
EDB4 JMP &EDF7 ;set main duration count using last byte from buffer
EDB7 PLA ;get back A
EDB8 AND #&F8 ;zero bits 0-2
EDBA ASL ;put bit 7 into carry
EDBB BCC &EDC8 ;if zero (envelope) jump to EDC8
EDBD EOR #&FF ;invert A
EDBF LSR ;shift right
EDC0 SEC ;
EDC1 SBC #&40 ;subtract &40
EDC3 JSR &EB0A ;and set volume
EDC6 LDA #&FF ;A=&FF
EDC8 STA &0820,X ;get envelope no.-1 *16 into A
EDCB LDA #&05 ;set duration sub-counter
EDCD STA &081C,X ;
EDD0 LDA #&01 ;set phase counter
EDD2 STA &0824,X ;
EDD5 LDA #&00 ;set step counter
EDD7 STA &0814,X ;
EDDA STA &0808,X ;and envelope phase
EDDD STA &0830,X ;and pitch differential
EDE0 LDA #&FF ;
EDE2 STA &0810,X ;set step count
EDE5 JSR &E460 ;read pitch
EDE8 STA &080C,X ;set it
EDEB JSR &E460 ;read buffer
EDEE PLP ;
EDEF PHA ;save duration
EDF0 LDA &080C,X ;get back pitch value
EDF3 JSR &ED01 ;and set it
EDF6 PLA ;get back duration
EDF7 STA &0818,X ;set it
EDFA RTS ;and return
********************* Pitch look up table 1*****************************
EDFB DB &F0
EDFC DB &B7
EDFD DB &82
EDFE DB &4F
EDFF DB &20
EE00 DB &F3
EE01 DB &C8
EE02 DB &A0
EE03 DB &7B
EE04 DB &57
EE05 DB &35
EE06 DB &16
********************* Pitch look up table 2 *****************************
EE07 DB &E7
EE08 DB &D7
EE09 DB &CB
EE0A DB &C3
EE0B DB &B7
EE0C DB &AA
EE0D DB &A2
EE0E DB &9A
EE0F DB &92
EE10 DB &8A
EE11 DB &82
EE12 DB &7A
*********: set current filing system ROM/PHROM **************************
EE13 LDA #&EF ;get ROM
EE15 STA &F5 ;store it
EE17 RTS ;return
********** Get byte from data ROM ***************************************
EE18 LDX #&0D ;X=13
EE1A INC &F5 ;
EE1C LDY &F5 ;get Rom
EE1E BPL &EE59 ;if +ve it's a sideways ROM else it's a PHROM
EE20 LDX #&00 ;PHROM
EE22 STX &F7 ;set address pointer in PHROM
EE24 INX ;
EE25 STX &F6 ;to 0001
EE27 JSR &EEBB ;pass info to speech processor
EE2A LDX #&03 ;X=3
EE2C JSR &EE62 ;check for speech processor and output until
;it reports, read byte from ROM
EE2F CMP &DF0C,X ;if A<> DF0C+X then EE18 (DF0C = (C))
EE32 BNE &EE18 ;
EE34 DEX ;else decrement X
EE35 BPL &EE2C ;and do it again
EE37 LDA #&3E ;
EE39 STA &F6 ;get noe lo byte address
EE3B JSR &EEBB ;pass info to speech processor
EE3E LDX #&FF ;
EE40 JSR &EE62 ;check for speech proc. etc.
EE43 LDY #&08 ;
EE45 ASL ;
EE46 ROR &F7,X ;
EE48 DEY ;
EE49 BNE &EE45 ;
EE4B INX ;
EE4C BEQ &EE40 ;
EE4E CLC ;
EE4F BCC &EEBB ;
************ ROM SERVICE ************************************************
EE51 LDX #&0E ;
EE53 LDY &F5 ;if Y is negative (PHROM)
EE55 BMI &EE62 ;GOTO EE62
EE57 LDY #&FF ;else Y=255
EE59 PHP ;push flags
EE5A JSR &F168 ;offer paged rom service
EE5D PLP ;pull processor flags
EE5E CMP #&01 ;if A>0 set carry
EE60 TYA ;A=Y
EE61 RTS ;return
********* PHROM SERVICE *************************************************
;
EE62 PHP ;push processor flags
EE63 SEI ;disable interrupts
EE64 LDY #&10 ;Y=16
EE66 JSR &EE7F ;call EE7F (osbyte 159 write to speech processor
EE69 LDY #&00 ;Y=0
EE6B BEQ &EE84 ;Jump to EE84 (ALWAYS!!)
*************************************************************************
* *
* OSBYTE 158 read from speech processor *
* *
*************************************************************************
EE6D LDY #&00 ;Y=0 to set speech proc to read
EE6F BEQ &EE82 ;jump to EE82 always
;write A to speech processor as two nybbles
EE71 PHA ;push A
EE72 JSR &EE7A ;to write to speech processor
EE75 PLA ;get back A
EE76 ROR ;bring upper nybble to lower nybble
EE77 ROR ;by rotate right
EE78 ROR ;4 times
EE79 ROR ;
EE7A AND #&0F ;Y=lo nybble A +&40
EE7C ORA #&40 ;
EE7E TAY ;forming command for speech processor
*************************************************************************
* *
* OSBYTE 159 Write to speech processor *
* *
*************************************************************************
; on entry data or command in Y
EE7F TYA ;transfer command to A
EE80 LDY #&01 ;to set speech proc to write
;if Y=0 read speech processor
;if Y=1 write speech processor
EE82 PHP ;push flags
EE83 SEI ;disable interrupts
EE84 BIT &027B ;test for prescence of speech processor
EE87 BPL &EEAA ;if not there goto EEAA
EE89 PHA ;else push A
EE8A LDA &F075,Y ;
EE8D STA &FE43 ;set DDRA of system VIA to give 8 bit input (Y=0)
;or 8 bit output (Y=1)
EE90 PLA ;get back A
EE91 STA &FE4F ;and send to speech chip
EE94 LDA &F077,Y ;output Prt B of system VIA
EE97 STA &FE40 ;to select read or write (dependent on Y)
EE9A BIT &FE40 ;loop until
EE9D BMI &EE9A ;speech proceessor reports ready (bit 7 Prt B=0)
EE9F LDA &FE4F ;read speech processor data if input selected
EEA2 PHA ;push A
EEA3 LDA &F079,Y ;reset speech
EEA6 STA &FE40 ;processor
EEA9 PLA ;get back A
EEAA PLP ;get back flags
EEAB TAY ;transfer A to Y
EEAC RTS ;and exit routine
;
EEAD LDA &03CB ;set rom displacement pointer
EEB0 STA &F6 ;in &F6
EEB2 LDA &03CC ;
EEB5 STA &F7 ;And &F7
EEB7 LDA &F5 ;if F5 is +ve ROM is selected so
EEB9 BPL &EED9 ;goto EED9
EEBB PHP ;else push processor
EEBC SEI ;disable interrupts
EEBD LDA &F6 ;get lo displacement
EEBF JSR &EE71 ;pass two nyblles to speech proc.
EEC2 LDA &F5 ;&FA=&F5
EEC4 STA &FA ;
EEC6 LDA &F7 ;get hi displacement value
EEC8 ROL ;replace two most significant bits of A
EEC9 ROL ;by 2 LSBs of &FA
EECA LSR &FA ;
EECC ROR ;
EECD LSR &FA ;
EECF ROR ;
EED0 JSR &EE71 ;pass two nybbles to speech processor
EED3 LDA &FA ;FA has now been divided by 4 so pass
EED5 JSR &EE7A ;lower nybble to speech proc.
EED8 PLP ;get back flags
EED9 RTS ;and Return
;
\ No newline at end of file
diff --git a/docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/EEDA b/docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/EEDA
new file mode 100644
index 0000000..14e3c49
--- /dev/null
+++ b/docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/EEDA
@@ -0,0 +1 @@
+
************ Keyboard Input and housekeeping ************************
;entered from &F00C
EEDA LDX #&FF ;
EEDC LDA &EC ;get value of most recently pressed key
EEDE ORA &ED ;Or it with previous key to check for presses
EEE0 BNE &EEE8 ;if A=0 no keys pressed so off you go
EEE2 LDA #&81 ;else enable keybd interupt only by writing bit 7
EEE4 STA &FE4E ;and bit 0 of system VIA interupt register
EEE7 INX ;set X=0
EEE8 STX &0242 ;reset keyboard semaphore
**********: Turn on Keyboard indicators *******************************
EEEB PHP ;save flags
EEEC LDA &025A ;read keyboard status;
;Bit 7 =1 shift enabled
;Bit 6 =1 control pressed
;bit 5 =0 shift lock
;Bit 4 =0 Caps lock
;Bit 3 =1 shift pressed
EEEF LSR ;shift Caps bit into bit 3
EEF0 AND #&18 ;mask out all but 4 and 3
EEF2 ORA #&06 ;returns 6 if caps lock OFF &E if on
EEF4 STA &FE40 ;turn on or off caps light if required
EEF7 LSR ;bring shift bit into bit 3
EEF8 ORA #&07 ;
EEFA STA &FE40 ;turn on or off shift lock light
EEFD JSR &F12E ;set keyboard counter
EF00 PLA ;get back flags
EF01 RTS ;return
;
*************************************************************************
* *
* MAIN KEYBOARD HANDLING ROUTINE ENTRY FROM KEYV *
* ========================================================== *
* *
* ENTRY CONDITIONS *
* ================ *
* C=0, V=0 Test Shift and CTRL keys.. exit with N set if CTRL pressed *
* ........with V set if Shift pressed *
* *
* C=1, V=0 Scan Keyboard as OSBYTE &79 *
* *
* C=0, V=1 Key pressed interrupt entry *
* *
* C=1, V=1 Timer interrupt entry *
* *
*************************************************************************
EF02 BVC &EF0E ;if V is clear then leave interrupt routine
EF04 LDA #&01 ;disable keyboard interrupts
EF06 STA &FE4E ;by writing to VIA interrupt vector
EF09 BCS &EF13 ;if timer interrupt then EF13
EF0B JMP &F00F ;else to F00F
EF0E BCC &EF16 ;if test SHFT & CTRL goto EF16
EF10 JMP &F0D1 ;else to F0D1
;to scan keyboard
*************************************************************************
* Timer interrupt entry *
*************************************************************************
EF13 INC &0242 ;increment keyboard semaphore (to 0)
*************************************************************************
* Test Shift and Control Keys entry *
*************************************************************************
EF16 LDA &025A ;read keyboard status;
;Bit 7 =1 shift enabled
;Bit 6 =1 control pressed
;bit 5 =0 shift lock
;Bit 4 =0 Caps lock
;Bit 3 =1 shift pressed
EF19 AND #&B7 ;zero bits 3 and 6
EF1B LDX #&00 ;zero X to test for shift key press
EF1D JSR &F02A ;interrogate keyboard X=&80 if key determined by
;X on entry is pressed
EF20 STX &FA ;save X
EF22 CLV ;clear V
EF23 BPL &EF2A ;if no key press (X=0) then EF2A else
EF25 BIT &D9B7 ;set M and V
EF28 ORA #&08 ;set bit 3 to indicate Shift was pressed
EF2A INX ;check the control key
EF2B JSR &F02A ;via keyboard interrogate
EF2E BCC &EEEB ;if carry clear (entry via EF16) then off to EEEB
;to turn on keyboard lights as required
EF30 BPL &EF34 ;if key not pressed goto EF30
EF32 ORA #&40 ;or set CTRL pressed bit in keyboard status byte in A
EF34 STA &025A ;save status byte
EF37 LDX &EC ;if no key previously pressed
EF39 BEQ &EF4D ;then EF4D
EF3B JSR &F02A ;else check to see if key still pressed
EF3E BMI &EF50 ;if so enter repeat routine at EF50
EF40 CPX &EC ;else compare X with last key pressed (set flags)
EF42 STX &EC ;store X in last key pressed
EF44 BNE &EF4D ;if different from previous (Z clear) then EF4D
EF46 LDX #&00 ;else zero
EF48 STX &EC ;last key pressed
EF4A JSR &F01F ;and reset repeat system
EF4D JMP &EFE9 ;
********** REPEAT ACTION *************************************************
EF50 CPX &EC ;if X<>than last key pressed
EF52 BNE &EF42 ;then back to EF42
EF54 LDA &E7 ;else get value of AUTO REPEAT COUNTDOWN TIMER
EF56 BEQ &EF7B ;if 0 goto EF7B
EF58 DEC &E7 ;else decrement
EF5A BNE &EF7B ;and if not 0 goto EF7B
;this means that either the repeat system is dormant
;or it is not at the end of its count
EF5C LDA &02CA ;next value for countdown timer
EF5F STA &E7 ;store it
EF61 LDA &0255 ;get auto repeat rate from 0255
EF64 STA &02CA ;store it as next value for Countdown timer
EF67 LDA &025A ;get keyboard status
EF6A LDX &EC ;get last key pressed
EF6C CPX #&D0 ;if not SHIFT LOCK key (&D0) goto
EF6E BNE &EF7E ;EF7E
EF70 ORA #&90 ;sets shift enabled, & no caps lock all else preserved
EF72 EOR #&A0 ;reverses shift lock disables Caps lock and Shift enab
EF74 STA &025A ;reset keyboard status
EF77 LDA #&00 ;and set timer
EF79 STA &E7 ;to 0
EF7B JMP &EFE9 ;
EF7E CPX #&C0 ;if not CAPS LOCK
EF80 BNE &EF91 ;goto EF91
EF82 ORA #&A0 ;sets shift enabled and disables SHIFT LOCK
EF84 BIT &FA ;if bit 7 not set by (EF20) shift NOT pressed
EF86 BPL &EF8C ;goto EF8C
EF88 ORA #&10 ;else set CAPS LOCK not enabled
EF8A EOR #&80 ;reverse SHIFT enabled
EF8C EOR #&90 ;reverse both SHIFT enabled and CAPs Lock
EF8E JMP &EF74 ;reset keyboard status and set timer
*********** get ASCII code *********************************************
;on entry X=key pressed internal number
EF91 LDA &EFAB,X ;get code from look up table
EF94 BNE &EF99 ;if not zero goto EF99 else TAB pressed
EF96 LDA &026B ;get TAB character
EF99 LDX &025A ;get keyboard status
EF9C STX &FA ;store it in &FA
EF9E ROL &FA ;rotate to get CTRL pressed into bit 7
EFA0 BPL &EFA9 ;if CTRL NOT pressed EFA9
EFA2 LDX &ED ;get no. of previously pressed key
EFA4 BNE &EF4A ;if not 0 goto EF4A to reset repeat system etc.
EFA6 JSR &EABF ;else perform code changes for CTRL
EFA9 ROL &FA ;move shift lock into bit 7
EFAB BMI &EFB5 ;if not effective goto EFB5 else
EFAD JSR &EA9C ;make code changes for SHIFT
EFB0 ROL &FA ;move CAPS LOCK into bit 7
EFB2 JMP &EFC1 ;and Jump to EFC1
EFB5 ROL &FA ;move CAPS LOCK into bit 7
EFB7 BMI &EFC6 ;if not effective goto EFC6
EFB9 JSR &E4E3 ;else make changes for CAPS LOCK on, return with
;C clear for Alphabetic codes
EFBC BCS &EFC6 ;if carry set goto EFC6 else make changes for
EFBE JSR &EA9C ;SHIFT as above
EFC1 LDX &025A ;if shift enabled bit is clear
EFC4 BPL &EFD1 ;goto EFD1
EFC6 ROL &FA ;else get shift bit into 7
EFC8 BPL &EFD1 ;if not set goto EFD1
EFC8 BPL &EFD1 ;if not set goto EFD1
EFCA LDX &ED ;get previous key press
EFCC BNE &EFA4 ;if not 0 reset repeat system etc. via EFA4
EFCE JSR &EA9C ;else make code changes for SHIFT
EFD1 CMP &026C ;if A<> ESCAPE code
EFD4 BNE &EFDD ;goto EFDD
EFD6 LDX &0275 ;get Escape key status
EFD9 BNE &EFDD ;if ESCAPE returns ASCII code goto EFDD
EFDB STX &E7 ;store in Auto repeat countdown timer
EFDD TAY ;
EFDE JSR &F129 ;disable keyboard
EFE1 LDA &0259 ;read Keyboard disable flag used by Econet
EFE4 BNE &EFE9 ;if keyboard locked goto EFE9
EFE6 JSR &E4F1 ;put character in input buffer
EFE9 LDX &ED ;get previous keypress
EFEB BEQ &EFF8 ;if none EFF8
EFED JSR &F02A ;examine to see if key still pressed
EFF0 STX &ED ;store result
EFF2 BMI &EFF8 ;if pressed goto EFF8
EFF4 LDX #&00 ;else zero X
EFF6 STX &ED ;and &ED
EFF8 LDX &ED ;get &ED
EFFA BNE &F012 ;if not 0 goto F012
EFFC LDY #&EC ;get first keypress into Y
EFFE JSR &F0CC ;scan keyboard from &10 (osbyte 122)
F001 BMI &F00C ;if exit is negative goto F00C
F003 LDA &EC ;else make last key the
F005 STA &ED ;first key pressed i.e. rollover
F007 STX &EC ;save X into &EC
F009 JSR &F01F ;set keyboard repeat delay
F00C JMP &EEDA ;go back to EEDA
*************************************************************************
* Key pressed interrupt entry point *
*************************************************************************
;enters with X=key
F00F JSR &F02A ;check if key pressed
F012 LDA &EC ;get previous key press
F014 BNE &F00C ;if none back to housekeeping routine
F016 LDY #&ED ;get last keypress into Y
F018 JSR &F0CC ;and scan keyboard
F01B BMI &F00C ;if negative on exit back to housekeeping
F01D BPL &F007 ;else back to store X and reset keyboard delay etc.
**************** Set Autorepeat countdown timer **************************
F01F LDX #&01 ;set timer to 1
F021 STX &E7 ;
F023 LDX &0254 ;get next timer value
F026 STX &02CA ;and store it
F029 RTS ;
*************** Interrogate Keyboard routine ***********************
;
F02A LDY #&03 ;stop Auto scan
F02C STY &FE40 ;by writing to system VIA
F02F LDY #&7F ;set bits 0 to 6 of port A to input on bit 7
;output on bits 0 to 6
F031 STY &FE43 ;
F034 STX &FE4F ;write X to Port A system VIA
F037 LDX &FE4F ;read back &80 if key pressed (M set)
F03A RTS ;and return
*************************************************************************
* *
* KEY TRANSLATION TABLES *
* *
* 7 BLOCKS interspersed with unrelated code *
*************************************************************************
*key data block 1
F03B DB 71,33,34,35,84,38,87,2D,5E,8C
; q ,3 ,4 ,5 ,f4,8 ,f7,- ,^ ,rt
*************************************************************************
* *
* OSBYTE 120 Write KEY pressed Data *
* *
*************************************************************************
F045 STY &EC ;store Y as latest key pressed
F047 STX &ED ;store X as previous key pressed
F049 RTS ;and exit
*key data block 2
F04A DB 80,77,65,74,37,69,39,30,5F,8E
; f0,w ,e ,t ,7 ,i ,9 ,0 ,_ ,lft
F055 JMP (&FDFE) ;Jim paged entry vector
F058 JMP (&FA) ;
*key data block 3
F05A DB 31,32,64,72,36,75,6F,70,5B,8F
; 1 ,2 ,d ,r ,6 ,u ,o ,p ,[ ,dn
*************************************************************************
* *
* Main entry to keyboard routines *
* *
*************************************************************************
F065 BIT &D9B7 ;set V and M
F068 JMP (&0228) ;i.e. KEYV
*key data block 4
F06B DB 01,61,78,66,79,6A,6B,40,3A,0D
; CL,a ,x ,f ,y ,j ,k ,@ ,: ,RETN N.B CL=CAPS LOCK
*speech routine data
F075 DB 00,FF,01,02,09,0A
*key data block 5
F07B DB 02,73,63,67,68,6E,6C,3B,5D,7F
; SL,s ,c ,g ,h ,n ,l ,; ,] ,DEL N.B. SL=SHIFT LOCK
*************************************************************************
* *
* OSBYTE 131 READ OSHWM (PAGE in BASIC) *
* *
*************************************************************************
F085 LDY &0244 ;read current OSHWM
F088 LDX #&00 ;
F08A RTS ;
*key data block 6
F08B DB 00 ,7A,20 ,76,62,6D,2C,2E,2F,8B
; TAB,Z ,SPACE,V ,b ,m ,, ,. ,/ ,copy
***** set input buffer number and flush it *****************************
F095 LDX &0241 ;get current input buffer
F098 JMP &E1AD ;flush it
*key data block 7
F09B DB 1B,81,82,83,85,86,88,89,5C,8D
; ESC,f1,f2,f3,f5,f6,f8,f9,\ ,
F0A5 JMP (&0220) ;goto eventV handling routine
*************************************************************************
* *
* OSBYTE 15 FLUSH SELECTED BUFFER CLASS *
* *
*************************************************************************
;flush selected buffer
;X=0 flush all buffers
;X>1 flush input buffer
F0A8 BNE &F095 ;if X<>1 flush input buffer only
F0AA LDX #&08 ;else load highest buffer number (8)
F0AC CLI ;allow interrupts
F0AD SEI ;briefly!
F0AE JSR &F0B4 ;flush buffer
F0B1 DEX ;decrement X to point at next buffer
F0B2 BPL &F0AC ;if X>=0 flush next buffer
;at this point X=255
*************************************************************************
* *
* OSBYTE 21 FLUSH SPECIFIC BUFFER *
* *
*************************************************************************
;on entry X=buffer number
F0B4 CPX #&09 ;is X<9?
F0B6 BCC &F098 ;if so flush buffer or else
F0B8 RTS ;exit
;
*************************************************************************
* *
* Issue *HELP to ROMS *
* *
*************************************************************************
F0B9 LDX #&09 ;
F0BB JSR &F168 ;
F0BE JSR &FA4A ;print following message routine return after BRK
F0C1 DB &0D ;carriage return
F0C2 DS 'OS 1.20' ;help message
F0C9 DB &0D ;carriage return
F0CA BRK ;
F0CB RTS ;
*************************************************************************
* *
* OSBYTE 122 KEYBOARD SCAN FROM &10 (16) *
* *
*************************************************************************
;
F0CC CLC ;clear carry
F0CD LDX #&10 ;set X to 10
;
*************************************************************************
* *
* OSBYTE 121 KEYBOARD SCAN FROM VALUE IN X *
* *
*************************************************************************
F0CF BCS &F068 ;if carry set (by osbyte 121) F068
;Jmps via KEYV and hence back to;
*************************************************************************
* Scan Keyboard C=1, V=0 entry via KEYV *
*************************************************************************
F0D1 TXA ;if X is +ve goto F0D9
F0D2 BPL &F0D9 ;
F0D4 JSR &F02A ;else interrogate keyboard
F0D7 BCS &F12E ;if carry set F12E to set Auto scan else
F0D9 PHP ;push flags
F0DA BCC &F0DE ;if carry clear goto FODE else
F0DC LDY #&EE ;set Y so next operation saves to 2cd
F0DE STA &01DF,Y ;can be 2cb,2cc or 2cd
F0E1 LDX #&09 ;set X to 9
F0E3 JSR &F129 ;select auto scan
F0E6 LDA #&7F ;set port A for input on bit 7 others outputs
F0E8 STA &FE43 ;
F0EB LDA #&03 ;stop auto scan
F0ED STA &FE40 ;
F0F0 LDA #&0F ;select non-existent keyboard column F (0-9 only!)
F0F2 STA &FE4F ;
F0F5 LDA #&01 ;cancel keyboard interrupt
F0F7 STA &FE4D ;
F0FA STX &FE4F ;select column X (9 max)
F0FD BIT &FE4D ;if bit 1 =0 there is no keyboard interrupt so
F100 BEQ &F123 ;goto F123
F102 TXA ;else put column address in A
F103 CMP &01DF,Y ;compare with 1DF+Y
F106 BCC &F11E ;if less then F11E
F108 STA &FE4F ;else select column again
F10B BIT &FE4F ;and if bit 7 is 0
F10E BPL &F11E ;then F11E
F110 PLP ;else push and pull flags
F111 PHP ;
F112 BCS &F127 ;and if carry set goto F127
F114 PHA ;else Push A
F115 EOR &0000,Y ;EOR with EC,ED, or EE depending on Y value
F118 ASL ;shift left
F119 CMP #&01 ;set carry if = or greater than number holds EC,ED,EE
F11B PLA ;get back A
F11C BCS &F127 ;if carry set F127
F11E CLC ;else clear carry
F11F ADC #&10 ;add 16
F121 BPL &F103 ;and do it again if 0=<result<128
F123 DEX ;decrement X
F124 BPL &F0E3 ;scan again if greater than 0
F126 TXA ;
F127 TAX ;
F128 PLP ;pull flags
F129 JSR &F12E ;call autoscan
F12C CLI ;allow interrupts
F12D SEI ;disable interrupts
*************Enable counter scan of keyboard columns *******************
;called from &EEFD, &F129
F12E LDA #&0B ;select auto scan of keyboard
F130 STA &FE40 ;tell VIA
F133 TXA ;Get A into X
F134 RTS ;and return
\ No newline at end of file
diff --git a/docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/F135 b/docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/F135
new file mode 100644
index 0000000..11211c6
--- /dev/null
+++ b/docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/F135
@@ -0,0 +1,549 @@
+OS SERIES 9
+GEOFF COX
+*************************************************************************
+* *
+* OSBYTE 140 *TAPE *
+* selects TAPE filing system *
+* *
+* OSBYTE 141 *ROM *
+* selects ROM filing system *
+* *
+*************************************************************************
+
+F135 EOR #&8C ;if it's *TAPE A=0 *ROM A=1
+F137 ASL ;double it
+F138 STA &0247 ;store it in filing system flag store
+F13B CPX #&03 ;if X>=3 C set X=3 Z set
+F13D JMP &F14B ;
+
+******** set cassette options *******************************************
+ ;called after BREAK etc
+ ;lower nybble sets sequential access
+ ;upper sets load and save options
+
+ ;0000 Ignore errors, no messages
+ ;0001 Abort if error, no messages
+ ;0010 Retry after error, no messages
+ ;1000 Ignore error short messages
+ ;1001 Abort if error short messages
+ ;1010 Retry after error short messages
+ ;1100 Ignore error long messages
+ ;1101 Abort if error long messages
+ ;1110 Retry after error long messages
+
+
+F140 PHP ;save flags
+F141 LDA #&A1 ;set sequential access abort if error, no messages
+F143 STA &E3 ;set load/save retry if error, short messages
+F145 LDA #&19 ;set interblock gap
+F147 STA &03D1 ;and store it
+F14A PLP ;get back flags
+
+F14B PHP ;push flags
+F14C LDA #&06 ;get close files command to FSCV
+F14E JSR &E031 ;and gosub OSFSC
+F151 LDX #&06 ;
+F153 PLP ;get back flags
+F154 BEQ &F157 ;if Z set earlier
+F156 DEX ;do not decrement X
+F157 STX &C6 ;set current baud rate X=5 300 baud X=6 1200 baud
+
+********* reset FILEV,ARGSV,BGETV,BPUTV,GBPBV,FINDV,FSCV ******************
+********** to F27D, F18E, F4C9, F529, FFA6, F3CA, F1B1 ******************
+
+F159 LDX #&0E ;RESET VECTORS FOR FILE RELATED OPERATIONS
+F15B LDA &D951,X ;
+F15E STA &0211,X ;
+F161 DEX ;
+F162 BNE &F15B ;
+
+F164 STX &C2 ;&C2=0 PROGRESS FLAG
+F166 LDX #&0F ;set X to make Rom service call &F claim vectors!
+
+
+
+*************************************************************************
+* *
+* OSBYTE 143 *
+* Pass service commands to sideways ROMs *
+* *
+*************************************************************************
+ ; On entry X=service call number
+ ; Y=any additional parameter
+ ; On entry X=0 if claimed, or preserved if unclaimed
+ ; Y=any returned parameter
+ ; When called internally, EQ set if call claimed
+
+F168 LDA &F4 ; Get current ROM number
+F16A PHA ; Save it
+F16B TXA ; Pass service call number to A
+F16C LDX #&0F ; Start at ROM 15
+
+ ; Issue service call loop
+F16E INC &02A1,X ; Read bit 7 on ROM type table (no ROM has type 254 &FE)
+F171 DEC &02A1,X ;
+F174 BPL &F183 ; If not set (+ve result), step to next ROM down
+F176 STX &F4 ; Otherwise, select this ROM, &F4 RAM copy
+F178 STX &FE30 ; Page in selected ROM
+F17B JSR &8003 ; Call the ROM's service entry
+ ; X and P do not need to be preserved by the ROM
+F17E TAX ; On exit pass A to X to chech if claimed
+F17F BEQ &F186 ; If 0, service call claimed, reselect ROM and exit
+F181 LDX &F4 ; Otherwise, get current ROM back
+F183 DEX ; Step to next ROM down
+F184 BPL &F16E ; Loop until done ROM 0
+
+F186 PLA ; Get back original ROM number
+F187 STA &F4 ; Set ROM number RAM copy
+F189 STA &FE30 ; Page in the original ROM
+F18C TXA ; Pass X back to A to set zero flag
+F18D RTS ; And return
+
+
+
+*************************************************************************
+* *
+* CFS OSARGS entry point *
+*
+*************************************************************************
+
+F18E ORA #&00 ;is A=00
+F190 BNE &F1A2 ;if not return
+F192 CPY #&00 ;is Y=0
+F194 BNE &F1A2 ;if not return
+F196 LDA &C6 ;else get current baud rate and zero bit 2
+F198 AND #&FB ;C6=5 becomes 1, 6 becomes 2
+F19A ORA &0247 ;if cassette selected A=0 else A=2
+F19D ASL ;multiply by 2
+F19E ORA &0247 ;Or it again
+F1A1 LSR ;divide by 2
+F1A2 RTS ;return cassette =0
+
+*************************************************************************
+* *
+* FSC VECTOR TABLE *
+* *
+*************************************************************************
+
+F1A3 DB 4C,F5 ; *OPT (F54C)
+F1A5 DB 1D,F6 ; check EOF (F61D)
+F1A7 DB 04,F3 ; */ (F304)
+F1A9 DB 0F,E3 ; unknown command (E30F)
+F1AB DB 04,F3 ; *RUN (F304)
+F1AD DB 2A,F3 ; *CAT (F32A)
+F1AF DB 74,E2 ; osbyte 77 (E274)
+
+
+*************************************************************************
+* Filing System control entry OSFSC *
+* Entry via 021E FSCV *
+* A= index 0 to 7 *
+*************************************************************************
+ ;on entry A is reason code
+ ;A=0 A *OPT command has been used X & Y are the 2 parameters
+ ;A=1 EOF is being checked, on entry X=File handle
+ on Exit X=FF = EOF exists else 00
+ ;A=2 A */ command has been used *RUN the file
+ ;A=3 An unrecognised OS command has ben used X,Y point at command
+ ;A=4 A *RUN command has been used X,Y point at filename
+ ;A=5 A *CAT cammand has been issued X,Y point to rest of command
+ ;A=6 New filing system about to take over, close SPOOL & EXEC files
+ ;A=7 Return in X and Y lowest and highest file handle used
+ ;A=8 OS about to process *command
+
+F1B1 CMP #&07 ;if A>6
+F1B3 BCS &F1A2 ;goto F1A2 (RTS)
+F1B5 STX &BC ;else save X
+F1B7 ASL ;A=A*2
+F1B8 TAX ;X=A to get offset
+F1B9 LDA &F1A4,X ;get hi byte of address
+F1BC PHA ;push it
+F1BD LDA &F1A3,X ;get lo byte of address
+F1C0 PHA ;push it
+F1C1 LDX &BC ;get back X
+F1C3 RTS ;this now jumps to the address got from the table +1
+ ;the next RTS takes us back to CLI
+
+
+
+*************************************************************************
+* *
+* LOAD FILE *
+* *
+*************************************************************************
+
+F1C4 PHP ;save flags on stack
+F1C5 PHA ;save A on stack
+F1C6 JSR &FB27 ;Set cassette optionsinto (BB),set C7=6
+ ;claim serial system for cassette
+F1C9 LDA &03C2 ;execution address LO
+F1CC PHA ;save A on stack
+F1CD JSR &F631 ;search for file
+F1D0 PLA ;get back A
+F1D1 BEQ &F1ED ;if A=0 F1ED
+F1D3 LDX #&03 ;else X=3
+F1D5 LDA #&FF ;A=&FF
+F1D7 PHA ;save A on stack
+F1D8 LDA &03BE,X ;get load address
+F1DB STA &B0,X ;store it as current load address
+F1DD PLA ;get back A
+F1DE AND &B0,X ;
+F1E0 DEX ;X=X-1
+F1E1 BPL &F1D7 ;until all 4 bytes copied
+
+F1E3 CMP #&FF ;if all bytes contain don't contain &FF
+F1E5 BNE &F1ED ;continue
+F1E7 JSR &FAE8 ;else sound bell, reset ACIA & motor off
+F1EA JMP &E267 ;'Bad Address' error
+
+F1ED LDA &03CA ;block flag
+F1F0 LSR ;set carry from bit 0
+F1F1 PLA ;get back A
+F1F2 BEQ &F202 ;if A=0 F202
+F1F4 BCC &F209 ;if carry clear F209
+
+
+*************** LOCKED FILE ROUTINE *************************************
+
+F1F6 JSR &FAF2 ;enable second processor and reset serial system
+
+F1F9 BRK ;
+F1FA DB &E5 ;error number
+F1FC 'Locked' ;
+F201 BRK ;
+
+
+F202 BCC &F209 ;if carry clear F209
+F204 LDA #&03 ;else A=3
+F206 STA &0258 ;store to cause ESCAPE disable and memory
+ ;clear on break
+
+F209 LDA #&30 ;
+F20B AND &BB ;current OPTions
+F20D BEQ &F213 ;if options and #&30 =0 ignore error condition is set
+F20F LDA &C1 ;else get checksum result
+F211 BNE &F21D ;and if not 0 F21D
+
+F213 TYA ;A=Y
+F214 PHA ;save A on stack
+F215 JSR &FBBB ;read from second processor if present
+F218 PLA ;get back A
+F219 TAY ;Y=A
+F21A JSR &F7D5 ;reset flags and check block length
+F21D JSR &F9B4 ;load file from tape
+F220 BNE &F255 ;if not found return to search
+F222 JSR &FB69 ;increment current block number
+F225 BIT &03CA ;block flag
+F228 BMI &F232 ;if bit 7=1 then this is last block so F232
+F22A JSR &F96A ;else increment current load address
+F22D JSR &F77B ;read block header
+F230 BNE &F209 ;and goto F209
+
+******** store data in OSFILE parameter block ***************************
+
+F232 LDY #&0A ;Y=&0A
+F234 LDA &CC ;file length counter lo
+F236 STA (&C8),Y ;OSFILE parameter block
+F238 INY ;Y=Y+1
+F239 LDA &CD ;file length counter hi
+F23B STA (&C8),Y ;OSFILE parameter block
+F23D LDA #&00 ;A=0
+F23F INY ;Y=Y+1
+F240 STA (&C8),Y ;OSFILE parameter block
+F242 INY ;Y=Y+1
+F243 STA (&C8),Y ;OSFILE parameter block
+F245 PLP ;get back flags
+F246 JSR &FAE8 ;bell, reset ACIA & motor
+F249 BIT &BA ;current block flag
+F24B BMI &F254 ;return
+F24D PHP ;save flags on stack
+F24E JSR &FA46 ; print message following call (in this case NEWLINE!)
+F251 DB &0D,&00 ;message
+F254 RTS ;return
+ ;
+************RETRY AFTER A FAILURE ROUTINE *******************************
+
+F255 JSR &F637 ;search for a specified block
+F258 BNE &F209 ;goto F209
+
+
+
+*********** Read Filename using Command Line Interpreter ****************
+
+;filename pointed to by X and Y
+
+F25A STX &F2 ;OS filename/command line pointer lo
+F25C STY &F3 ;OS filename/command line pointer
+F25E LDY #&00 ;Y=0
+F260 JSR &EA1D ;initialise string
+F263 LDX #&00 ;X=0
+F265 JSR &EA2F ;GSREAD call
+F268 BCS &F277 ;if end of character string F277
+F26A BEQ &F274 ;if 0 found F274
+F26C STA &03D2,X ;else store character in CFS filename area
+F26F INX ;X=X+1
+F270 CPX #&0B ;if X<>11
+F272 BNE &F265 ;then read next
+F274 JMP &EA8F ;else Bad String error
+
+
+
+************* terminate Filename ****************************************
+
+F277 LDA #&00 ;terminate filename with 0
+F279 STA &03D2,X ;
+F27C RTS ;return
+
+
+
+
+*************************************************************************
+* *
+* OSFILE ENTRY *
+* *
+* on entry A determines action *
+* A=0 save block of memory as a file *
+* A=1 write catalogue info for existing file *
+* A=2 write load address only for existing file *
+* A=3 write execution address only for existing file *
+* A=4 write attributes only for existing file *
+* A=5 Read catalogue info, return file type in A *
+* A=6 Delete named file *
+* A=&FF load the named file if lo byte of Exec address=0 use *
+* address in parameter block else files own load address *
+* X,Y point to parameter block *
+* bytes 0,1 filename address, 2-5 load,6-9 exec,A-D length or *
+* start of data for save, 0E End address /attributes *
+*************************************************************************
+
+;parameter block located by XY
+;0/1 Address of Filename terminated by &0D
+;2/4 Load Address of File
+;6/9 Execution Address of File
+;A/D Start address of data for write operations or length of file
+; for read operations
+;E/11 End address of Data; i.e. byte AFTER last byte to be written
+; or file attributes
+;
+;On Entry action is determined by value in A
+;
+;A=0 Save section of memory as named file, write catalogue information
+;A=1 Write catalogue information for named file
+;A=2 Write the LOAD address (only) for the named File
+;A=3 Write the EXECUTION address (only) for the named File
+;A=4 Write the ATTRIBUTES for the named File
+;A=5 Read the named files catalogue information Place file type in A
+;A=6 Delete the named file
+;A=&FF Load the named file and read its catalogue information
+
+F27D PHA ;save A on stack
+F27E STX &C8 ;osfile block pointer lo
+F280 STY &C9 ;osfile block pointer hi
+F282 LDY #&00 ;Y=0
+F284 LDA (&C8),Y ;OSFILE parameter block
+F286 TAX ;X=A
+F287 INY ;Y=Y+1
+F288 LDA (&C8),Y ;OSFILE parameter block
+F28A TAY ;Y=A
+F28B JSR &F25A ;get filename from BUFFER
+F28E LDY #&02 ;Y=2
+
+F290 LDA (&C8),Y ;copy parameters to Cassette block at 3BE/C5
+F292 STA &03BC,Y ;from LOAD and EXEC address
+F295 STA &00AE,Y ;make second copy at B0-B8
+F298 INY ;Y=Y+1
+F299 CPY #&0A ;until Y=10
+F29B BNE &F290 ;
+
+F29D PLA ;get back A
+F29E BEQ &F2A7 ;if A=0 F2A7
+F2A0 CMP #&FF ;else if A<>&FF
+F2A2 BNE &F254 ;RETURN as cassette has no other options
+F2A4 JMP &F1C4 ;load file
+
+
+************** Save a file **********************************************
+
+F2A7 STA &03C6 ;zero block number
+F2AA STA &03C7 ;zero block number hi
+
+F2AD LDA (&C8),Y ;OSFILE parameter block
+F2AF STA &00A6,Y ;store to Zero page copy (&B0 to &B7)
+F2B2 INY ;data start and data end address
+F2B3 CPY #&12 ;until Y=18
+F2B5 BNE &F2AD ;
+F2B7 TXA ;A=X
+F2B8 BEQ &F274 ;if X=0 no filename found so B274 else BAD STRING error
+
+F2BA JSR &FB27 ;Set cassette option sinto (BB),set C7=6
+ ;claim serial system for cassette
+F2BD JSR &F934 ;prompt to start recording
+
+F2C0 LDA #&00 ;A=0
+F2C2 JSR &FBBD ;enable 2nd proc. if present and set up osfile block
+F2C5 JSR &FBE2 ;set up CFS for write operation
+F2C8 SEC ;set carry flag
+F2C9 LDX #&FD ;X=&FD
+
+F2CB LDA &FFB7,X ;set 03C8/A block length and block flag
+F2CE SBC &FFB3,X ;to B4/6-B0/2 the number of pages (blocks) to be
+ ;saved
+F2D1 STA &02CB,X ;
+F2D4 INX ;X=X+1
+F2D5 BNE &F2CB ;
+
+F2D7 TAY ;Y=A
+F2D8 BNE &F2E8 ;if last byte is non zero F2E8 else
+F2DA CPX &03C8 ;compare X with block length
+F2DD LDA #&01 ;A=1
+F2DF SBC &03C9 ;subtract block length hi
+F2E2 BCC &F2E8 ;if carry clear F2E8
+
+F2E4 LDX #&80 ;X=&80
+F2E6 BNE &F2F0 ;jump F2F0
+
+F2E8 LDA #&01 ;A=1
+F2EA STA &03C9 ;block length hi
+F2ED STX &03C8 ;block length
+F2F0 STX &03CA ;block flag
+F2F3 JSR &F7EC ;write block to Tape
+F2F6 BMI &F341 ;return if negative
+F2F8 JSR &F96A ;increment current load address
+F2FB INC &03C6 ;block number
+F2FE BNE &F2C8 ;if not 0 loop back again else
+F300 INC &03C7 ;block number hi
+F303 BNE &F2C8 ;and loop back again
+
+
+
+*************************************************************************
+* *
+* *RUN ENTRY *
+* *
+*************************************************************************
+
+F305 JSR &F25A ;get filename from BUFFER
+F308 LDX #&FF ;X=&FF
+F30A STX &03C2 ;execution address
+F30D JSR &F1C4 ;load file
+F310 BIT &027A ;&FF if tube present
+F313 BPL &F31F ;so if not present F31F else
+F315 LDA &03C4 ;execution address extend
+F318 AND &03C5 ;execution address extend
+F31B CMP #&FF ;if they are NOT both &FF i.e.for base processor
+F31D BNE &F322 ;F322 else
+F31F JMP (&03C2) ; RUN file
+
+F322 LDX #&C2 ;point to execution address
+F324 LDY #&03 ;(&03C2)
+F326 LDA #&04 ;Tube call 4
+F328 JMP &FBC7 ;and issue to Tube to run file
+
+
+*************************************************************************
+* *
+* *CAT ENTRY *
+* *
+*************************************************************************
+
+ ;CASSETTE OPTIONS in &E2
+
+ ;bit 0 input file open
+ ;bit 1 output file open
+ ;bit 2,4,5 not used
+ ;bit 3 current CATalogue status
+ ;bit 6 EOF reached
+ ;bit 7 EOF warning given
+
+F32B LDA #&08 ;A=8
+F32D JSR &F344 ;set status bits from A
+F330 JSR &FB27 ;Set cassette options into (BB),set C7=6
+ ;claim serial system for cassette
+F333 LDA #&00 ;A=0
+F335 JSR &F348 ;read data from CFS/RFS
+F338 JSR &FAFC ;perform read
+F33B LDA #&F7 ;A=&F7
+F33D AND &E2 ;clear bit 3 of CFS status bit
+F33F STA &E2 ;
+F341 RTS ;return
+ ;
+
+F342 LDA #&40 ;set bit 6 of E2 cassette options
+F344 ORA &E2 ;
+F346 BNE &F33F ;and Jump F33F
+
+
+
+********** search routine ***********************************************
+
+F348 PHA ;save A on stack
+F349 LDA &0247 ;filing system flag 0=CFS 2=RFS
+F34C BEQ &F359 ;if CFS F359 else
+F34E JSR &EE13 ;set current Filing System ROM/PHROM
+F351 JSR &EE18 ;get byte from data Romcheck type
+F354 BCC &F359 ;if carry clear F359 else
+F356 CLV ;clear overflow flag
+F357 BVC &F39A ;JUMP F39A
+
+
+*********** cassette routine********************************************
+
+F359 JSR &F77B ;read block header
+F35C LDA &03C6 ;block number
+F35F STA &B4 ;current block no. lo
+F361 LDA &03C7 ;block number hi
+F364 STA &B5 ;current block no. hi
+F366 LDX #&FF ;X=&FF
+F368 STX &03DF ;copy of last read block flag
+F36B INX ;X=X+1
+F36C STX &BA ;current block flag
+F36E BEQ &F376 ;if 0 F376
+
+F370 JSR &FB69 ;inc. current block no.
+F373 JSR &F77B ;read block header
+F376 LDA &0247 ;get filing system flag 0=CFS 2=RFS
+F379 BEQ &F37D ;if CFS F37D
+F37B BVC &F39A ;if V clear F39A
+F37D PLA ;get back A
+F37E PHA ;save A on stack
+F37F BEQ &F3AE ;if A=0 F3AE
+F381 JSR &FA72 ;else check filename header block matches searched Fn
+F384 BNE &F39C ;if so F39C
+F386 LDA #&30 ;else A=30 to clear all but bits 4/5 of current OPTions
+
+F388 AND &BB ;current OPTions
+F38A BEQ &F39A ;if 0 F39A else
+
+F38C LDA &03C6 ;block number
+F38F CMP &B6 ;next block no. lo
+F391 BNE &F39C ;
+F393 LDA &03C7 ;block number hi
+F396 CMP &B7 ;next block no. hi
+F398 BNE &F39C ;
+F39A PLA ;get back A
+F39B RTS ;return
+ ;
+F39C LDA &0247 ;filing system flag 0=CFS 2=RFS
+F39F BEQ &F3AE ;if tape F3AE
+F3A1 JSR &EEAD ;else set ROM displacement address
+
+F3A4 LDA #&FF ;A=&FF
+F3A6 STA &03C6 ;block number
+F3A9 STA &03C7 ;block number hi
+F3AC BNE &F370 ;jump F370
+
+F3AE BVC &F3B5 ;if carry clear F3B5
+F3B0 LDA #&FF ;A=&FF
+F3B2 JSR &F7D7 ;set flags
+F3B5 LDX #&00 ;X=0
+F3B7 JSR &F9D9 ;report 'DATA?'
+F3BA LDA &0247 ;filing system flag 0=CFS 2=RFS
+F3BD BEQ &F3C3 ;
+F3BF BIT &BB ;current OPTions
+F3C1 BVC &F3A1 ;long messages not required if BIT 6 =0
+F3C3 BIT &03CA ;block flag
+F3C6 BMI &F3A4 ;if -ve F3A4
+F3C8 BPL &F370 ;else loop back and do it again
+
+
+
diff --git a/docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/F3CA b/docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/F3CA
new file mode 100644
index 0000000..7ddf502
--- /dev/null
+++ b/docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/F3CA
@@ -0,0 +1 @@
+*************************************************************************
* *
* OSFIND ENTRY *
* file handling *
* *
*************************************************************************
;on entry A determines Action Y may contain file handle or
;X/Y point to filename terminated by &0D in memory
;A=0 closes file in channel Y if Y=0 closes all files
;A=&40 open a file for input (reading) X/Y points to filename
;A=&80 open a file for output (writing) X/Y points to filename
;A=&C0 open a file for input and output (random access)
;ON EXIT Y=0 if no file found else Y=channel number in use for file
;save A X and Y
F3CA STA &BC ;file status or temporary store
F3CC TXA ;A=X
F3CD PHA ;save X on stack
F3CE TYA ;A=Y
F3CF PHA ;save Y on stack
F3D0 LDA &BC ;file status or temporary store
F3D2 BNE &F3F2 ;if A is non zero open a file via F3F2
************ close a file ***********************************************
F3D4 TYA ;A=Y
F3D5 BNE &F3E3 ;if A<> 0 close specified file else close them all
F3D7 JSR &E275 ;close spool/exec files via OSBYTE 77
F3DA JSR &F478 ;tidy up
F3DD LSR &E2 ;CFS status byte is shifted left and right to zero
F3DF ASL &E2 ;bit 0
F3E1 BCC &F3EF ;and if carry clear no input file was open so F3EF
F3E3 LSR ;A contains file handle so shift bit 0 into carry
F3E4 BCS &F3DD ;if carry set close input file
F3E6 LSR ;else shift bit 1 into carry
F3E7 BCS &F3EC ;if carry set close output file
F3E9 JMP &FBB1 ;else report 'Channel Error' as CFS can only support
;1 input and 1 output file
F3EC JSR &F478 ;tidy up
F3EF JMP &F471 ;and exit
************ OPEN A FILE ************************************************
F3F2 JSR &F25A ;get filename from BUFFER
F3F5 BIT &BC ;file status or temporary store
F3F7 BVC &F436 ;check A at input if bit 6 not set its an output file
********* Input files +**************************************************
F3F9 LDA #&00 ;else its an input file
F3FB STA &039E ;BGET buffer offset for next byte
F3FE STA &03DD ;Expected BGET file block number lo
F401 STA &03DE ;expected BGET file block number hi
F404 LDA #&3E ;A=&3E
F406 JSR &F33D ;CFS status =CFS status AND A
F409 JSR &FB1A ;claim serial system and set OPTions
F40C PHP ;save flags on stack
F40D JSR &F631 ;search for file
F410 JSR &F6B4 ;check protection bit of block status and respond
F413 PLP ;get back flags
F414 LDX #&FF ;X=&FF increment to 0 on next instruction
F416 INX ;X=X+1
F417 LDA &03B2,X ;get file name and
F41A STA &03A7,X ;store as BGET filename
F41D BNE &F416 ;until end of filename
F41F LDA #&01 ;A=1 to show file open
F421 JSR &F344 ;set status bits from A
F424 LDA &02EA ;CFS currently resident file block length lo
F427 ORA &02EB ;CFS currently resident file block length hi
F42A BNE &F42F ;if block length is 0
F42C JSR &F342 ;set CFS status bit 3 (EOF reached)
;else
F42F LDA #&01 ;A=1
F431 ORA &0247 ;filing system flag 0=CFS 2=RFS
F434 BNE &F46F ;and exit after restoring registers
******************* open an output file***********************************
F436 TXA ;A=X
F437 BNE &F43C ;if X=0 then zero length filename so
F439 JMP &EA8F ;Bad String error
F43C LDX #&FF ;X=&FF
F43E INX ;X=X+1
;copy sought filename to header block
F43F LDA &03D2,X ;sought filename
F442 STA &0380,X ;BPUT file header block
F445 BNE &F43E ;until A=0 end of filename
F447 LDA #&FF ;A=&FF
F449 LDX #&08 ;X=8
F44B STA &038B,X ;set 38C/93 to &FF
F44E DEX ;X=X-1
F44F BNE &F44B ;
F451 TXA ;A=X=0
F452 LDX #&14 ;X=14
F454 STA &0380,X ;BPUT file header block
F457 INX ;X=X+1
F458 CPX #&1E ;this zeros 394/D
F45A BNE &F454 ;
F45C ROL &0397 ;
F45F JSR &FB27 ;Set cassette optionsinto (BB),set C7=6
;claim serial system for cassette
F462 JSR &F934 ;prompt to start recording
F465 JSR &FAF2 ;enable second processor and reset serial system
F468 LDA #&02 ;A=2
F46A JSR &F344 ;set status bits from A
F46D LDA #&02 ;A=2
F46F STA &BC ;file status or temporary store
F471 PLA ;get back A
F472 TAY ;Y=A
F473 PLA ;get back A
F474 TAX ;X=A
F475 LDA &BC ;file status or temporary store
F477 RTS ;return
;
F478 LDA #&02 ;A=2 clearing all but bit 1 of status byte
F47A AND &E2 ;CFS status byte, with output file open
F47C BEQ &F477 ;if file not open then exit
F47E LDA #&00 ;else A=0
F480 STA &0397 ;setting block length to current value of BPUT offset
F483 LDA #&80 ;A=&80
F485 LDX &039D ;get BPUT buffer ofset
F488 STX &0396 ;setting block length to current value of BPUT offset
F48B STA &0398 ;mark current block as last
F48E JSR &F496 ;save block to tape
F491 LDA #&FD ;A=&FD
F493 JMP &F33D ;CFS status =CFS status AND A
*********** SAVE BLOCK TO TAPE ********************************************
F496 JSR &FB1A ;claim serial system and set OPTions
F499 LDX #&11 ;X=11
F49B LDA &038C,X ;copy header block from 38C-39D
F49E STA &03BE,X ;to 3BE/DF
F4A1 DEX ;X=X-1
F4A2 BPL &F49B ;
;X=&FF
F4A4 STX &B2 ;current load address high word
F4A6 STX &B3 ;current load address high word
F4A8 INX ;X=X+1, (X=0)
F4A9 STX &B0 ;current load address lo byte set to &00
F4AB LDA #&09 ;A=9 to set current load address at &900
F4AD STA &B1 ;current load address
F4AF LDX #&7F ;X=&7F
F4B1 JSR &FB81 ;copy from 301/C+X to 3D2/C sought filename
F4B4 STA &03DF ;copy of last read block flag
F4B7 JSR &FB8E ;switch Motor On
F4BA JSR &FBE2 ;set up CFS for write operation
F4BD JSR &F7EC ;write block to Tape
F4C0 INC &0394 ;block number lo
F4C3 BNE &F4C8 ;
F4C5 INC &0395 ;block number hi
F4C8 RTS ;return
*************************************************************************
* *
* *
* OSBGET get a byte from a file *
* *
* *
*************************************************************************
;on ENTRY Y contains channel number
;on EXIT X and Y are preserved C=0 indicates valid character
; A contains character (or error) A=&FE End Of File
;push X and Y
F4C9 TXA ;A=X
F4CA PHA ;save A on stack
F4CB TYA ;A=Y
F4CC PHA ;save A on stack
F4CD LDA #&01 ;A=1
F4CF JSR &FB9C ;check conditions for OSBGET are OK
F4D2 LDA &E2 ;CFS status byte
F4D4 ASL ;shift bit 7 into carry (EOF warning given)
F4D5 BCS &F523 ;if carry set F523
F4D7 ASL ;shift bit 6 into carry
F4D8 BCC &F4E3 ;if clear EOF not reached F4E3
F4DA LDA #&80 ;else A=&80 setting bit 7 of status byte EOF warning
F4DC JSR &F344 ;set status bits from A
F4DF LDA #&FE ;A=&FE
F4E1 BCS &F51B ;if carry set F51B
F4E3 LDX &039E ;BGET buffer offset for next byte
F4E6 INX ;X=X+1
F4E7 CPX &02EA ;CFS currently resident file block length lo
F4EA BNE &F516 ;read a byte
;else
F4EC BIT &02EC ;block flag of currently resident block
F4EF BMI &F513 ;if bit 7=1 this is the last block so F513 else
F4F1 LDA &02ED ;last character of currently resident block
F4F4 PHA ;save A on stack
F4F5 JSR &FB1A ;claim serial system and set OPTions
F4F8 PHP ;save flags on stack
F4F9 JSR &F6AC ;read in a new block
F4FC PLP ;get back flags
F4FD PLA ;get back A
F4FE STA &BC ;file status or temporary store
F500 CLC ;clear carry flag
F501 BIT &02EC ;block flag of currently resident block
F504 BPL &F51D ;if not last block (bit 7=0)
F506 LDA &02EA ;CFS currently resident file block length lo
F509 ORA &02EB ;CFS currently resident file block length hi
F50C BNE &F51D ;if block size not 0 F51D else
F50E JSR &F342 ;set CFS status bit 6 (EOF reached)
F511 BNE &F51D ;goto F51D
F513 JSR &F342 ;set CFS status bit 6 (EOF reached)
F516 DEX ;X=X-1
F517 CLC ;clear carry flag
F518 LDA &0A00,X ;read byte from cassette buffer
F51B STA &BC ;file status or temporary store
F51D INC &039E ;BGET buffer offset for next byte
F520 JMP &F471 ;exit via F471
F523 BRK ;
F524 DB &DF ;error number
F525 DB 'EOF' ;
F528 BRK ;
*************************************************************************
* *
* *
* OSBPUT WRITE A BYTE TO FILE *
* *
* *
*************************************************************************
;ON ENTRY Y contains channel number A contains byte to be written
F529 STA &C4 ;store A in temorary store
F52B TXA ;and stack X and Y
F52C PHA ;save on stack
F52D TYA ;A=Y
F52E PHA ;save on stack
F52F LDA #&02 ;A=2
F531 JSR &FB9C ;check conditions necessary for OSBPUT are OK
F534 LDX &039D ;BPUT buffer offset for next byte
F537 LDA &C4 ;get back original value of A
F539 STA &0900,X ;Cassette buffer
F53C INX ;X=X+1
F53D BNE &F545 ;if not 0 F545, otherwise buffer is full so
F53F JSR &F496 ;save block to tape
F542 JSR &FAF2 ;enable second processor and reset serial system
F545 INC &039D ;BPUT buffer offset for next byte
F548 LDA &C4 ;get back A
F54A JMP &F46F ;and exit
*************************************************************************
* *
* *
* OSBYTE 139 Select file options *
* *
* *
*************************************************************************
;ON ENTRY Y contains option value X contains option No. see *OPT X,Y
;this applies largely to CFS LOAD SAVE CAT and RUN
;X=1 is message switch
; Y=0 no messages
; Y=1 short messages
; Y=2 gives detailed information on load and execution addresses
;X=2 is error handling
; Y=0 ignore errors
; Y=1 prompt for a retry
; Y=2 abort operation
;X=3 is interblock gap for BPUT# and PRINT#
; Y=0-127 set gap in 1/10ths Second
; Y > 127 use default values
F54D TXA ;A=X
F54E BEQ &F57E ;if A=0 F57E
F550 CPX #&03 ;if X=3
F552 BEQ &F573 ;F573 to set interblock gap
F554 CPY #&03 ;else if Y>2 then BAD COMMAND error
F556 BCS &F55E ;
F558 DEX ;X=X-1
F559 BEQ &F561 ;i.e. if X=1 F561 message control
F55B DEX ;X=X-1
F55C BEQ &F568 ;i.e. if X=2 F568 error response
F55E JMP &E310 ;else E310 to issue Bad Command error
*********** message control *********************************************
F561 LDA #&33 ;to set lower two bits of each nybble as mask
F563 INY ;Y=Y+1
F564 INY ;Y=Y+1
F565 INY ;Y=Y+1
F566 BNE &F56A ;goto F56A
*********** error response *********************************************
F568 LDA #&CC ;setting top two bits of each nybble as mask
F56A INY ;Y=Y+1
F56B AND &E3 ;clear lower two bits of each nybble
F56D ORA &F581,Y ;or with table value
F570 STA &E3 ;store it in &E3
F572 RTS ;return
;setting of &E3
;
;lower nybble sets LOAD options
;upper sets SAVE options
;0000 Ignore errors, no messages
;0001 Abort if error, no messages
;0010 Retry after error, no messages
;1000 Ignore error short messages
;1001 Abort if error short messages
;1010 Retry after error short messages
;1100 Ignore error long messages
;1101 Abort if error long messages
;1110 Retry after error long messages
***********set interblock gap *******************************************
F573 TYA ;A=Y
F574 BMI &F578 ;if Y>127 use default values
F576 BNE &F57A ;if Y<>0 skip next instruction
F578 LDA #&19 ;else A=&19
F57A STA &03D1 ;sequential block gap
F57D RTS ;return
;
F57E TAY ;Y=A
F57F BEQ &F56D ;jump to F56D
*********** DEFAULT OPT VALUES TABLE ************************************
F581 DB &A1 ;%1010 0001
F582 DB &00 ;%0000 0000
F583 DB &22 ;%0010 0010
F584 DB &11 ;%0001 0001
F585 DB &00 ;%0000 0000
F586 DB &88 ;%1000 1000
F587 DB &CC ;%1100 1100
F588 DEC &C0 ;filing system buffer flag
F58A LDA &0247 ;filing system flag 0=CFS 2=RFS
F58D BEQ &F596 ;if CFS F596
F58F JSR &EE51 ;read RFS data rom or Phrom
F592 TAY ;Y=A
F593 CLC ;clear carry flag
F594 BCC &F5B0 ;jump to F5B0
F596 LDA &FE08 ;ACIA status register
F599 PHA ;save A on stack
F59A AND #&02 ;clear all but bits 0,1 A=(0-3)
F59C BEQ &F5A9 ;if 0 F5A9 transmit data register full or RDR empty
F59E LDY &CA ;
F5A0 BEQ &F5A9 ;
F5A2 PLA ;get back A
F5A3 LDA &BD ;character temporary storage
F5A5 STA &FE09 ;ACIA transmit data register
F5A8 RTS ;return
;
F5A9 LDY &FE09 ;read ACIA recieve data register
F5AC PLA ;get back A
F5AD LSR ;bit 2 to carry (data carrier detect)
F5AE LSR ;
F5AF LSR ;
F5B0 LDX &C2 ;progress flag
F5B2 BEQ &F61D ;if &C2=0 exit
F5B4 DEX ;X=X-1
F5B5 BNE &F5BD ;if &C2>1 then F5BD
F5B7 BCC &F61D ;else if carrier tone from cassette detected exit
F5B9 LDY #&02 ;Y=2
F5BB BNE &F61B ;
F5BD DEX ;X=X-1
F5BE BNE &F5D3 ;if &C2>2
F5C0 BCS &F61D ;if carrier tone from cassette not detected exit
F5C2 TYA ;A=Y
F5C3 JSR &FB78 ;set (BE/C0) to 0
F5C6 LDY #&03 ;Y=3
F5C8 CMP #&2A ;is A= to synchronising byte &2A?
F5CA BEQ &F61B ;if so F61B
F5CC JSR &FB50 ;control cassette system
F5CF LDY #&01 ;Y=1
F5D1 BNE &F61B ;goto F61B
F5D3 DEX ;X=X-1
F5D4 BNE &F5E2 ;if &C2>3
F5D6 BCS &F5DC ;
F5D8 STY &BD ;get character read into Y
F5DA BEQ &F61D ;if 0 exit via F61D
F5DC LDA #&80 ;else A=&80
F5DE STA &C0 ;filing system buffer flag
F5E0 BNE &F61D ;and exit
F5E2 DEX ;X=X-1
F5E3 BNE &F60E ;if &C2>4 F60E
F5E5 BCS &F616 ;if carry set F616
F5E7 TYA ;A=Y
F5E8 JSR &F7B0 ;perform CRC
F5EB LDY &BC ;file status or temporary store
F5ED INC &BC ;file status or temporary store
F5EF BIT &BD ;if bit 7 set this is the last byte read
F5F1 BMI &F600 ;so F600
F5F3 JSR &FBD3 ;check if second processor file test tube prescence
F5F6 BEQ &F5FD ;if return with A=0 F5FD
F5F8 STX &FEE5 ;Tube FIFO3
F5FB BNE &F600 ;
F5FD TXA ;A=X restore value
F5FE STA (&B0),Y ;store to current load address
F600 INY ;Y=Y+1
F601 CPY &03C8 ;block length
F604 BNE &F61D ;exit
F606 LDA #&01 ;A=1
F608 STA &BC ;file status or temporary store
F60A LDY #&05 ;Y=5
F60C BNE &F61B ;exit
F60E TYA ;A=Y
F60F JSR &F7B0 ;perform CRC
F612 DEC &BC ;file status or temporary store
F614 BPL &F61D ;exit
F616 JSR &FB46 ;reset ACIA
F619 LDY #&00 ;Y=0
F61B STY &C2 ;progress flag
F61D RTS ;return
*************************************************************************
* *
* FSCV xx - check for end of file *
* *
*************************************************************************
;
F61E PHA ;save A on stack
F61F TYA ;A=Y
F620 PHA ;save Y on stack
F621 TXA ;A=X to put X into Y
F622 TAY ;Y=A
F623 LDA #&03 ;A=3
F625 JSR &FB9C ;confirm file is open
F628 LDA &E2 ;CFS status byte
F62A AND #&40 ;
F62C TAX ;X=A
F62D PLA ;get back A
F62E TAY ;Y=A
F62F PLA ;get back A
F630 RTS ;return
;
F631 LDA #&00 ;A=0
F633 STA &B4 ;current block no. lo
F635 STA &B5 ;current block no. hi
F637 LDA &B4 ;current block no. lo
F639 PHA ;save A on stack
F63A STA &B6 ;next block no. lo
F63C LDA &B5 ;current block no. hi
F63E PHA ;save A on stack
F63F STA &B7 ;next block no. hi
F641 JSR &FA46 ;print message following call
F644 DB 'Searching';
F64C DB &0D ;newline
F64E BRK ;
F64F LDA #&FF ;A=&FF
F651 JSR &F348 ;read data from CFS/RFS
F654 PLA ;get back A
F655 STA &B5 ;current block no. hi
F657 PLA ;get back A
F658 STA &B4 ;current block no. lo
F65A LDA &B6 ;next block no. lo
F65C ORA &B7 ;next block no. hi
F65E BNE &F66D ;
F660 STA &B4 ;current block no. lo
F662 STA &B5 ;current block no. hi
F664 LDA &C1 ;checksum result
F666 BNE &F66D ;
F668 LDX #&B1 ;current load address
F66A JSR &FB81 ;copy from 301/C+X to 3D2/C sought filename
F66D LDA &0247 ;filing system flag 0=CFS 2=RFS
F670 BEQ &F685 ;if cassette F685
F672 BVS &F685 ;
F674 BRK ;
F675 DB &D6 ;Error number
F676 DB 'File Not found'
F684 BRK ;
F685 LDY #&FF ;Y=&FF
F687 STY &03DF ;copy of last read block flag
F68A RTS ;return
;
\ No newline at end of file
diff --git a/docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/F68B b/docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/F68B
new file mode 100644
index 0000000..1f8ba97
--- /dev/null
+++ b/docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/F68B
@@ -0,0 +1 @@
+******** CLOSE EXEC FILE **********************************************
F68B LDA #&00 ;A=0
*************************************************************************
* *
* *EXEC *
* *
*************************************************************************
F68D PHP ;save flags on stack
F68E STY &E6 ;&E6=Y
F690 LDY &0256 ;EXEC file handle
F693 STA &0256 ;EXEC file handle
F696 BEQ &F69B ;if not 0 close file via OSFIND
F698 JSR OSFIND ;
F69B LDY &E6 ;else Y= original Y
F69D PLP ;get back flags
F69E BEQ &F6AB ;if A=0 on entry exit else
F6A0 LDA #&40 ;A=&40
F6A2 JSR OSFIND ;to open an input file
F6A5 TAY ;Y=A
F6A6 BEQ &F674 ;If Y=0 'File not found' else store
F6A8 STA &0256 ;EXEC file handle
F6AB RTS ;return
******* read a block *************************************************
F6AC LDX #&A6 ;X=&A6
F6AE JSR &FB81 ;copy from 301/C+X to 3D2/C sought filename
F6B1 JSR &F77B ;read block header
F6B4 LDA &03CA ;block flag
F6B7 LSR ;A=A/2 bit 0 into carry to check for locked file
F6B8 BCC &F6BD ;if not set then skip next instruction
F6BA JMP &F1F6 ;'locked' file routine
F6BD LDA &03DD ;Expected BGET file block number lo
F6C0 STA &B4 ; current block no. lo
F6C2 LDA &03DE ;expected BGET file block number hi
F6C5 STA &B5 ;current block no. hi
F6C7 LDA #&00 ;A=0
F6C9 STA &B0 ;current load address
F6CB LDA #&0A ;A=&A setting current load address to the CFS/RFS
F6CD STA &B1 ;current load address buffer at &A00
F6CF LDA #&FF ;A=&FF to set other 2 bytes
F6D1 STA &B2 ;current load address high word
F6D3 STA &B3 ;current load address high word
F6D5 JSR &F7D5 ;reset flags
F6D8 JSR &F9B4 ;load file from tape
F6DB BNE &F702 ;if return non zero F702 else
F6DD LDA &0AFF ;get last character from input buffer
F6E0 STA &02ED ;last character currently resident block
F6E3 JSR &FB69 ;inc. current block no.
F6E6 STX &03DD ;expected BGET file block number lo
F6E9 STY &03DE ;expected BGET file block number hi
F6EC LDX #&02 ;X=2
F6EE LDA &03C8,X ;read bytes from block flag/block length
F6F1 STA &02EA,X ;store into current values of above
F6F4 DEX ;X=X-1
F6F5 BPL &F6EE ;until X=-1 (&FF)
F6F7 BIT &02EC ;block flag of currently resident block
F6FA BPL &F6FF ;
F6FC JSR &F249 ;print newline if needed
F6FF JMP &FAF2 ;enable second processor and reset serial system
F702 JSR &F637 ;search for a specified block
F705 BNE &F6B4 ;if NE check for locked condition else
F707 CMP #&2A ;is it Synchronising byte &2A?
F709 BEQ &F742 ;if so F742
F70B CMP #&23 ;else is it &23 (header substitute in ROM files)
F70D BNE &F71E ;if not BAD ROM error
F70F INC &03C6 ;block number
F712 BNE &F717 ;
F714 INC &03C7 ;block number hi
F717 LDX #&FF ;X=&FF
F719 BIT &D9B7 ;to set V & M
F71C BNE &F773 ;and jump (ALWAYS!!) to F773
F71E LDA #&F7 ;clear bit 3 of RFS status (current CAT status)
F720 JSR &F33D ;RFS status =RFS status AND A
F723 BRK ;and cause error
F724 DB &D7 ;error number
F725 DB 'Bad Rom'
F72C BRK ;
**********: pick up a header ********************************************
F72D LDY &FF ;get ESCAPE flag
F72F JSR &FB90 ;switch Motor on
F732 LDA #&01 ;A=1
F734 STA &C2 ;progress flag
F736 JSR &FB50 ;control serial system
F739 JSR &F995 ;confirm ESC not set and CFS not executing
F73C LDA #&03 ;A=3
F73E CMP &C2 ;progress flag
F740 BNE &F739 ;back until &C2=3
F742 LDY #&00 ;Y=0
F744 JSR &FB7C ;zero checksum bytes
F747 JSR &F797 ;get character from file and do CRC
F74A BVC &F766 ;if V clear on exit F766
F74C STA &03B2,Y ;else store
F74F BEQ &F757 ;or if A=0 F757
F751 INY ;Y=Y+1
F752 CPY #&0B ;if Y<>&B
F754 BNE &F747 ;go back for next character
F756 DEY ;Y=Y-1
F757 LDX #&0C ;X=12
F759 JSR &F797 ;get character from file and do CRC
F75C BVC &F766 ;if V clear on exit F766
F75E STA &03B2,X ;else store byte
F761 INX ;X=X+1
F762 CPX #&1F ;if X<>31
F764 BNE &F759 ;goto F759
F766 TYA ;A=Y
F767 TAX ;X=A
F768 LDA #&00 ;A=0
F76A STA &03B2,Y ;store it
F76D LDA &BE ;CRC workspace
F76F ORA &BF ;CRC workspace
F771 STA &C1 ;Checksum result
F773 JSR &FB78 ;set (BE/C0) to 0
F776 STY &C2 ;progress flag
F778 TXA ;A=X
F779 BNE &F7D4 ;
F77B LDA &0247 ;filing system flag 0=CFS 2=RFS
F77E BEQ &F72D ;if cassette F72D
F780 JSR &EE51 ;read RFS data rom or Phrom
F783 CMP #&2B ;is it ROM file terminator?
F785 BNE &F707 ;if not F707
********* terminator found **********************************************
F787 LDA #&08 ;A=8 isolating bit 3 CAT status
F789 AND &E2 ;CFS status byte
F78B BEQ &F790 ;if clera skip next instruction
F78D JSR &F24D ;print CR if CFS not operational
F790 JSR &EE18 ;get byte from data Rom
F793 BCC &F780 ;if carry set F780
F795 CLV ;clear overflow flag
F796 RTS ;return
**************** get character from file and do CRC *******************
;
F797 LDA &0247 ;filing system flag 0=CFS 2=RFS
F79A BEQ &F7AD ;if cassette F7AD
F79C TXA ;A=X to save X and Y
F79D PHA ;save X on stack
F79E TYA ;A=Y
F79F PHA ;save Y on stack
F7A0 JSR &EE51 ;read RFS data rom or Phrom
F7A3 STA &BD ;put it in temporary storage
F7A5 LDA #&FF ;A=&FF
F7A7 STA &C0 ;filing system buffer flag
F7A9 PLA ;get back Y
F7AA TAY ;Y=A
F7AB PLA ;get back X
F7AC TAX ;X=A
F7AD JSR &F884 ;check for Escape and loop till bit 7 of FS buffer
;flag=1
************************** perform CRC **********************************
F7B0 PHP ;save flags on stack
F7B1 PHA ;save A on stack
F7B2 SEC ;set carry flag
F7B3 ROR &CB ;CRC Bit counter
F7B5 EOR &BF ;CRC workspace
F7B7 STA &BF ;CRC workspace
F7B9 LDA &BF ;CRC workspace
F7BB ROL ;A=A*2 C=bit 7
F7BC BCC &F7CA ;
F7BE ROR ;A=A/2
F7BF EOR #&08 ;
F7C1 STA &BF ;CRC workspace
F7C3 LDA &BE ;CRC workspace
F7C5 EOR #&10 ;
F7C7 STA &BE ;CRC workspace
F7C9 SEC ;set carry flag
F7CA ROL &BE ;CRC workspace
F7CC ROL &BF ;CRC workspace
F7CE LSR &CB ;CRC Bit counter
F7D0 BNE &F7B9 ;
F7D2 PLA ;get back A
F7D3 PLP ;get back flags
F7D4 RTS ;return
;
F7D5 LDA #&00 ;A=0
F7D7 STA &BD ;&BD=character temporary storage buffer=0
F7D9 LDX #&00 ;X=0
F7DB STX &BC ;file status or temporary store
F7DD BVC &F7E9 ;
F7DF LDA &03C8 ;block length
F7E2 ORA &03C9 ;block length hi
F7E5 BEQ &F7E9 ;if 0 F7E9
F7E7 LDX #&04 ;else X=4
F7E9 STX &C2 ;filename length/progress flag
F7EB RTS ;return
*************** SAVE A BLOCK ********************************************
F7EC PHP ;save flags on stack
F7ED LDX #&03 ;X=3
F7EF LDA #&00 ;A=0
F7F1 STA &03CB,X ;clear 03CB/E (RFS EOF+1?)
F7F4 DEX ;X=X-1
F7F5 BPL &F7F1 ;
F7F7 LDA &03C6 ;block number
F7FA ORA &03C7 ;block number hi
F7FD BNE &F804 ;if block =0 F804 else
F7FF JSR &F892 ;generate a 5 second delay
F802 BEQ &F807 ;goto F807
F804 JSR &F896 ;generate delay set by interblock gap
F807 LDA #&2A ;A=&2A
F809 STA &BD ;store it in temporary file
F80B JSR &FB78 ;set (BE/C0) to 0
F80E JSR &FB4A ;set ACIA control register
F811 JSR &F884 ;check for Escape and loop till bit 7 of FS buffer
;flag=1
F814 DEY ;Y=Y-1
F815 INY ;Y=Y+1
F816 LDA &03D2,Y ;move sought filename
F819 STA &03B2,Y ;into filename block
F81C JSR &F875 ;transfer byte to CFS and do CRC
F81F BNE &F815 ;if filename not complet then do it again
******: deal with rest of header ****************************************
F821 LDX #&0C ;X=12
F823 LDA &03B2,X ;get filename byte
F826 JSR &F875 ;transfer byte to CFS and do CRC
F829 INX ;X=X+1
F82A CPX #&1D ;until X=29
F82C BNE &F823 ;
F82E JSR &F87B ;save checksum to TAPE reset buffer flag
F831 LDA &03C8 ;block length
F834 ORA &03C9 ;block length hi
F837 BEQ &F855 ;if 0 F855
F839 LDY #&00 ;else Y=0
F83B JSR &FB7C ;zero checksum bytes
F83E LDA (&B0),Y ;get a data byte
F840 JSR &FBD3 ;check if second processor file test tube prescence
F843 BEQ &F848 ;if not F848 else
F845 LDX &FEE5 ;Tube FIFO3
F848 TXA ;A=X
F849 JSR &F875 ;transfer byte to CFS and do CRC
F84C INY ;Y=Y+1
F84D CPY &03C8 ;block length
F850 BNE &F83E ;
F852 JSR &F87B ;save checksum to TAPE reset buffer flag
F855 JSR &F884 ;check for Escape and loop till bit 7 of FS buffer
;flag=1
F858 JSR &F884 ;check for Escape and loop till bit 7 of FS buffer
;flag=1
F85B JSR &FB46 ;reset ACIA
F85E LDA #&01 ;A=1
F860 JSR &F898 ;generate 0.1 * A second delay
F863 PLP ;get back flags
F864 JSR &F8B9 ;update block flag, PRINT filename (& address if reqd)
F867 BIT &03CA ;block flag
F86A BPL &F874 ;is this last block (bit 7 set)?
F86C PHP ;save flags on stack
F86D JSR &F892 ;generate a 5 second delay
F870 JSR &F246 ;sound bell and abort
F873 PLP ;get back flags
F874 RTS ;return
****************** transfer byte to CFS and do CRC **********************
;
F875 JSR &F882 ;save byte to buffer, transfer to CFS & reset flag
F878 JMP &F7B0 ;perform CRC
***************** save checksum to TAPE reset buffer flag ****************
F87B LDA &BF ;CRC workspace
F87D JSR &F882 ;save byte to buffer, transfer to CFS & reset flag
F880 LDA &BE ;CRC workspace
************** save byte to buffer, transfer to CFS & reset flag ********
F882 STA &BD ;store A in temporary buffer
***** check for Escape and loop untill bit 7 of FS buffer flag=1 ***********
F884 JSR &F995 ;confirm ESC not set and CFS not executing
F887 BIT &C0 ;filing system buffer flag
F889 BPL &F884 ;loop until bit 7 of &C0 is set
F88B LDA #&00 ;A=0
F88D STA &C0 ;filing system buffer flag
F88F LDA &BD ;get temporary store byte
F891 RTS ;return
;
****************** generate a 5 second delay ***************************
F892 LDA #&32 ;A=50
F894 BNE &F898 ;generate delay 100ms *A (5 seconds)
*************** generate delay set by interblock gap ********************
F896 LDA &C7 ;get current interblock flag
*************** generate delay ******************************************
F898 LDX #&05 ;X=5
F89A STA &0240 ;CFS timeout counter
F89D JSR &F995 ;confirm ESC not set and CFS not executing
F8A0 BIT &0240 ;CFS timeout counter (decremented each 20ms)
F8A3 BPL &F89D ;if +ve F89D
F8A5 DEX ;X=X-1
F8A6 BNE &F89A ;
F8A8 RTS ;return
;
************: generate screen reports ***********************************
F8A9 LDA &03C6 ;block number
F8AC ORA &03C7 ;block number hi
F8AF BEQ &F8B6 ;if 0 F8B6
F8B1 BIT &03DF ;copy of last read block flag
F8B4 BPL &F8B9 ;update block flag, PRINT filename (& address if reqd)
F8B6 JSR &F249 ;print newline if needed
************** update block flag, PRINT filename (& address if reqd) ****
F8B9 LDY #&00 ;Y=0
F8BB STY &BA ;current block flag
F8BD LDA &03CA ;block flag
F8C0 STA &03DF ;copy of last read block flag
F8C3 JSR &E7DC ;check if free to print message
F8C6 BEQ &F933 ;if A=0 on return Cassette system is busy
F8C8 LDA #&0D ;else A=&0D :carriage return
F8CA JSR OSWRCH ;print it (note no linefeed as it's via OSWRCH)
F8CD LDA &03B2,Y ;get byte from filename
F8D0 BEQ &F8E2 ;if 0 filename is ended
F8D2 CMP #&20 ;if <SPACE
F8D4 BCC &F8DA ;F8DA
F8D6 CMP #&7F ;if less than DELETE
F8D8 BCC &F8DC ;its a printable character for F8DC else
*******************Control characters in RFS/CFS filename ******************
F8DA LDA #&3F ;else A='?'
F8DC JSR OSWRCH ;and print it
F8DF INY ;Y=Y+1
F8E0 BNE &F8CD ;back to get rest of filename
***************** end of filename ***************************************
F8E2 LDA &0247 ;filing system flag 0=CFS 2=RFS
F8E5 BEQ &F8EB ;if cassette F8EB
F8E7 BIT &BB ;test current OPTions
F8E9 BVC &F933 ;if bit 6 clear no,long messages needed F933
F8EB JSR &F991 ;print a space
F8EE INY ;Y=Y+1
F8EF CPY #&0B ;if Y<11 then
F8F1 BCC &F8E2 ;loop again to fill out filename with spaces
F8F3 LDA &03C6 ;block number
F8F6 TAX ;X=A
F8F7 JSR &F97A ;print ASCII equivalent of hex byte
F8FA BIT &03CA ;block flag
F8FD BPL &F933 ;if not end of file return
F8FF TXA ;A=X
F900 CLC ;clear carry flag
F901 ADC &03C9 ;block length hi
F904 STA &CD ;file length counter hi
F906 JSR &F975 ;print space + ASCII equivalent of hex byte
F909 LDA &03C8 ;block length
F90C STA &CC ;file length counter lo
F90E JSR &F97A ;print ASCII equivalent of hex byte
F911 BIT &BB ;current OPTions
F913 BVC &F933 ;if bit 6 clear no long messages required so F933
F915 LDX #&04 ;X=4
F917 JSR &F991 ;print a space
F91A DEX ;X=X-1
F91B BNE &F917 ;loop to print 4 spaces
F91D LDX #&0F ;X=&0F to point to load address
F91F JSR &F927 ;print 4 bytes from CFS block header
F922 JSR &F991 ;print a space
F925 LDX #&13 ;X=&13 point to Execution address
************** print 4 bytes from CFS block header **********************
F927 LDY #&04 ;loop pointer
F929 LDA &03B2,X ;block header
F92C JSR &F97A ;print ASCII equivalent of hex byte
F92F DEX ;X=X-1
F930 DEY ;Y=Y-1
F931 BNE &F929 ;
F933 RTS ;return
;
*********** print prompt for SAVE on TAPE *******************************
F934 LDA &0247 ;filing system flag 0=CFS 2=RFS
F937 BEQ &F93C ;if cassette F93C
F939 JMP &E310 ;else 'Bad Command error message'
F93C JSR &FB8E ;switch Motor On
F93F JSR &FBE2 ;set up CFS for write operation
F942 JSR &E7DC ;check if free to print message
F945 BEQ &F933 ;if not exit else
F947 JSR &FA46 ; print message following call
F94A DB 'RECORD then RETURN';
F95C BRK ;
F95D JSR &F995 ;confirm CFS not operating, nor ESCAPE flag set
************ wait for RETURN key to be pressed **************************
F960 JSR OSRDCH ;wait for keypress
F963 CMP #&0D ;is it &0D (RETURN)
F965 BNE &F95D ;no then do it again
F967 JMP OSNEWL ;output Carriage RETURN and LINE FEED
************* increment current load address ****************************
F96A INC &B1 ;current load address
F96C BNE &F974 ;
F96E INC &B2 ;current load address high word
F970 BNE &F974 ;
F972 INC &B3 ;current load address high word
F974 RTS ;return
;
************* print a space + ASCII equivalent of hex byte **************
F975 PHA ;save A on stack
F976 JSR &F991 ;print a space
F979 PLA ;get back A
************** print ASCII equivalent of hex byte **********************
F97A PHA ;save A on stack
F97B LSR ;/16 to put high nybble in lo
F97C LSR ;
F97D LSR ;
F97E LSR ;
F97F JSR &F983 ;print its ASCII equivalent
F982 PLA ;get back A
F983 CLC ;clear carry flag
F984 AND #&0F ;clear high nybble
F986 ADC #&30 ;Add &30 to convert 0-9 to ASCII A-F to : ; < = > ?
F988 CMP #&3A ;if A< ASC(':')
F98A BCC &F98E ;goto F98E
F98C ADC #&06 ;else add 7 to convert : ; < = > ? to A B C D E F
F98E JMP OSWRCH ;print character and return
******************** print a space *************************************
F991 LDA #&20 ;A=' '
F993 BNE &F98E ;goto F98E to print it
******************** confirm CFS not operating, nor ESCAPE flag set *****
F995 PHP ;save flags on stack
F996 BIT &EB ;CFS Active flag
F998 BMI &F99E ;
F99A BIT &FF ;if ESCAPE condition
F99C BMI &F9A0 ;goto F9A0
F99E PLP ;get back flags
F99F RTS ;return
;
F9A0 JSR &F33B ;close input file
F9A3 JSR &FAF2 ;enable second processor and reset serial system
F9A6 LDA #&7E ;A=&7E (126) Acknowledge ESCAPE
F9A8 JSR OSBYTE ;OSBYTE Call
F9AB BRK ;
F9AC DB &11 ;error 17
F9AD DB 'Escape' ;
F9B3 BRK ;
\ No newline at end of file
diff --git a/docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/F9B4 b/docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/F9B4
new file mode 100644
index 0000000..77fe206
--- /dev/null
+++ b/docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/F9B4
@@ -0,0 +1 @@
+OS SERIES 10
LAST PART
GEOFF COX
****************************** LOAD *************************************
F9B4 TYA ;A=Y
F9B5 BEQ &F9C4 ;
F9B7 JSR &FA46 ; print message following call
F9BA DB &0D ;
F9BB DB 'Loading';
F9C2 DB &0D ;
F9C3 BRK ;
F9C5 STA &BA ;current block flag
F9C6 LDX #&FF ;X=&FF
F9C8 LDA &C1 ;Checksum result
F9CA BNE &F9D9 ;if not 0 F9D9
F9CC JSR &FA72 ;else check filename header block matches searched
;filename if this returns NE then no match
F9CF PHP ;save flags on stack
F9D0 LDX #&FF ;X=&FF
F9D2 LDY #&99 ;Y=&99
F9D4 LDA #&FA ;A=&FA this set Y/A to point to 'File?' FA99
F9D6 PLP ;get back flags
F9D7 BNE &F9F5 ;report a query unexpected file name
F9D9 LDY #&8E ;making Y/A point to 'Data' FA8E for CRC error
F9DB LDA &C1 ;Checksum result
F9DD BEQ &F9E3 ;if 0 F9E3
F9DF LDA #&FA ;A=&FA
F9E1 BNE &F9F5 ;jump to F9F5
F9E3 LDA &03C6 ;block number
F9E6 CMP &B4 ;current block no. lo
F9E8 BNE &F9F1 ;if not eual F9F1
F9EA LDA &03C7 ;block number hi
F9ED CMP &B5 ;current block no. hi
F9EF BEQ &FA04 ;if equal FA04
F9F1 LDY #&A4 ;Y=&A4
F9F3 LDA #&FA ;A=&FA point to 'Block?' error unexpected block no.
;at this point an error HAS occurred
F9F5 PHA ;save A on stack
F9F6 TYA ;A=Y
F9F7 PHA ;save Y on stack
F9F8 TXA ;A=X
F9F9 PHA ;save X on stack
F9FA JSR &F8B6 ;print CR if indicated by current block flag
F9FD PLA ;get back A
F9FE TAX ;X=A
F9FF PLA ;get back A
FA00 TAY ;Y=A
FA01 PLA ;get back A
FA02 BNE &FA18 ;jump to FA18
FA04 TXA ;A=X
FA05 PHA ;save A on stack
FA06 JSR &F8A9 ;report
FA09 JSR &FAD6 ;check loading progress, read another byte
FA0C PLA ;get back A
FA0D TAX ;X=A
FA0E LDA &BE ;CRC workspace
FA10 ORA &BF ;CRC workspace
FA12 BEQ &FA8D ;
FA14 LDY #&8E ;Y=&8E
FA16 LDA #&FA ;A=&FA FA8E points to 'Data?'
FA18 DEC &BA ;current block flag
FA1A PHA ;save A on stack
FA1B BIT &EB ;CFS Active flag
FA1D BMI &FA2C ;if active FA2C
FA1F TXA ;A=X
FA20 AND &0247 ;filing system flag 0=CFS 2=RFS
FA23 BNE &FA2C ;
FA25 TXA ;A=X
FA26 AND #&11 ;
FA28 AND &BB ;current OPTions
FA2A BEQ &FA3C ;ignore errors
FA2C PLA ;get back A
FA2D STA &B9 ;store A on &B9
FA2F STY &B8 ;store Y on &B8
FA31 JSR &F68B ;do *EXEC 0 to tidy up
FA34 LSR &EB ;halve CFS Active flag to clear bit 7
FA36 JSR &FAE8 ;bell, reset ACIA & motor
FA39 JMP (&00B8) ;display selected error report
FA3C PLA ;get back A
FA3D INY ;Y=Y+1
FA3E BNE &FA43 ;
FA40 CLC ;clear carry flag
FA41 ADC #&01 ;Add 1
FA43 PHA ;save A on stack
FA44 TYA ;A=Y
FA45 PHA ;save Y on stack
FA46 JSR &E7DC ;check if free to print message
FA49 TAY ;Y=A
FA4A PLA ;get back A
FA4B STA &B8 ;&B8=8
FA4D PLA ;get back A
FA4E STA &B9 ;&B9=A
FA50 TYA ;A=Y
FA51 PHP ;save flags on stack
FA52 INC &B8 ;
FA54 BNE &FA58 ;
FA56 INC &B9 ;
FA58 LDY #&00 ;Y=0
FA5A LDA (&B8),Y ;get byte
FA5C BEQ &FA68 ;if 0 Fa68
FA5E PLP ;get back flags
FA5F PHP ;save flags on stack
FA60 BEQ &FA52 ;if 0 FA52 to get next character
FA62 JSR OSASCI ;else print
FA65 JMP &FA52 ;and do it again
FA68 PLP ;get back flags
FA69 INC &B8 ;increment pointers
FA6B BNE &FA6F ;
FA6D INC &B9 ;
FA6F JMP (&00B8) ;and print error message so no error condition
;occcurs
************ compare filenames ******************************************
FA72 LDX #&FF ;X=&FF inx will mean X=0
FA74 INX ;X=X+1
FA75 LDA &03D2,X ;sought filename byte
FA78 BNE &FA81 ;if not 0 FA81
FA7A TXA ;else A=X
FA7B BEQ &FA80 ;if X=0 A=0 exit
FA7D LDA &03B2,X ;else A=filename byte
FA80 RTS ;return
;
FA81 JSR &E4E3 ;set carry if byte in A is not upper case Alpha
FA84 EOR &03B2,X ;compare with filename
FA87 BCS &FA8B ;if carry set FA8B
FA89 AND #&DF ;else convert to upper case
FA8B BEQ &FA74 ;and if A=0 filename characters match so do it again
FA8D RTS ;return
;
FA8E BRK ;
FA8F DB &D8 ;error number
FA90 DB 'Data' ;
FA96 BRK ;
FA97 BNE &FAAE ;
FA99 BRK ;
FA9A DB &DB ;error number
FA9B DB 'File?' ;
FAA1 BRK ;
FAA2 BNE &FAAE ;
FAA4 BRK ;
FAA5 DB &DA ;error number
FAA6 DB 'Block?'
FAAD BRK ;
FAAE LDA &BA ;current block flag
FAB0 BEQ &FAD3 ;if 0 FAD3 else
FAB2 TXA ;A=X
FAB3 BEQ &FAD3 ;If X=0 FAD3
FAB5 LDA #&22 ;A=&22
FAB7 BIT &BB ;current OPTions checking bits 1 and 5
FAB9 BEQ &FAD3 ;if neither set no retry so FAD3 else
FABB JSR &FB46 ;reset ACIA
FABE TAY ;Y=A
FABF JSR &FA4A ;print following message
FAC2 DB &0D ;Carriage RETURN
FAC3 DB &07 ;BEEP
FAC4 DB 'Rewind Tape' ;
FACF DW &0D0D ;two more newlines
FAD1 BRK ;
FAD2 RTS ;return
;
FAD3 JSR &F24D ;print CR if CFS not operational
FAD6 LDA &C2 ;filename length/progress flag
FAD8 BEQ &FAD2 ;if 0 return else
FADA JSR &F995 ;confirm ESC not set and CFS not executing
FADD LDA &0247 ;filing system flag 0=CFS 2=RFS
FAE0 BEQ &FAD6 ;if CFS FAD6
FAE2 JSR &F588 ;else set up ACIA etc
FAE5 JMP &FAD6 ;and loop back again
********** sound bell, reset ACIA, motor off ****************************
FAE8 JSR &E7DC ;check if free to print message
FAEB BEQ &FAF2 ;enable second processor and reset serial system
FAED LDA #&07 ;beep
FAEF JSR OSWRCH ;
FAF2 LDA #&80 ;
FAF4 JSR &FBBD ;enable 2nd proc. if present and set up osfile block
FAF7 LDX #&00 ;
FAF9 JSR &FB95 ;switch on motor
FAFC PHP ;save flags on stack
FAFD SEI ;prevent IRQ interrupts
FAFE LDA &0282 ;get serial ULA control register setting
FB01 STA &FE10 ;write to serial ULA control register setting
FB04 LDA #&00 ;A=0
FB06 STA &EA ;store A RS423 timeout counter
FB08 BEQ &FB0B ;jump FB0B
FB0A PHP ;save flags on stacksave flags
FB0B JSR &FB46 ;release ACIA (by &FE08=3)
FB0E LDA &0250 ;get last setting of ACIA
FB11 JMP &E189 ;set ACIA and &250 from A before exit
FB14 PLP ;get back flags
FB15 BIT &FF ;if bit 7of ESCAPE flag not set
FB17 BPL &FB31 ;then FB31
FB19 RTS ;else return as unserviced ESCAPE is pending
*************************************************************************
* *
* Claim serial system for sequential Access *
* *
*************************************************************************
FB1A LDA &E3 ;get cassette filing system options byte
;high nybble used for LOAD & SAVE operations
;low nybble used for sequential access
;0000 Ignore errors, no messages
;0001 Abort if error, no messages
;0010 Retry after error, no messages
;1000 Ignore error short messages
;1001 Abort if error short messages
;1010 Retry after error short messages
;1100 Ignore error long messages
;1101 Abort if error long messages
;1110 Retry after error long messages
FB1C ASL ;move low nybble into high nybble
FB1D ASL ;
FB1E ASL ;
FB1F ASL ;
FB20 STA &BB ;current OPTions save into &BB
FB22 LDA &03D1 ;get sequential block gap
FB25 BNE &FB2F ;goto to &FB2F
*************************************************************************
* *
* claim serial system for cassette etc. *
* *
*************************************************************************
FB27 LDA &E3 ;get cassette filing system options byte
;high nybble used for LOAD & SAVE operations
;low nybble used for sequential access
;0000 Ignore errors, no messages
;0001 Abort if error, no messages
;0010 Retry after error, no messages
;1000 Ignore error short messages
;1001 Abort if error short messages
;1010 Retry after error short messages
;1100 Ignore error long messages
;1101 Abort if error long messages
;1110 Retry after error long messages
FB29 AND #&F0 ;clear low nybble
FB2B STA &BB ;as current OPTions
FB2D LDA #&06 ;set current interblock gap
FB2F STA &C7 ;to 6
FB31 CLI ;allow interrupts
FB32 PHP ;save flags on stack
FB33 SEI ;prevent interrupts
FB34 BIT &024F ;check if RS423 is busy
FB37 BPL &FB14 ;if not FB14
FB39 LDA &EA ;see if RS423 has timed out
FB3B BMI &FB14 ;if not FB14
FB3D LDA #&01 ;else load RS423 timeout counter with
FB3F STA &EA ;1 to indicate that cassette has 6850
FB41 JSR &FB46 ;reset ACIA with &FE80=3
FB44 PLP ;get back flags
FB45 RTS ;return
;
FB46 LDA #&03 ;A=3
FB48 BNE &FB65 ;and exit after resetting ACIA
********************** set ACIA control register **********************
FB4A LDA #&30 ;set current ACIA control register
FB4C STA &CA ;to &30
FB4E BNE &FB63 ;and goto FB63
;if bit 7=0 motor off 1=motor on
***************** control cassette system *******************************
FB50 LDA #&05 ;set &FE10 to 5
FB52 STA &FE10 ;setting a transmit baud rate of 300,motor off
FB55 LDX #&FF ;
FB57 DEX ;delay loop
FB58 BNE &FB57 ;
FB5A STX &CA ;&CA=0
FB5C LDA #&85 ;Turn motor on and keep baud rate at 300 recieve
FB5E STA &FE10 ;19200 transmit
FB61 LDA #&D0 ;A=&D0
FB63 ORA &C6 ;
FB65 STA &FE08 ;set up ACIA control register
FB68 RTS ;returnand return
;
FB69 LDX &03C6 ;block number
FB6C LDY &03C7 ;block number hi
FB6F INX ;X=X+1
FB70 STX &B4 ;current block no. lo
FB72 BNE &FB75 ;
FB74 INY ;Y=Y+1
FB75 STY &B5 ;current block no. hi
FB77 RTS ;return
;
FB78 LDY #&00 ;
FB7A STY &C0 ;filing system buffer flag
*****************set (zero) checksum bytes ******************************
FB7C STY &BE ;CRC workspace
FB7E STY &BF ;CRC workspace
FB80 RTS ;return
;
*********** copy sought filename routine ********************************
FB81 LDY #&FF ;Y=&FF
FB83 INY ;Y=Y+1
FB84 INX ;X=X+1
FB85 LDA &0300,X ;
FB88 STA &03D2,Y ;sought filename
FB8B BNE &FB83 ;until end of filename (0)
FB8D RTS ;return
;
FB8E LDY #&00 ;Y=0
********************** switch Motor on **********************************
FB90 CLI ;allow IRQ interrupts
FB91 LDX #&01 ;X=1
FB93 STY &C3 ;store Y as current file handle
********************: control motor ************************************
FB95 LDA #&89 ;do osbyte 137
FB97 LDY &C3 ;get back file handle (preserved thru osbyte)
FB99 JMP OSBYTE ;turn on motor
****************** confirm file is open ********************************
FB9C STA &BC ;file status or temporary store
FB9E TYA ;A=Y
FB9F EOR &0247 ;filing system flag 0=CFS 2=RFS
FBA2 TAY ;Y=A
FBA3 LDA &E2 ;CFS status byte
FBA5 AND &BC ;file status or temporary store
FBA7 LSR ;A=A/2
FBA8 DEY ;Y=Y-1
FBA9 BEQ &FBAF ;
FBAB LSR ;A=A/2
FBAC DEY ;Y=Y-1
FBAD BNE &FBB1 ;
FBAF BCS &FBFE ;
FBB1 BRK ;
FBB2 DB &DE ;error number
FBB3 DB 'Channel' ;
FBBA BRK ;
************* read from second processor ********************************
FBBB LDA #&01 ;A=1
FBBD JSR &FBD3 ;check if second processor file test tube prescence
FBC0 BEQ &FBFE ;if not exit
FBC2 TXA ;A=X
FBC3 LDX #&B0 ;current load address
FBC5 LDY #&00 ;Y=00
FBC7 PHA ;save A on stack
FBC8 LDA #&C0 ;filing system buffer flag
FBCA JSR &0406 ;and out to TUBE
FBCD BCC &FBCA ;
FBCF PLA ;get back A
FBD0 JMP &0406 ;
*************** check if second processor file test tube prescence ******
FBD3 TAX ;X=A
FBD4 LDA &B2 ;current load address high word
FBD6 AND &B3 ;current load address high word
FBD8 CMP #&FF ;
FBDA BEQ &FBE1 ;if &FF then its for base processor
FBDC LDA &027A ;&FF if tube present
FBDF AND #&80 ;to set bit 7 alone
FBE1 RTS ;return
;
******** control ACIA and Motor *****************************************
FBE2 LDA #&85 ;A=&85
FBE4 STA &FE10 ;write to serial ULA control register setting
FBE7 JSR &FB46 ;reset ACIA
FBEA LDA #&10 ;A=16
FBEC JSR &FB63 ;set ACIA to CFS baud rate
FBEF JSR &F995 ;confirm ESC not set and CFS not executing
FBF2 LDA &FE08 ;read ACIA status register
FBF5 AND #&02 ;clear all but bit 1
FBF7 BEQ &FBEF ;if clear FBEF
FBF9 LDA #&AA ;else A=&AA
FBFB STA &FE09 ;transmit data register
FBFE RTS ;return
;
FBFF BRK ;
\ No newline at end of file
diff --git a/docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/FC00 b/docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/FC00
new file mode 100644
index 0000000..177d500
--- /dev/null
+++ b/docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/FC00
@@ -0,0 +1 @@
+************** FRED 1MHz Bus memory-mapped I/O **************************
FC00 ;test hardware
FC10-13 ;teletext
FC14-1F ;Prestel
FC20-27 ;IEEE interface
FC30 ;
FC40-47 ;winchester disc interface
FC50 ;
FC60 ;
FC70 ;
FC80 ;
FC90 ;
FCA0 ;
FCB0 ;
FCC0 ;
FCD0 ;
FCE0 ;
FCF0 ;
FCFF ;paging register for JIM expansion memory
************** JIM 1MHz Bus memory-expansion page ***********************
FD00-FF ;
FDFE ;Ecosoak Vector
************** SHEILA MOS memory-mapped I/O ***************************
;DEVICE WRITE READ
FE00 ;6845 CRTC address register
FE01 ;6845 CRTC register file
FE02 ;Border colour border colour
FE03 ;
FE04 ;
FE05 ;
FE06 ;
FE07 ;
FE08 ;6850 ACIA control register status register
FE09 ;6850 ACIA transmit data recieve data
FE0A ;
FE0B ;
FE0C ;
FE0D ;
FE0E ;
FE0F ;
FE10 ;SERIAL ULA control register
FE11 ;
FE12 ;
FE13 ;
FE14 ;
FE15 ;
FE16 ;
FE17 ;
FE18 ;68B54 ADLC Disable interrupts Econet station ID
FE19 ;
FE1A ;
FE1B ;
FE1C ;
FE1D ;
FE1E ;
FE1F ;
FE20 ;Video ULA control register
FE21 ;Video ULA palette register palette register
FE22 ;
FE23 ;
FE24 ;
FE25 ;
FE26 ;
FE27 ;
FE28 ;
FE29 ;
FE2A ;
FE2B ;
FE2C ;
FE2D ;
FE2E ;
FE2F ;
FE30 ;ROM latch paged ROM ID write only
FE31 ;ALTAIR RAM protect
FE32 ;
FE33 ;
FE34 ;Shadow RAM B+ only note different OS
FE35 ;
FE36 ;
FE37 ;
FE38 ;
FE39 ;
FE3A ;
FE3B ;
FE3C ;
FE3D ;
FE3E ;
FE3F ;
FE40 ;MOS 6522 VIA Output Register B Input Register B
FE41 ;MOS 6522 VIA Output Register A Input Register A
FE42 ;MOS 6522 VIA data direction register B
FE43 ;MOS 6522 VIA data direction register A
FE44 ;MOS 6522 VIA T1C-L latches T1 low Order counter
FE45 ;MOS 6522 VIA T1C-H counter
FE46 ;MOS 6522 VIA T1L-L low order latches
FE47 ;MOS 6522 VIA T1L-H high order latches
FE48 ;MOS 6522 VIA T2C-L latches T2C-L lo order counter
FE49 ;MOS 6522 VIA T2C-H T2 high order counter
FE4A ;MOS 6522 VIA shift register
FE4B ;MOS 6522 VIA auxilliary control register ACR
FE4C ;MOS 6522 VIA Peripheral control register PCR
FE4D ;MOS 6522 VIA Interrupt flag register IFR
FE4E ;MOS 6522 VIA Interrupt enable register IER
FE4F ;MOS 6522 VIA ORB/IRB but no handshake
FE50 ;
FE51 ;
FE52 ;
FE53 ;
FE54 ;
FE55 ;
FE56 ;
FE57 ;
FE58 ;
FE59 ;
FE5A ;
FE5B ;
FE5C ;
FE5D ;
FE5E ;
FE5F ;
FE60 ;USER 6522 VIA Output Register B Input Register B
FE61 ;USER 6522 VIA Output Register A Input Register A
FE62 ;USER 6522 VIA data direction register B
FE63 ;USER 6522 VIA data direction register A
FE64 ;USER 6522 VIA T1C-L latches T1 low Order counter
FE65 ;USER 6522 VIA T1C-H counter
FE66 ;USER 6522 VIA T1L-L low order latches
FE67 ;USER 6522 VIA T1L-H high order latches
FE68 ;USER 6522 VIA T2C-L latches T2C-L lo order counter
FE69 ;USER 6522 VIA T2C-H T2 high order counter
FE6A ;USER 6522 VIA shift register
FE6B ;USER 6522 VIA auxilliary control register ACR
FE6C ;USER 6522 VIA Peripheral control register PCR
FE6D ;USER 6522 VIA Interrupt flag register IFR
FE6E ;USER 6522 VIA Interrupt enable register IER
FE6F ;USER 6522 VIA ORB/IRB but no handshake
FE70 ;
FE71 ;
FE72 ;
FE73 ;
FE74 ;
FE75 ;
FE76 ;
FE77 ;
FE78 ;
FE79 ;
FE7A ;
FE7B ;
FE7C ;
FE7D ;
FE7E ;
FE7F ;
FE80 ;8271 FDC command register status register
FE81 ;8271 FDC parameter register result register
FE82 ;8271 FDC reset register
FE83 ;8271 FDC illegal illegal
FE84 ;8271 FDC data data
FE85 ;
FE86 ;
FE87 ;
FE88 ;
FE89 ;
FE8A ;
FE8B ;
FE8C ;
FE8D ;
FE8E ;
FE8F ;
FE90 ;
FE91 ;
FE92 ;
FE93 ;
FE94 ;
FE95 ;
FE96 ;
FE97 ;
FE98 ;
FE99 ;
FE9A ;
FE9B ;
FE9C ;
FE9D ;
FE9E ;
FE9F ;
FEA0 ;68B54 ADLC control register 1 status register 1
FEA1 ;68B54 ADLC control register 2/3 status register 2/3
FEA2 ;68B54 ADLC Tx FIFO (frame continue) Rx FIFO
FEA3 ;68B54 ADLC Tx FIFO (frame terminate) Rx FIFO
FEA4 ;
FEA5 ;
FEA6 ;
FEA7 ;
FEA8 ;
FEA9 ;
FEAA ;
FEAB ;
FEAC ;
FEAD ;
FEAE ;
FEAF ;
FEB0 ;
FEB1 ;
FEB2 ;
FEB3 ;
FEB4 ;
FEB5 ;
FEB6 ;
FEB7 ;
FEB8 ;
FEB9 ;
FEBA ;
FEBB ;
FEBC ;
FEBD ;
FEBE ;
FEBF ;
FEC0 ;7002 ADC data latch A/D start status
FEC1 ;7002 ADC hi data byte
FEC2 ;7002 ADC lo data byte
FEC3 ;
FEC4 ;
FEC5 ;
FEC6 ;
FEC7 ;
FEC8 ;
FEC9 ;
FECA ;
FECB ;
FECC ;
FECD ;
FECE ;
FECF ;
FED0 ;
FED1 ;
FED2 ;
FED3 ;
FED4 ;
FED5 ;
FED6 ;
FED7 ;
FED8 ;
FED9 ;
FEDA ;
FEDB ;
FEDC ;
FEDD ;
FEDE ;
FEDF ;
FEE0 ;TUBE FIFO1 status register
FEE1 ;TUBE FIFO1
FEE2 ;TUBE FIFO2 status register
FEE3 ;TUBE FIFO2
FEE4 ;TUBE FIFO3 status register
FEE5 ;TUBE FIFO3
FEE6 ;TUBE FIFO4 status register
FEE7 ;TUBE FIFO4
FEE8 ;
FEE9 ;
FEEA ;
FEEB ;
FEEC ;
FEED ;
FEEE ;
FEEF ;
FEF0 ;
FEF1 ;
FEF2 ;
FEF3 ;
FEF4 ;
FEF5 ;
FEF6 ;
FEF7 ;
FEF8 ;
FEF9 ;
FEFA ;
FEFB ;
FEFC ;
FEFD ;
FEFE ;
FEFF ;
********** EXTENDED VECTOR ENTRY POINTS**********************************
;vectors are pointed to &F000 +vector No. vectors may then be directed thru
;a three byte vector table whose XY address is given by osbyte A8, X=0, Y=&FF
;this is set up as lo-hi byte in ROM and ROM number
FF00 JSR &FF51 ;E USERV
FF03 JSR &FF51 ;E BRKV
FF06 JSR &FF51 ;E IRQ1V
FF09 JSR &FF51 ;E IRQ2V
FF0C JSR &FF51 ;E CLIV
FF0F JSR &FF51 ;E BYTEV
FF12 JSR &FF51 ;E WORDV
FF15 JSR &FF51 ;E WRCHV
FF18 JSR &FF51 ;E RDCHV
FF1B JSR &FF51 ;E FILEV
FF1E JSR &FF51 ;E ARGSV
FF21 JSR &FF51 ;E BGETV
FF24 JSR &FF51 ;E BPUTV
FF27 JSR &FF51 ;E GBPBV
FF2A JSR &FF51 ;E FINDV
FF2D JSR &FF51 ;E FSCV
FF30 JSR &FF51 ;E EVENTV
FF33 JSR &FF51 ;E UPTV
FF36 JSR &FF51 ;E NETV
FF39 JSR &FF51 ;E VDUV
FF3C JSR &FF51 ;E KEYV
FF3F JSR &FF51 ;E INSV
FF42 JSR &FF51 ;E REMV
FF45 JSR &FF51 ;E CNPV
FF48 JSR &FF51 ;E IND1V
FF4B JSR &FF51 ;E IND2V
FF4E JSR &FF51 ;E IND3V
;at this point the stack will hold 4 bytes (at least)
;S 0,1 extended vector address
;S 2,3 address of calling routine
;A,X,Y,P will be as at entry
FF51 PHA ;save A on stack
FF52 PHA ;save A on stack
FF53 PHA ;save A on stack
FF54 PHA ;save A on stack
FF55 PHA ;save A on stack
FF56 PHP ;save flags on stack
FF57 PHA ;save A on stack
FF58 TXA ;A=X
FF59 PHA ;save X on stack
FF5A TYA ;A=Y
FF5B PHA ;save Y on stack
FF5C TSX ;get stack pointer into X (&F2 or less)
FF5D LDA #&FF ;A=&FF
FF5F STA &0108,X ;A
FF62 LDA #&88 ;
FF64 STA &0107,X ;
FF67 LDY &010A,X ;this is VECTOR number*3+2!!
FF6A LDA &0D9D,Y ;lo byte of action address
FF6D STA &0105,X ;store it on stack
FF70 LDA &0D9E,Y ;get hi byte
FF73 STA &0106,X ;store it on stack
;at this point stack has YXAP and action address
;followed by return address and 5 more bytes
FF76 LDA &F4 ;
FF78 STA &0109,X ;store original ROM number below this
FF7B LDA &0D9F,Y ;get new rom number
FF7E STA &F4 ;store it as ram copy
FF80 STA &FE30 ;and switch ti that ROM
FF83 PLA ;get back A
FF84 TAY ;Y=A
FF85 PLA ;get back A
FF86 TAX ;X=A
FF87 PLA ;get back A
FF88 RTI ;get back flags and jump to ROM vectored entry
;leaving return address and 5 more bytes on stack
************ return address from ROM indirection ************************
;at this point stack comprises original ROM number,return from JSR &FF51,
;return from original call the return from FF51 is garbage so;
FF89 PHP ;save flags on stack
FF8A PHA ;save A on stack
FF8B TXA ;A=X
FF8C PHA ;save X on stack
FF8D TSX ; (&F7 or less)
FF8E LDA &0102,X ;STORE A AND P OVER
FF91 STA &0105,X ;return address from (JSR &FF51)
FF94 LDA &0103,X ;hiding garbage by duplicating A and X just saved
FF97 STA &0106,X ;
;now we have
;flags,
;A,
;X,
;Rom no.,
;A,
;flags,
;and original return address on stack
;so
FF9A PLA ;get back X
FF9B TAX ;X=A
FF9C PLA ;get back A lose next two bytes
FF9D PLA ;get back A lose
FF9E PLA ;get back A rom number
FF9F STA &F4 ;store it
FFA1 STA &FE30 ;and set it
FFA4 PLA ;get back A
FFA5 PLP ;get back flags
FFA6 RTS ;return and exit pulling original return address
;from stack
;FFA6 is also default input for CFS OSBPGB, VDUV, IND1V,IND2V,IND3V
;as these functions are not implemented by the OS but may be used
;by software or other filing systems or ROMs
*************************************************************************
* *
* OSBYTE &9D FAST BPUT *
* *
*************************************************************************
FFA7 TXA ;A=X
FFA8 BCS &FFD4 ;carry always set, jump to BPUT
*************************************************************************
* *
* OSBYTE &92 READ A BYTE FROM FRED *
* *
************************************************************************* ;
FFAA LDY &FC00,X ;read a byte from FRED area
FFAD RTS ;return
*************************************************************************
* *
* OSBYTE &94 READ A BYTE FROM JIM *
* *
************************************************************************* ;
;
FFAE LDY &FD00,X ;read a byte from JIM area
FFB1 RTS ;return
*************************************************************************
* *
* OSBYTE &96 READ A BYTE FROM SHEILA *
* *
************************************************************************* ;
;
FFB2 LDY &FE00,X ;read a byte from SHEILA memory mapped I/O area
FFB5 RTS ;return
*********** DEFAULT VECTOR TABLE ****************************************
FFB6 DB 36 ;length of look up table in bytes
FFB7 DB 40 ;low byte of address of this table
FFB8 DB D9 ;high byte of address of this table
**************************************************************************
**************************************************************************
** **
** OPERATING SYSTEM FUNCTION CALLS **
** **
**************************************************************************
**************************************************************************
FFB9 JMP &DC0B ;OSRDRM get a byte from sideways ROM
FFBC JMP &C4C0 ;VDUCHR VDU character output
FFBF JMP &E494 ;OSEVEN generate an EVENT
FFC2 JMP &EA1E ;GSINIT initialise OS string
FFC5 JMP &EA2F ;GSREAD read character from input stream
FFC8 JMP &DEC5 ;NVRDCH non vectored OSRDCH
FFCB JMP &E0A4 ;NVWRCH non vectored OSWRCH
FFCE JMP (&021C) ;OSFIND open or close a file
FFD1 JMP (&021A) ;OSGBPB transfer block to or from a file
FFD4 JMP (&0218) ;OSBPUT save a byte to file
FFD7 JMP (&0216) ;OSBGET get a byte from file
FFDA JMP (&0214) ;OSARGS read or write file arguments
FFDD JMP (&0212) ;OSFILE read or write a file
FFE0 JMP (&0210) ;OSRDCH get a byte from current input stream
FFE3 CMP #&0D ;OSASCI output a byte to VDU stream expanding
FFE5 BNE &FFEE ; carriage returns (&0D) to LF/CR (&0A,&0D)
FFE7 LDA #&0A ;OSNEWL output a CR/LF to VDU stream
FFE9 JSR OSWRCH ;Outputs A followed by CR to VDU stream
FFEC LDA #&0D ;OSWRCR output a CR to VDU stream
FFEE JMP (&020E) ;OSWRCH output a character to the VDU stream
FFF1 JMP (&020C) ;OSWORD perform operation using parameter table
FFF4 JMP (&020A) ;OSBYTE perform operation with single bytes
FFF7 JMP (&0208) ;OSCLI pass string to command line interpreter
*************************************************************************
* *
* 6502 Vectors *
* *
*************************************************************************
FFFA DW &0D00 ;NMI address
FFFC DW &D9CD ;RESET address
FFFE DW &DC1C ;IRQ address
That's it the end of the series and the end of Micronet.
See you on the new system or in the paper mags.
Geoff
\ No newline at end of file
diff --git a/docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/Microbase b/docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/Microbase
new file mode 100644
index 0000000..3251a42
--- /dev/null
+++ b/docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/Microbase
@@ -0,0 +1,1682 @@
+BBC MICROBASE SERIES
+BBC 6502 Machine Code by Geoff Cox
+----------------------------------
+This series was first published on Micronet
+between April and October 1991
+
+The BBC Micro Operating System
+Part One: The moving electron writes
+------------------------------------
+In the last series we reviewed the basics of machine code programming
+using the 6502. You will have noticed that not too many examples of
+programming were given. This is because there are two levels of
+programming on any machine, machine level and operating system level.
+
+Operating Systems
+-----------------
+An operating system is basically a group of routines that sit between
+the user and the electronics of the computer. To illustrate what an
+operating system does we have to turn briefly from the path of the
+series.
+
+We'll imagine that you want to write the letter A on the screen of
+your monitor. First we have to work out the shape of the character and
+slice it horizontally into eight sections, one for each of eight
+screen scanning lines on the monitor.
+
+Now we need to detect when the frame synchronising pulse for the
+monitor is sent by the computer. Next we need to count the line
+synchronising pulses to find the one corresponding to the start of the
+first line of the character.
+
+Then we must time from this pulse to the start of the first line of
+the character, turn on the appropriate electron guns in the monitor
+and turn them off at the correct time for the end of the of the
+character. Finally we have a few microseconds to do it all again for
+the next line. That's more or less what happens fifty times a second
+on your monitor screen.
+
+Mapped Screens
+--------------
+This makes even the easiest task very complex. We can make life easier
+by storing a picture or map of the screen in memory and writing the
+character shape to the appropriate map locations.
+
+The map can then be scanned in synchronisation with the electron beam
+on the monitor. This can either be via a clever piece of electronics
+or a software routine.
+
+To illustrate the BBC map, type the following program on any 6502-
+based BBC without screen RAM shadowing.
+
+10 MODE 0
+20 ?&7D00=65
+
+You should see two little white dots towards the bottom right of the
+screen. Now two dots are not the letter A so if we want to write A we
+have to designthe character and write it to the map. This program does
+just that.
+
+10 MODE 0
+20 FOR A=&7D00 TO &7D07
+30 READ B
+40 ?A=B
+50 NEXT
+60 DATA &3C, &66, &66, &7E
+70 DATA &66, &66, &66, &00
+
+The sharp-eyed among you will have spotted something a little odd
+here. The screen seems to be arranged in blocks of eight bytes in this
+mode. Don't worry about this - it simply makes character table design
+simpler.
+
+Character Tables
+----------------
+We can make life even easier by designing a set of characters and
+putting them in an area of memory where they can be looked up. In the
+BBC B this area is in ROM starting at &C000.
+
+A quick diversion here. If we have to have a series of character
+designs in memory it helps to have a standard method of accessing
+them.
+
+The standard character ordering is called ASCII. A space has ASCII
+number 32 and this is the first "printable" character in the set. The
+last is 127 (Delete). There are eight bytes in each character matrix
+so the design for any character is at &C000+(8*(ASCII - 32)).
+
+This program examines the ROM character table and shows how characters
+are arranged.
+
+10 MODE 0
+20 PRINT "CHARACTER ?"
+30 A$=GET$
+40 PRINT A$
+50 START=(8(ASC(A$)-32))+&C000
+60 FIN=START+7
+70 FOR BYTE=START TO FIN
+80 PEEK=?BYTE
+90 PROC_BIN
+100 PRINT~BYTE;TAB(15);~?BYTE;TAB(20);
+110 NEXT
+120 END
+130 DEFPROC_BIN
+140 A$=""
+150 FOR BIT=7 TO 0 STEP-1
+160 X=(PEEK AND 2^BIT)
+170 IF X>1 THEN A$=A$+"" ELSE A$=A$+"."
+180 NEXT
+190 ENDPROC
+
+As you will often want to write characters on the screen it makes a
+lot of sense to have a little routine to take a character from a
+register and print it on the screen.
+
+The routine will look up a character in the table and print it to the
+appropriate position on the screen. There will also need to be a
+record of the cursor position on the screen.
+
+Routines for printing and moving a cursor on the screen will also be
+useful. You could, of course, write all of these routines yourself as
+part of every program but as the computer manufacturer has to provide
+them in order to tell you the machine is working he usually leaves an
+access point for you to use the routines yourself.
+
+Incidentally if you rewrite the first program but change line 10 to
+read MODE 7 you will see a letter A on the screen.
+
+This is an example of clever electronics. A chip on the BBC board
+contains a character generator. Instead of the character design being
+stored in the screen map the character's ASCII value is stored. This
+is read by the electronics and used to generate characters directly on
+the screen. This allows a 40 x 80 text and block graphics screen to be
+generated in just 1K of RAM.
+
+Using the Operating System
+--------------------------
+The screen handling routines and several others make up an operating
+system. In the BBC micro the series of routines that write a character
+on the screen can be accessed though a point called OSWRCH at &FFFE.
+
+So instead of having to design characters, time lines and do all of
+the other things, you can output a letter A to the screen simply
+using:
+
+LDA #65
+JSR &FFEE ;OSWRCH
+
+and leave the operating system to do the rest.
+
+
+BBC 6502 Machine Code
+Part Two: In the beginning
+--------------------------
+Last week we looked at the reasons for an operating system and how it
+can simplify the programmer's task. Unfortunately you will not always
+be able to use the operating system. There may not be a suitable
+routine or it may be too slow. In these cases you have to write to the
+device itself. So to continue our look at machine code we need to
+examine programming with device handling and the operating system.
+
+This series will attempt to kill two birds with one stone by taking
+avery close look at Acorn's OS 1.20 used on Model Bs.
+
+This changed little for the B+ and Master so while the routines may be
+in a slightly different place the basic system will be the same. The
+Master uses 65C02 code which has a few extra instructions so there may
+be some differences in the length of the code.
+
+What you will need
+------------------
+A disassembler or machine code monitor that can handle 6502 or 65C02
+codes. If If you don't have either you can use:
+
+PRINT ~?address
+
+to get the hexadecimal codes which you can then look up in the back of
+the BBC User Guide to get the relevant command.
+
+Suitable Monitors are EXMON, BBC Monitor or the SYSTEM monitor. (I use
+"Maxim" - Ed.) If you have a single- stepping monitor like one of
+these, you will be able to trace some of the routines for yourself.
+
+For this series we will use standard 6502 mnemonics except that DB and
+DW will be used to show byte assignments rather than EQUS, EQUW and
+EQUB. This is because the disassembler I am using produces these codes
+and it's a lot easier to follow than convoluted BBC-type statements.
+
+First things first
+------------------
+Remember that an operating system is not a program in the usual sense.
+Normal programs have a defined entry and exit routines. An operating
+system can have a large number of entry and exit points as well as
+interlocking routines. So to examine the operating system we need a
+starting point.
+
+The 6502 regards memory as a series of 256-byte pages 0 to &FF (255).
+Any address can be considered to be a page number plus an offset
+within the page. Both figures can be represented by a single byte. So
+address &FF01 is on Page &FF offset 01. The concept of offsets is very
+useful if you ever get involved in 80n86 programming.
+
+The BBC Manual gives a series of system entry points on page FF. Most
+of these are indirected through Page 2 and as we cannot guarantee what
+the contents of Page 2 should be (the vectors can be and are changed)
+these are useless as starting points. This leaves three sensible entry
+points.
+
+6502 Vectors
+FFFA DW &0D00 ;NMI address
+FFFC DW &D9CD ;RESET address
+FFFE DW &DC1C ;IRQ address
+
+The NMI address is in RAM so no joy there, but the other two look
+fine. The best is RESET as this is where the machine starts when it is
+turned on or BREAK is pressed. In the case of Model B and OS 1.20 that
+address is &D9CD, so what happens?
+
+In the beginning
+----------------
+Reset can be effected by turning on the computer or pressing BREAK. If
+it is a power-up then the system VIA and processor are reset
+electronically.
+
+If this is a power on situation then nothing has been set up. The
+first thing that happens when power is turned on is that the 6522
+VIAs, the processor and the floppy disc controller are reset. This is
+done by means of one of three printed circuit tracks. The tracks are
+RSTA, RST and NOTRESET.
+
+RSTA is only connected to the system 6522 Versatile Interface adaptor
+(VIA). This operates through a little resistor/capacitor circuit that
+only works when the power is turned on. The effect of this is that the
+6522 System VIA Interrupt Enable Register (IER) bits 0 to 6 will be
+clear (0) only if the reset is caused by a power on condition.
+
+If the Reset is caused by BREAK being pressed then the machine must
+have been on and therefore one or more of the System VIA IER bits will
+be set (to 1). If one or more bits are set then bit 7 of the VIA will
+also be set. This is used to determine the type of Reset. So let's
+look at the operating system more closely.
+
+D9CD LDA #&40 ;set NMI first instruction to RTI
+D9CF STA &0D00 ;NMI RAM start
+
+RESET is the ultimate Act of God as far as the machine is concerned.
+Anything could be happening so the operating system has to clean up
+the system as its first act.
+
+These first instructions just make sure that if a disc is running no
+more information will be read or written from or to the disc. This
+illustrates why you shouldn't press BREAK when a disc is being
+accessed!
+
+The next section sets up the stack:
+
++
+D9D2 SEI ;disable interrupts just in case
+D9D3 CLD ;clear decimal flag
+D9D4 LDX #&FF ;reset stack to where it should be
+D9D6 TXS ;(&1FF)
+
+Next find out if a power-up reset or a BREAK press by examining the
+System VIA IER register.
+
+D9D7 LDA &FE4E ;read interrupt enable register of the system VIA
+D9DA ASL ;shift bit 7 into carry
+D9DB PHA ;save what's left
+D9DC BEQ &D9E7 ;if Power up A=0 so go to D9E7 to clear memory
+
+That's probably enough for this time. Don't worry! I don't intend to
+do a complete disassembly of the operating system in this series but
+we will follow through the power-on sequence to the end because a lot
+of interesting things happen at this time.
+
+We'll take a look at D9E7 and the next routine in this sequence (D9DE)
+in the next part.
+
+
+BBC 6502 Machine Code
+Part Three: Cleaning up the mess
+--------------------------------
+In the last part we looked at what happens when you press BREAK or
+switch on the machine. We'll now continue with a look at an
+undocumented (at least officially) routine.
+
+The byte at &258 can be used to contain information about what the
+machine should do if BREAK is pressed. FX200,n is used to set this
+byte. If n=2 or n=3 then the memory must be cleared. This is often
+used in program protection.
+
+D9DE LDA &0258 ;else if BREAK pressed read BREAK Action flags (set by FX200,n)
+D9E1 LSR ;divide by 2
+D9E2 CMP #&01 ;if &0258 <> 2 or 3
+D9E4 BNE &DA03 ;then Goto &DA03
+D9E6 LSR ;divide A by 2 again (A=0 if FX200,2/3 else A=n/4
+
+Pages 4-&7F are cleared by a simple loop if &258=2 or 3 or it is a
+power on reset. Look out for the clever way of avoiding problems on
+16K machines.
+
+D9E7 LDX #&04 ;get page to start clearance from (4)
+D9E9 STX &01 ;store it in ZP 01
+D9EB STA &00 ;store A at 00
+D9ED TAY ;and in Y to set loop counter
+ ;LOOP STARTS
+D9EE STA (&00),Y ;clear RAM
+D9F0 CMP &01 ;until page address (in &01) =0
+D9F2 BEQ &D9FD ;
+D9F4 INY ;increment pointer
+D9F5 BNE &D9EE ;if not zero loop round again
+D9F7 INY ;else increment again (Y=1) this avoids overwriting the RTI
+ ;instruction at &D00
+D9F8 INX ;increment X
+D9F9 INC &01 ;increment &01
+D9FB BPL &D9EE ;loop until Page (in 01)=&80 then exit
+
+Note that RAM addressing for 16K loops around to &4000=&00 hence the
+checking of &01 for 00. This avoids overwriting zero page on BREAK
+which would cause the machine to crash!
+
+D9FD STX &028E ;writes marker for available RAM 40 =16K,80=32
+DA00 STX &0284 ;write soft key consistency flag
+
+This routine shows the basic structure of a loop. Those of you who
+program in BASIC will recognise it as a very simple structure:
+
+10 A=A+1
+20 IF A<20 GOTO 10
+
+The loop uses zero page addressing with the target address in 00 and
+01 (Page) and the index in Y.
+
+The loop is exited when the value in 01 becomes negative. Remember
+that all values between 0 and &7F are considered to be positive, so
+the BPL instruction can be used to exit the loop at page &80, the
+first negative number. This is the first of the useful loop techniques
+we'll see in this series.
+
+Notice that the first byte of each page is left unchanged. This is
+useful if you want information to survive a BREAK of this type. This
+clearing of memory is not normally carried out.
+
+Next week we'll have a look at the normal RESET path.
+
+BBC 6502 Machine Code
+Part Four: Cleaning up even more mess
+-------------------------------------
+As we saw last week, a normal warm reset avoids the memory clearance
+and proceeds to set up the System VIA.
+
+DA03 LDX #&0F ;set PORT B data direction register to output on bits
+ ;0-3 and input bits 4-7
+DA05 STX &FE42 ;
+
+The next bit is a little more complicated and is intimately bound up
+with hardware. The function is to set up the addressable latch IC 32
+for peripherals via PORT B.
+
+The latch value is written by writing the value to &FE40 bits 0 to 2
+and either a 1 or 0 to bit 3.
+
+Writing the value + 8 therefore writes a 1 to the latched address,
+otherwise a 0 is written.
+
+Value Peripheral Effect
++ 0 8
+
+0 Sound chip Enabled Disabled
+ Speech Chip
+1 (RS) Low High
+2 (WS) Low High
+2 (WS) Low High
+3 Keyboard
+ Write Disabled Enabled
+4 C0 address
+ modifier Low High
+5 C1 address
+ modifier Low High
+6 Caps LED On Off
+7 Shift LED On Off
+
+C0 and C1 are involved with hardware scroll screen address.
+
+ ;X=&F on entry
+DA08 DEX ;loop start
+DA09 STX &FE40 ;Write latch IC32
+DA0C CPX #&09 ;Is it 9?
+DA0E BCS &DA08 ;If not go back and do it again
+ ;X=8 at this point
+ ;Caps Lock On, SHIFT Lock undetermined
+ ;Keyboard Autoscan on
+ ;Sound disabled (may still sound)
+
+Next the keyboard is scanned to determine the values of the keyboard
+links and whether a Ctrl-Break has been performed.
+
+Remember that although we have spent a lot of time reading this, we
+are probably less than 200 microseconds after BREAK was pressed.
+
+The check for Ctrl-Break is effectively looking for simultaneous
+keypresses.
+
+DA10 INX ;X=9
+DA11 TXA ;A=X
+DA12 JSR &F02A ;Interrogate keyboard
+DA15 CPX #&80 ;for keyboard links 9-2 and CTRL key (1)
+DA17 ROR &FC ;rotate MSB into bit 7 of &FC
+
+DA19 TAX ;Get back value of X for loop
+DA1A DEX ;Decrement it
+DA1B BNE &DA11 ;and if >0 do loop again
+ ;On exit if Carry set link 3 is made
+ ;link 2 = bit 0 of &FC and so on
+ ;If CTRL pressed bit 7 of &FC=1 X=0
+DA1D STX &028D ;Clear last BREAK flag
+DA20 ROL &FC ;CTRL is now in carry &FC is keyboard links
+DA22 JSR &EEEB ;Set LEDs
+ ;Carry set on entry is in bit 7 of A on exit
+DA25 ROR ;Get carry back into carry flag
+
+To review what the operating system has done so far, about 400
+microseconds after a BREAK press or about 2 milliseconds from a power
+on. Memory may have been cleared, NMIs have been short circuited, IRQs
+disabled. The keyboard has been scanned for made links and for Ctrl
+being pressed.
+
+We have also located two important and undocumented subroutines: &F02A
+to scan the keyboard and &EEEB to set the keyboard LEDs.
+
+The F02A routine scans for the key whose code is in X being pressed:
+
+F02A LDY #&03 ;Stop Auto scan
+F02C STY &FE40 ;by writing to system VIA
+F02F LDY #&7F ;Set bits 0 to 6 of port A to input on bit 7.
+ ;Output on bits 0 to 6
+F031 STY &FE43 ;
+F034 STX &FE4F ;Write X to Port A system VIA (key to check)
+F037 LDX &FE4F ;Read back &80 if key pressed (M set)
+F03A RTS ;And return
+
+The routine at &EEEB switches on the selected keyboard lights.
+
+EEEB PHP ;Save flags
+EEEC LDA &025A ;Read keyboard status
+ ;Bit 7=1 shift enabled
+ ;Bit 6=1 control pressed
+ ;Bit 5 =0 shift lock
+ ;Bit 4 =0 Caps lock
+ ;Bit 3 =1 shift pressed
+EEEF LSR ;Shift Caps bit into bit 3
+EEF0 AND #&18 ;Mask out all but 4 and 3
+EEF2 ORA #&06 ;Returns 6 if caps lock OFF &E if on.
+ ;Remember add 8 to the value for the addressable
+ ;latch to send a 1.
+EEF4 STA &FE40 ;Turn on or off caps light if required
+EEF7 LSR ;Bring shift bit into bit 3
+EEF8 ORA #&07 ;
+EEFA STA &FE40 ;Turn on or off shift lock light
+EEFD JSR &F12E ;Set keyboard counter
+EF00 PLA ;Get back flags into A
+EF01 RTS ;Return
+
+In this part we've had a look at subroutines using JSR and RTS, the
+machine code equivalent of GOSUB, PROC or FN. Subroutines are often
+used in machine code to perform such frequently needed functions as
+scanning a keyboard or turning on and off lights.
+
+We've also discovered that the byte at &25A contains the keyboard
+status. Try changing it for yourself. You can therefore use OR and AND
+to set the shift and Caps lock status of the machine for a particular
+program.
+
+Next week we'll examine setting up the default vector table in memory.
+
+BBC 6502 Machine Code
+Part Five: Vectors Victor
+-------------------------
+The next stage is to set up the vectors on page 2.
+
+DA26 LDX #&9C ;
+DA28 LDY #&8D ;
+DA2A PLA ;Get back A from &D9DB
+DA2B BEQ &DA36 ;If A=0 power up reset so go to DA36 with X=&9C
+ ;Y=&8D
+DA2D LDY #&7E ;else let Y=&7E
+DA2F BCC &DA42 ;and if not CTRL- BREAK go to DA42 for a WARM RESET
+DA31 LDY #&87 ;else Y=&87 COLD RESET
+DA33 INC &028D ;&28D=1
+DA36 INC &028D ;&28D=&28D+1
+DA39 LDA &FC ;Get keyboard links set
+DA3B EOR #&FF ;Invert
+DA3D STA &028F ;and store at &28F
+DA40 LDX #&90 ;X=&90
+
+What we have done is to set up the high water marks for the reset of
+vectors.
+
+&28D=0 Warm reset, X=&9C, Y=&7E
+&28D=1 Power up , X=&90, Y=&8D
+&28D=2 Cold reset, X=&9C, Y=&87
+
+DA42 LDA #&00 ;A=0
+DA44 CPX #&CE ;zero &200+X to &2CD
+DA46 BCC &DA4A ;
+DA48 LDA #&FF ;then set &2CE to &2FF to &FF
+DA4A STA &0200,X ;
+DA4D INX ;
+DA4E BNE &DA44 ;
+ ;A=&FF X=0
+
+This is another IF-GOTO loop, but in this case it is a double function
+loop. The test at DA44 to DA46 means that A is 0 only for values of X
+between the high water mark and &CD. Above this value A is set to &FF
+by the instruction at &DA48. This saves a few bytes of space,
+essential when writing a tightly-filled ROM.
+
+The next instructions set up the printer port. The only reason for
+doing this now is to save two bytes. A must be &FF at this point so it
+is used to set up the User VIA for outputs as the printer port.
+
+DA50 STA &FE63 ;Set port A of user VIA to all outputs (printer out)
+DA53 TXA ;A=0
+DA54 LDX #&E2 ;X=&E2
+
+START OF LOOP
+DA56 STA &00,X ;set zero page addresses &E2 to &FF to zero
+DA58 INX ;
+DA59 BNE &DA56 ;X=0
+
+Now set up the vectors in page 2 from the table at &D940:
+
+DA5B LDA &D93F,Y ;copy data from &D93F+Y
+DA5E STA &01FF,Y ;to &1FF+Y
+DA61 DEY ;until
+DA62 BNE &DA5B ;1FF+Y=&200
+
+Note that this is a decrementing loop which, for loops ending when an
+index register reaches zero, is faster and shorter because no compare
+is needed. More space saved!
+
+Now the RS423 port is set up via a subroutine affecting the ACIA.
+(Asynchronous Communications Interface Adaptor)
+
+DA64 LDA #&62 ;A=&62
+DA66 STA &ED ;store in &ED
+DA68 JSR &FB0A ;set up ACIA ;X=0
+
+Now Acorn clears the interrupt and enable registers of both VIAs.
+
+DA6B LDA #&7F ;bit 7 is 0!
+DA6D INX ;
+DA6E STA &FE4D,X ;
+DA71 STA &FE6D,X ;
+DA74 DEX ;
+DA75 BPL &DA6E ;
+ ;This loop only has two passes as X=0 on entry.
+DA77 CLI ;Briefly allow interrupts to clear anything
+ ;pending
+DA78 SEI ;Disallow again NB: all VIA IRQs are disabled
+DA79 BIT &FC ;If bit 6=1 then JSR &F055 as there must be a
+ ;hardware interrupt!
+DA7B BVC &DA80 ;else DA80
+DA7D JSR &F055 ;
+
+What have we here? Another undocumented routine. If bit 6 of &FC is
+set there must have been a hardware interrupt when the SEI occurred.
+
+From the circuit diagram the only place that this IRQ could have come
+from is the 1MHz bus - let's have a look at the routine at &F055.
+
+F055 JMP (&FDFE) ;Jim paged entry vector
+
+So we jump to some piece of hardware on the 1MHz bus. This would
+probably be a ROM which would take over the system at power on and
+Break. This has some very interesting applications. It was designed by
+Acorn to provide a crude Econet facility to allow a batch of machines
+to be functionally tested without the need to install a full Econet
+kit.
+
+Next week we shall examine the VIA bus.
+
+BBC 6502 Machine Code
+Part Six: The VIA bus
+---------------------
+The next interesting routine we find in the BBC operating system is
+the one that sets up the system VIA interrupts. It is located at
+&DA80. Refer to the manual for the meanings of Sheila addresses.
+
+DA80 LDX #&F2 ;Enable interrupts 1,4,5,6 of system VIA
+DA82 STX &FE4E ;
+ ;0 Keyboard enabled as needed
+ ;1 Frame sync pulse
+ ;4 End of A/D conversion
+ ;5 T2 counter (for speech)
+ ;6 T1 counter (10 mSec intervals)
+
+DA85 LDX #&04 ;set system VIA PCR
+DA87 STX &FE4C ;
+ ;CA1 Interrupt on negative edge (Frame sync)
+ ;CA2 Handshake output for keyboard
+ ;CB1 Interrupt on negative edge (end of conversion)
+ ;CB2 Negative edge (Light pen strobe)
+DA8A LDA #&60 ;Set system VIA ACR
+DA8C STA &FE4B ;
+ ;Disable latching
+ ;Disable shift register
+ ;T1 counter continuous interrupts
+ ;T2 counter timed interrupt
+
+DA8F LDA #&0E ;Set system VIA T1 counter (low)
+DA91 STA &FE46 ;
+ ;This becomes effective when T1 hi set
+DA94 STA &FE6C ;Set user VIA PCR
+ ;CA1 interrupt on -ve edge (Printer Acknowledge)
+DA80 LDX #&F2 ;enable interrupts
+ ;CA2 High output (printer strobe)
+ ;CB1 Interrupt on -ve edge (user port)
+ ;CB2 Negative edge (user port)
+DA97 STA &FEC0 ;Set up A/D converter Bits 0 and 1 determine
+ ;channel selected
+ ;If Bit 3=0 it is set for an 8-bit conversion.
+ ;If bit 3=1 12-bit conversion.
+
+Now although the machine now knows how much RAM it has it still
+doesn't know if it's a Model A or Model B, so it does not know if a
+user VIA is present at &FE60-FE6F.
+
+The next routine tests for the presence of a user VIA. The system
+timers are then set up to interrupt every 10mSec. Sound channels are
+cleared and the serial ULA is set up. Then the function keys are
+reset.
+
+Now we need a catalogue of sideways ROMS. This is not a catalogue in
+the conventional sense as the ROM title is always at the same place in
+the ROM itself and can be read from there. It is a catalogue of the
+ROM types and positions.
+
+There is a ROM latch at &FE30. Writing a number between 0 and 15 to
+this switches the corresponding ROM into the area between &8000 and
+&BFFF. A short subroutine does this and maintains a copy of the
+current ROM in zero page at location &F4.
+
+ ;on entry X=required ROM number
+DC16 STX &F4 ;RAM copy of ROM latch
+DC18 STX &FE30 ;Write to ROM latch
+DC1B RTS ;and return
+
+You should use this subroutine if you want to switch ROMs. Now we can
+look at the ROM cataloguing routines;
+
+A ROM is considered to be valid if it contains a string identical to
+astring at location &DF0C in the Operating System ROM.
+
+DF0C DB ')C(' ;
+DF0F DB 0 ;
+
+The location of this string is pointed to by an offset byte located at
+&8007.
+
+;X=0 on entry
+DABD JSR &DC16 ;Set up ROM latch and RAM copy to X
+DAC0 LDX #&03 ;Set X to point to offset in table
+DA80 LDX #&F2 ;Enable interrupts
+DAC2 LDY &8007 ;Get copyright offset from ROM
+DAC5 LDA &8000,Y ;Get first byte
+DAC8 CMP &DF0C,X ;Compare it with table byte
+DACB BNE &DAFB ;If not the same then goto DAFB
+DACD INY ;Point to next byte
+DACE DEX ;(s)
+DACF BPL &DAC5 ;and if still +ve go back to check next byte.
+ ;This point is reached if 4 bytes indicate
+ ;valid ROM
+
+Next the first 1K of each ROM is checked against higher priority ROMs
+to ensure that there are no matches. If a match is found, the lower
+priority ROM is ignored.
+
+A ROM type byte is located at &8006. A catalogue of these bytes is
+held at &2A1-&2B0. If bit 7 of this byte is 0 then the ROM is BASIC.
+The position of this ROM is stored at &24B.
+
+Now the ROMs are catalogued it is time to set up the speech system and
+screen. More about that next week.
+
+BBC 6502 Machine Code
+Part Seven: Talk to me
+----------------------
+The operating system start-up routines next checks the SPEECH system.
+At this point the X register is set to 16 (&10) by previous routines.
+
+This is one of the reasons why this routine is inserted here. Setting
+X to the required value would use two more bytes. This is not much
+space but it can make the difference between all of the OS fitting
+into a single ROM and a complete hardware or software redesign.
+
+DB11 BIT &FE40 ;If bit 7 low then we have speech system fitted
+DB14 BMI &DB27 ;else goto DB27 for screen set up routine.
+DB16 DEC &027B ;(027B)=&FF a RAM flag that indicates that a speech
+ ;chip is present.
+DB19 LDY #&FF ;Y=&FF
+DB1B JSR &EE7F ;Initialise speech generator
+DB1E DEX ;via this
+DB1F BNE &DB19 ;loop
+
+Now X = 0 so:
+
+DB21 STX &FE48 ;Set T2 timer for speech
+DB24 STX &FE49 ;
+
+Screen set-up
+-------------
+X=0 on entry to this routine which gets the default screen mode and
+then goes off to the screen setup routine.
+
+DB27 LDA &028F ;Get back start up options (mode)
+DB2A JSR &C300 ;then jump to initialise screen.
+
+One of the things that I wondered when I got a BBC was how the RESET
+key could possibly act as a soft key. As we all know BREAK acts as
+soft key 10. But the keyboard buffer is cleared by the Reset. Tucked
+away is the five-byte routine that makes the BREAK key act as soft
+key 10.
+
+Soft keys work by inserting a byte greater than 127 into the keyboard
+buffer. &CA is the code for key 10.
+
+DB2D LDY #&CA ;Y=&CA
+DB2F JSR &E4F1 ;to enter this value in the keyboard buffer
+
+Simple isn't it? You can use the routine yourself although further
+investigation will show that E4F1 is part of an OSbyte call. Remember
+that the keyboard buffer is buffer 0.
+
+E4F1 LDX #&00 ;X=0 keyboard buffer
+
+**************************************
+* *
+* OSBYTE 153 Put byte in input *
+* Buffer checking for ESCAPE *
+* *
+**************************************
+
+On entry X = buffer number which is either 0 or 1. If it's 0 then the
+keyboard buffer is selected. If it's 1 then it is the RS423 buffer.
+
+Notice that the JSR to EF41 ensures that ONLY the keyboard buffer can
+be selected. Once again we are looking at coding economy, in this case
+with a specific keyboard buffer entry routine. Y contains the
+character to be written.
+
+E4F3 TXA ;A=buffer number
+E4F4 AND &0245 ;and with RS423 mode (0 treat as keyboard 1 ignore
+ ;Escapes no events no soft keys)
+E4F7 BNE &E4AF ;so if RS423 buffer AND RS423 in normal mode (1) E4AF
+ ;
+E4F9 TYA ;else Y=A character to write
+E4FA EOR &026C ;compare with current escape ASCII code (0=match)
+E4FD ORA &0275 ;or with current ESCAPE status (0=ESC, 1=ASCII)
+E500 BNE &E4A8 ;if ASCII or no match E4A8 to enter byte in buffer
+E502 LDA &0258 ;else get ESCAPE / BREAK action byte
+E505 ROR ;Rotate to get ESCAPE bit into carry
+E506 TYA ;get character back in A
+E507 BCS &E513 ;and if escape disabled exit with carry clear
+E509 LDY #&06 ;else signal EVENT 6 Escape pressed
+E50B JSR &E494 ;
+E50E BCC &E513 ;if event handles ESCAPE then exit with carry clear
+E510 JSR &E674 ;else set ESCAPE flag
+E513 CLC ;clear carry
+E514 RTS ;and exit
+
+This routine will normally be accessed by assembly language
+programmers by OSbyte 138 which calls EF43.
+
+BBC 6502 Machine Code
+Part Eight: Breaker Break
+-------------------------
+One of the 'secret' features of the BBC Micro OS 1.20 when it was
+arrived was the BREAK intercept. This is a useful method of taking
+over the machine and is sometimes used by ROM software.
+
+There are two entry points, entered with the carry flag reset to 0 and
+set to 1 respectively. The first call comes before sideways ROM calls.
+
+Enter BREAK intercept with Carry Clear
+
+DB32 JSR &EAD9 ;check to see if BOOT address is set up if so
+ ;JMP to it
+
+The address &287 is written by OSbyte 247 and the jump addresses in
+&288 and &289 by OSbytes 248 and 249. The machine code for JMP is &4C.
+
+EAD9 LDA &0287 ;get BREAK vector code
+EADC EOR #&4C ;produces 0 if JP (4C) not in &287
+EADE BNE &EAF3 ;if not goto EAF3
+EAE0 JMP &0287 ;else jump to use BREAK code
+EAF3 RTS ;Return
+
+The RTS at the end of another routine is used because it saves code.
+
+Frequently you will find machine code routines where a lot of branches
+go to a single RTS for just this reason. If you are writing your own
+code remember that the RTS must be within range of the branch. One of
+the most common assembler errors is a branch out of range that in turn
+causes more errors when you add an extra RTS.
+
+Obviously at this point the machine could be totally in your control.
+You can return control to the OS with an RTS or just continue on your
+merry way.
+
+Remember that the sideways ROMs don't have any workspace yet and you
+can't really run BASIC or any other language as the workspace will not
+exist. But, assuming that you don't want to do any of this, let's go
+back to the OS routines after testing for BREAK intercept.
+
+DB35 JSR &F140 ;set up cassette options
+DB38 LDA #&81 ;test for tube to FIFO buffer 1
+DB3A STA &FEE0 ;
+DB3D LDA &FEE0 ;
+DB40 ROR ;put bit 0 into carry
+DB41 BCC &DB4D ;if no tube then DB4D
+DB43 LDX #&FF ;else
+DB45 JSR &F168 ;issue ROM service call &FF to initialise TUBE system
+DB48 BNE &DB4D ;if not 0 on exit (tube not initialised) DB4D
+DB4A DEC &027A ;else set tube flag to show its active
+
+Now the Tube is flagged as active, or not as the case may be. We
+continue next week, with the setup routines for the sideways ROMs.
+
+BBC 6502 Machine Code
+Part Nine: A ROM with a view
+-----------------------------
+Now we nearly have a working system, we are, perhaps, 400 milliseconds
+into the Power up routine. Now is the time to set up all of those nice
+sideways ROMs we catalogued earlier.
+
+First we set up workspace and hence the value of BASIC's PAGE
+variable. The call to ROMs is made via F168. This is available to the
+programmer as OSBYTE 143.
+
+A ROM can have a number between 0 and 15 and will have two entry
+points - a Service entry at &8003 and a Language entry at &8000. If
+the ROM does not contain language code it will not have a language
+entry.
+
+ROMs are paged into main memory by writing the ROM number to a latch
+at &FE30. Hardware could be arranged to allow 256 ROMs although the
+operating system does not support this.
+
+The Break Intercept code could be used to make drastic hardware
+modifications like this.
+
+**************************************
+* *
+* OSBYTE 143 *
+* Pass service commands *
+* to sideways ROMs *
+* *
+**************************************
+ ;on entry X=command number
+F168 LDA &F4 ;get current ROM number
+F16A PHA ;store it
+F16B TXA ;command in A
+F16C LDX #&0F ;set X=15
+
+The next bit of code is a countdown loop to send the command code to
+each enabled ROM in turn. The Map at &2A1 is used to decide which ROMs
+are active. Note the use of a countdown loop. This gives code economy
+and explains why the highest ROM number has priority.
+
+F16E INC &02A1,X ;read bit 7 on ROM map (no ROM has type 254 &FE)
+F171 DEC &02A1,X ;
+F174 BPL &F183 ;if not set (+ve result)
+F176 STX &F4 ;else store ROM number in &F4
+F178 STX &FE30 ;switch in paged ROM
+F17B JSR &8003 ;and jump to service entry
+F17E TAX ;on exit put A in X
+F17F BEQ &F186 ;if 0 (command recognised by ROM) reset ROMs & exit
+F181 LDX &F4 ;else point to next lower ROM
+F183 DEX ;
+F184 BPL &F16E ;and go round loop again
+F186 PLA ;get back original ROM number
+F187 STA &F4 ;store it in RAM copy
+F189 STA &FE30 ;select original page
+F18C TXA ;put X back in A
+F18D RTS ;and return
+
+Couldn't be easier! So we can now return to the main body of the
+routine.
+
+DB4D LDY #&0E ;set current value of PAGE
+DB4F LDX #&01 ;issue call to claim absolute workspace
+DB51 JSR &F168 ;via F168
+DB54 LDX #&02 ;send private workspace claim call
+DB56 JSR &F168 ;via F168
+
+OSHWM is OS High Water Mark. The highest address used by the operating
+system.
+
+DB59 STY &0243 ;set primary OSHWM
+DB5C STY &0244 ;set current OSHWM
+DB5F LDX #&FE ;issue call for Tube to explode character set etc.
+DB61 LDY &027A ;Y=FF if tube present else Y=0
+DB64 JSR &F168 ;and make call via F168
+
+We now have the machine set up to enter a language, all the filing
+systems have been set up and the sideways ROMs activated.
+
+Next week we finally start the screen messages.
+
+BBC 6502 Machine Code
+Part Ten: Stringing it along
+-----------------------------
+The next routine shows why the Machine start up message is not always
+seen on third-party kit.
+
+DB67 AND &0267 ;if A=&FE and bit 7 of 0267 is set then continue
+DB6A BPL &DB87 ;else ignore start up message
+DB6C LDY #&02 ;output to screen
+DB6E JSR &DEA9 ;'BBC Computer ' message
+
+Looking at the routine in DEA9 we find a very useful string printing
+routine. Remember that Y = 2 on entry.
+
+DEA9 LDA #&C3 ;point to start &C300
+DEAB STA &FE ;store it
+DEAD LDA #&00 ;point to lo byte
+DEAF STA &FD ;store it and start loop with Y=2
+DEB1 INY ;print character in string
+DEB2 LDA (&FD),Y ;pointed to by &FD/E +Y
+DEB4 JSR OSASCI ;print it expanding Carriage returns
+DEB7 TAX ;store A in X
+DEB8 BNE &DEB1 ;and loop again if not =0
+DEBA RTS ;else exit
+
+Here is the string delimited by BRK. The code for BRK is 00. Y is 3
+when the first character is read so its address is &C303.
+
+C303 DB 13 ;Carriage Return
+C304 DB 'BBC Computer '
+C311 BRK
+
+Notice that the routine uses TAX to set the zero flag which marks the
+end of the string. This is a useful tip.
+
+The next part of the Operating system deals with printing correct
+messages on the screen.
+
+DB71 LDA &028D ;0=warm reset, If a cold reset continue
+DB74 BEQ &DB82 ;
+DB76 LDY #&16 ;by checking length of RAM
+DB78 BIT &028E ;
+DB7B BMI &DB7F ;and either
+DB7D LDY #&11 ;
+DB7F JSR &DEA9 ;finishing message with '16K' or '32K'
+DB82 LDY #&1B ;and two new lines
+DB84 JSR &DEA9 ;
+
+Notice that Y is used to pick the appropriate message.
+
+C312 DB '16K'
+C315 DB 7 ;Bell
+C316 BRK
+C317 DB '32K'
+C31A DB 7 ;Bell
+C31B BRK
+C31C DB 08,0D,0D
+
+Notice the BBC Beep at this point indicates that nearly all set up
+procedures have been finished.
+
+The hum is generated by the Sound channel which is reset as part of
+the start routine. Hence the HUM-BEEP start up. If the machine does
+not start properly the sound signals give a strong clue to the nature
+of the problem. Having got this far the OS gives us another chance to
+take control.
+
+Enter BREAK INTERCEPT ROUTINE WITH CARRY SET (call 1)
+
+DB87 SEC ;
+DB88 JSR &EAD9 ;look for break intercept jump
+ ;SEE EARLIER PART
+
+Next we set up the keyboard lights
+
+DB8B JSR &E9D9 ;set up LEDs in accordance with keyboard status
+
+This is another 'undocumented' OSBYTE call.
+
+**************************************
+* *
+* OSBYTE &76 (118) *
+* SET LEDs to Keyboard Status *
+* *
+**************************************
+;osbyte entry with carry set
+E9D9 PHP ;PUSH P
+E9DA SEI ;DISABLE INTERRUPTS
+E9DB LDA #&40 ;switch on CAPS and SHIFT lock lights
+E9DD JSR &E9EA ;via subroutine
+E9E0 BMI &E9E7 ;if ESCAPE exists (M set) E9E7
+E9E2 CLC ;else clear V and C
+E9E3 CLV ;before calling main keyboard routine to
+E9E4 JSR &F068 ;switch on lights as required
+E9E7 PLP ;get back flags
+E9E8 ROL ;and rotate carry into bit 0
+E9E9 RTS ;Return to calling routine
+ ;
+* Turn on keyboard lights and
+* Test Escape flag
+ ;
+E9EA BCC &E9F5 ;if carry clear
+E9EC LDY #&07 ;switch on shift lock light
+E9EE STY &FE40 ;
+E9F1 DEY ;Y=6
+E9F2 STY &FE40 ;switch on Caps lock light
+E9F5 BIT &FF ;set minus flag if bit 7 of &00FF is set indicating
+E9F7 RTS ;that ESCAPE condition exists, then return
+
+The Keyboard routine continues via the KEYV. This is a little long to
+include here so we'll leave it until a later part. So back to the
+Start up routine next week with the cassette system.
+
+BBC 6502 Machine Code
+Part Eleven: Language!
+----------------------
+Having got the keyboard nicely set up the machine proceeds to
+initialise a filing system and run a !BOOT file if one exists. The
+start up options are already read from the keyboard links.
+
+DB8E PHP ;save flags
+DB8F PLA ;and get back in A
+DB90 LSR ;zero bits 4-7 and bits 0-2 bit 4 which was bit 7
+DB91 LSR ;may be set
+DB92 LSR ;
+DB93 LSR ;
+DB94 EOR &028F ;EOR with start up options which may or may not
+DB97 AND #&08 ;invert bit 4
+DB99 TAY ;Y=A
+DB9A LDX #&03 ;make initialisation call, if Y=0 on entry
+DB9C JSR &F168 ;RUN, EXEC or LOAD !BOOT file from a filing system.
+DB9F BEQ &DBBE ;if a ROM accepts this call then DBBE
+DBA1 TYA ;else put Y in A
+DBA2 BNE &DBB8 ;if Y<>0 DBB8
+DBA4 LDA #&8D ;else set up standard cassette baud rates
+DBA6 JSR &F135 ;via &F135 which is OSBYTE 140.
+DBA9 LDX #&D2 ;
+DBAB LDY #&EA ;
+DBAD DEC &0267 ;decrement ignore start up message flag
+DBB0 JSR OSCLI ;and execute /!BOOT
+DBB3 INC &0267 ;restore start up message flag
+DBB6 BNE &DBBE ;if not zero then DBBE
+DBB8 LDA #&00 ;else A=0
+DBBA TAX ;X=0
+DBBB JSR &F137 ;set tape speed via OSBYTE 140.
+
+We now have an active filing system. The next job is to preserve the
+current language on soft RESET.
+
+DBBE LDA &028D ;get last RESET Type
+DBC1 BNE &DBC8 ;if not soft reset DBC8
+DBC3 LDX &028C ;else get current language ROM address
+DBC6 BPL &DBE6 ;if +ve (language available) then skip search
+ ;routine
+For a cold break we search for the language with the highest priority.
+
+DBC8 LDX #&0F ;set pointer to highest available ROM
+DBCA LDA &02A1,X ;get ROM type from map
+DBCD ROL ;put hi-bit into carry, bit 6 into bit 7
+DBCE BMI &DBE6 ;if bit 7 set then ROM has a language entry so DBE6
+DBD0 DEX ;else search for language until X=&ff
+
+Check for Tube if no language found.
+
+DBD1 BPL &DBCA ;check if tube present
+DBD3 LDA #&00 ;if bit 7 of tube flag is set BMI succeeds
+DBD5 BIT &027A ;and TUBE is connected else
+DBD8 BMI &DC08 ;make error
+
+No language error
+
+DBDA BRK ;
+DBDB DB &F9 ;error number
+DBDC DB 'Language?' ;message
+DBE5 BRK ;
+
+This might seem odd as BRK is handled by the current language BRK
+handler, but we don't have a language! We need to investigate further
+in another part.
+
+DBE6 CLC ;
+
+OSBYTE 142 enter Language ROM at &8000 X=ROM number. Carry is set if
+this is an OSBYTE call and clear if this is an initialisation routine.
+
+DBE7 PHP ;save flags
+DBE8 STX &028C ;put X in current ROM page
+DBEB JSR &DC16 ;select that ROM
+DBEE LDA #&80 ;A=128
+DBF0 LDY #&08 ;Y=8
+DBF2 JSR &DEAB ;display text string held in ROM at &8008,Y
+DBF5 STY &FD ;save Y on exit (end of language string)
+DBF7 JSR OSNEWL ;two line feeds
+DBFA JSR OSNEWL ;are output
+DBFD PLP ;then get back flags
+DBFE LDA #&01 ;A=1 required for language entry
+DC00 BIT &027A ;check if tube exists
+DC03 BMI &DC08 ;and goto DC08 if it does
+DC05 JMP &8000 ;else enter language at &8000
+
+TUBE FOUND enter tube software
+
+DC08 JMP &0400 ;enter tube environment
+
+The Tube initialisation would have read the language across to the
+TUBE usually but it could be loaded by a !BOOT file from the filing
+system initialisation.
+
+The operating system now stops general control of the system and hands
+this to the language which looks after command lines etc. The OS
+however still handles the screen, keyboard and much else.
+
+Notice how every possible eventuality was taken into account during
+the initialisation routine. This is one of the things that made the
+Beeb a very powerful machine.
+
+Next week we'll have a look at the Interrupt code.
+
+BBC 6502 Machine Code
+Part Twelve: Pardon me!
+-----------------------
+We finished the last part at the point where the operating systems
+power up routine handed over control to the language. We'll write our
+own language later in the series but for now let's dive into another
+entry point.
+
+When the processor's IRQ pin (4) goes low (0V) the processor finishes
+off the current instruction and then goes off to run some microcode of
+its own. This checks that the RDY (2) pin is high and that the
+interrupt flag in the status register is 0 (not set). If it is set the
+interrupt is ignored and the processor goes to the next instruction.
+This continues when the IRQ pin is low.
+
+If the flag is clear then the processor stores the program counter and
+status register on the stack and sets the interrupt flag. The 6502
+then gets the address stored in &FFFE and &FFFF and executes this
+instruction next.
+
+If a BRK instruction is found in executing code then the processor
+performs exactly the same actions except that it does not check the
+status register for the interrupt flag, it does set a flag in the
+status register, the BRK flag.
+
+The main entry point for IRQ (and BRK) for OS 1.20 is &DC51.
+
+MAIN IRQ Entry point
+
+;ON ENTRY STACK contains STATUS REGISTER,PCH,PCL
+DC1C STA &FC ;save A
+DC1E PLA ;get back status (flags)
+DC1F PHA ;and save again
+DC20 AND #&10 ;check if BRK flag set
+DC22 BNE &DC27 ;if so goto DC27
+DC24 JMP (&0204) ;else JUMP through IRQ1V
+
+That's pretty straightforward so far. As you can see IRQ1V allows you
+to put your own hardware at a higher priority than anything else in
+the machine.
+
+You can also write your own hardware interrupt handler if you wish.
+This is the flexibility that made the BBC machine so remarkably
+successful among knowledgeable users.
+
+Let's look at the BRK handler now.
+
+* BRK handling routine *
+DC27 TXA ;save X on stack
+DC28 PHA ;
+DC29 TSX ;get status pointer
+DC2A LDA &0103,X ;get Program Counter low byte
+DC2D CLD ;
+DC2E SEC ;set carry
+DC2F SBC #&01 ;subtract 2 (1+carry)
+DC31 STA &FD ;and store it in &FD
+DC33 LDA &0104,X ;get hi byte
+DC36 SBC #&00 ;subtract 1 if necessary
+DC38 STA &FE ;and store in &FE
+DC3A LDA &F4 ;get currently active ROM
+DC3C STA &024A ;and store it in &24A
+DC3F STX &F0 ;store stack pointer in &F0
+DC41 LDX #&06 ;and issue ROM service call 6
+DC43 JSR &F168 ;(User BRK) to ROMs
+ ;now &FD/E points to byte after BRK
+ ;ROMS may use BRK for their own purposes
+ ;and many do!
+
+It's interesting to see what happens with the ROM handler. This is
+also an entry point for OSBYTE 143 so you can use this in your own
+code.
+
+* OSBYTE 143 *
+*Pass service commands to sideways ROMs *
+ ;on entry X=command number
+F168 LDA &F4 ;get current ROM number
+F16A PHA ;store it
+F16B TXA ;command in A
+F16C LDX #&0F ;set X=15
+ ;send commands loop
+F16E INC &02A1,X ;read bit 7 on ROM map (no ROM has
+ ;type 254 &FE)
+F171 DEC &02A1,X ;
+F174 BPL &F183 ;if not set (+ve result)
+F176 STX &F4 ;else store ROM number in &F4
+F178 STX &FE30 ;switch in paged ROM
+F17B JSR &8003 ;and jump to service entry
+F17E TAX ;on exit put A in X
+F17F BEQ &F186 ;if 0 (command recognised by ROM)
+ ;reset ROMs & exit
+F181 LDX &F4 ;else point to next lower ROM
+F183 DEX ;
+F184 BPL &F16E ;and go round loop again
+F186 PLA ;get back original ROM number
+F187 STA &F4 ;store it in RAM copy
+F189 STA &FE30 ;select original page
+F18C TXA ;put X back in A
+F18D RTS ;and return
+
+Useful little routine that. So back to the BRK handler.
+
+DC46 LDX &028C ;get current language
+DC49 JSR &DC16 ;and activate it
+DC4C PLA ;get back original value of X
+DC4D TAX ;
+DC4E LDA &FC ;get back original value of A
+DC50 CLI ;allow interrupts
+DC51 JMP (&0202) ;and JUMP via BRKV (normally into current language)
+
+Next week we'll carry on by taking a look at the BRK handler.
+
+BBC 6502 Machine Code
+Part Thirteen: Give us a BRK
+----------------------------
+BRK is usually handled by the default language (or by a Sideways ROM).
+However, it may be that you are running a machine code program before
+a current language is set up or perhaps your language doesn't handle
+BRK (it should but you never know).
+
+That's when a default BRK handler takes over.
+
+* DEFAULT BRK HANDLER *
+
+DC54 LDY #&00 ;Y=0 to point to byte after BRK
+DC56 JSR &DEB1 ;print message
+
+Let's have a look at the print routine. Remember that the error-
+handling layout is:
+
+BRK
+Error Number (1 byte)
+Message
+BRK
+
+Y plus the address in &FD &FE points to the error message on entry.
+
+DEB1 INY ;point to first ;character in string
+DEB2 LDA (&FD),Y
+DEB4 JSR OSASCI ;print it
+ ;expanding
+ ;Carriage
+ ;returns
+DEB7 TAX ;store A in X to change flags
+DEB8 BNE &DEB1 ;and loop again if not =0
+DEBA RTS ;else exit
+
+A standard print routine, nothing out of the ordinary but nice and
+compact.
+
+You can use this in your own print routines by changing the zero page
+values. Back to the default BRK handler and an interesting bit of
+code.
+
+DC59 LDA &0267 ;if BIT 0 set and DISK EXEC error
+DC5C ROR ;occurs
+DC5D BCS &DC5D ;hang up machine!
+
+Nasty! But the machine has to be in a pretty unusual configuration for
+this to happen. Mind you, setting 0267 then doing a JSR to DC59 would
+confuse the average user.
+
+DC5F JSR OSNEWL ;else print two newlines
+DC62 JSR OSNEWL ;
+DC65 JMP &DBB8 ;and set tape speed before entering the current
+ ;language
+DBB8 LDA #&00 ;else A=0
+DBBA TAX ;X=0
+DBBB JSR &F137 ;set tape speed via OSBYTE 141.
+
+There's the end of the BRK handling code. As I said before this is
+generally handled by the default language but you can arrange for your
+own code or a Sideways ROM to handle it.
+
+Next week we'll return to the interrupt system with a look at the
+default entry point for IRQ1.
+
+BBC 6502 Machine Code
+Part Fourteen: The story so far...
+----------------------------------
+We left the interrupt-handling routine just after it had gone off to
+the IRQ1V vector. If you don't change the vector the code continues
+from DC93.
+
+One very important thing to remember about an interrupt-driven machine
+like the BBC is that the interrupt flag is not set for too long. If it
+is the machine could crash. This means that interrupt routines are
+short and snappy.
+
+* Main IRQ Handling routines, default IRQIV destination *
+
+DC93 CLD ;clear decimal flag
+DC94 LDA &FC ;get original value of A
+DC96 PHA ;save it
+DC97 TXA ;save X
+DC98 PHA ;
+DC99 TYA ;and Y
+DC9A PHA ;on the stack
+ ;note the pre-CMOS code!
+DC9B LDA #&DE ;A=&DE
+DC9D PHA ;store it
+DC9E LDA #&81 ;save &81
+DCA0 PHA ;store it (a RTS will now jump to DE82)
+
+This is quite a useful technique as we will see later. If we now use
+JMP to go to an OS routine we can ensure that the routine, which ends
+with an RTS, causes execution to go to a specified point.
+
+This saves a lot of code as it can be arranged that the first device
+found that called the interrupt will be the only one handled. This, in
+turn, saves time!
+
+We now poll the hardware looking for who caused it. The first routine
+deals with the serial/tape system.
+
+DCA1 CLV ;clear V flag
+DCA2 LDA &FE08 ;get value of status register of ACIA
+DCA5 BVS &DCA9 ;if this was source then DCA9 to process
+DCA7 BPL &DD06 ;else if no interrupt requested DD06
+DCA9 LDX &EA ;read RS423 timeout counter
+DCAB DEX ;decrement it
+DCAC BMI &DCDE ;and if <0 DCDE
+DCAE BVS &DCDD ;else if >&40 DCDD (RTS to DE82)
+DCB0 JMP &F588 ;else read ACIA via F588
+ ;RTS ends routine!!
+DCB3 LDY &FE09 ;read ACIA data
+DCB6 ROL ;
+DCB7 ASL ;
+DCB8 TAX ;X=A
+DCB9 TYA ;A=Y
+DCBA LDY #&07 ;Y=07
+DCBC JMP &E494 ;check and service EVENT 7 RS423 error
+DCBF LDX #&02 ;read RS423 output buffer
+DCC1 JSR &E460 ;
+DCC4 BCC &DCD6 ;if C=0 buffer is not empty goto DCD6
+DCC6 LDA &0285 ;else read printer destination
+DCC9 CMP #&02 ;is it serial printer??
+DCCB BNE &DC68 ;if not DC68
+DCCD INX ;else X=3
+DCCE JSR &E460 ;read printer buffer
+DCD1 ROR &02D2 ;rotate to pass carry into bit 7
+DCD4 BMI &DC68 ;if set then DC68
+DCD6 STA &FE09 ;pass either printer or RS423 data to ACIA
+DCD9 LDA #&E7 ;set timeout counter to stored value
+DCDB STA &EA ;
+DCDD RTS ;and exit (to DE82)
+
+ ;A contains ACIA status
+DCDE AND &0278 ;AND with ACIA bit mask (normally FF)
+DCE1 LSR ;rotate right to put bit 0 in carry
+DCE2 BCC &DCEB ;if carry clear receive register not full so DCEB
+DCE4 BVS &DCEB ;if V is set then DCEB
+DCE6 LDY &0250 ;else Y=ACIA control setting
+DCE9 BMI &DC7D ;if bit 7 set receive interrupt is enabled so DC7D
+
+DCEB LSR ;put BIT 2 of ACIA status into
+DCEC ROR ;carry if set then Data Carrier Detected applies
+DCED BCS &DCB3 ;jump to DCB3
+
+DCEF BMI &DCBF ;if original bit 1 is set TDR is empty so DCBF
+DCF1 BVS &DCDD ;if V is set then exit to DE82
+
+DCF3 LDX #&05 ;X=5
+DCF5 JSR &F168 ;issue ROM call 5 'unrecognised ;interrupt'
+
+We've seen this ROM service routine call before.
+
+DCF8 BEQ &DCDD ;if a ROM recognises it then exit to DE82
+DCFA PLA ;otherwise get back DE82 address from stack
+DCFB PLA ;
+DCFC PLA ;and get back X, Y and A
+DCFD TAY ;
+DCFE PLA ;
+DCFF TAX ;
+DD00 PLA ;
+DD01 STA &FC ;&FC=A
+DD03 JMP (&0206) ;and offer to the user via IRQ2V
+
+That was a little convoluted, to say the least. Next week we look at how the
+VIAs are dealt with.
+
+BBC 6502 Machine Code
+Part Fifteen: Hardware VIA interrupts
+-------------------------------------
+After deciding that it wasn't the ACIA that caused the interrupt, the
+VIAs are the next port of inquisition.
+
+* VIA INTERRUPTS ROUTINES *
+
+DD06 LDA &FE4D ;read system VIA interrupt flag register
+DD09 BPL &DD47 ;if bit 7=0 the VIA has not caused interrupt goto DD47
+
+DD0B AND &0279 ;mask with VIA bit mask
+DD0E AND &FE4E ;and interrupt enable register
+DD11 ROR ;rotate right twice to ;check for IRQ 1 (frame sync)
+
+DD12 ROR ;
+DD13 BCC &DD69 ;if carry clear then no IRQ 1, else IRQ 1 means
+ ;interrupt request 1. This is different from the
+ ;vector IRQ1.
+
+DD15 DEC &0240 ;decrement vertical sync counter
+DD18 LDA &EA ;A=RS423 Timeout counter
+DD1A BPL &DD1E ;if +ve then DD1E
+DD1C INC &EA ;else increment it
+DD1E LDA &0251 ;load flash character counter
+DD21 BEQ &DD3D ;if 0 then flash system is not in use, ignore it
+DD23 DEC &0251 ;else decrement counter
+DD26 BNE &DD3D ;and if not 0 go on past reset routine
+
+This routine resets the flashing character system.
+
+DD28 LDX &0252 ;get mark period count in X
+DD2B LDA &0248 ;current VIDEO ULA control setting in A
+DD2E LSR ;shift bit 0 into C to ;check if first colour
+DD2F BCC &DD34 ;is effective if so C=0. Jump to DD34
+DD31 LDX &0253 ;else get space period count in X
+DD34 ROL ;restore bit
+DD35 EOR #&01 ;and invert it
+DD37 JSR &EA00 ;then change colour
+
+DD3A STX &0251 ;&0251=X resetting the counter
+
+DD3D LDY #&04 ;Y=4 and call E494 to check and implement vertical
+DD3F JSR &E494 ;sync event (4) if necessary
+DD42 LDA #&02 ;A=2
+DD44 JMP &DE6E ;clear interrupt 1 and exit
+
+Remember the RTS routine last time?
+
+* PRINTER INTERRUPT USER VIA 1 *
+
+DD47 LDA &FE6D ;Check USER VIA interrupt flags register
+DD4A BPL &DCF3 ;if +ve USER VIA did not call interrupt
+DD4C AND &0277 ;else check for USER IRQ 1 printer interrupt.
+DD4F AND &FE6E ;
+DD52 ROR ;
+DD53 ROR ;
+DD54 BCC &DCF3 ;if bit 1=0 then no ;interrupt 1 so DCF3
+DD56 LDY &0285 ;else get printer type
+DD59 DEY ;decrement
+DD5A BNE &DCF3 ;if not parallel then :CF3
+DD5C LDA #&02 ;reset interrupt 1 flag
+DD5E STA &FE6D ;
+DD61 STA &FE6E ;disable interrupt 1
+DD64 LDX #&03 ;and output data to parallel printer
+DD66 JMP &E13A ;and exit via RTS
+
+* SYSTEM INTERRUPT 5 Speech *
+
+DD69 ROL ;get bit 5 into bit 7
+DD6A ROL ;
+DD6B ROL ;
+DD6C ROL ;
+DD6D BPL &DDCA ;if not set this is not ;a speech interrupt so DDCA
+DD6F LDA #&20 ;
+DD71 LDX #&00 ;
+DD73 STA &FE4D ;
+DD76 STX &FE49 ;and zero high byte of Timer t2
+DD79 LDX #&08 ;&FB=8
+DD7B STX &FB ;
+DD7D JSR &E45B ;and examine buffer 8
+DD80 ROR &02D7 ;shift carry into bit 7
+DD83 BMI &DDC9 ;and if set buffer is empty so exit
+DD85 TAY ;else Y=A
+DD86 BEQ &DD8D ;
+DD88 JSR &EE6D ;control speech chip
+DD8B BMI &DDC9 ;if negative exit
+DD8D JSR &E460 ;else get a byte from buffer
+DD90 STA &F5 ;store it to indicate speech or file ROM
+DD92 JSR &E460 ;get another byte
+DD95 STA &F7 ;store it
+DD97 JSR &E460 ;and another
+DD9A STA &F6 ;giving address to be accessed in paged ROM
+DD9C LDY &F5 ;Y=&F5
+DD9E BEQ &DDBB ;and if =0 then DDBB
+DDA0 BPL &DDB8 ;else if +ve DDB8
+DDA2 BIT &F5 ;if bit 6 of F5 =1 (&F5)>&40
+DDA4 BVS &DDAB ;then DDAB
+DDA6 JSR &EEBB ;else continue for more speech processing
+DDA9 BVC &DDB2 ;if bit 6 clear then DDB2
+DDAB ASL &F6 ;else double address in &F6/7
+DDAD ROL &F7 ;
+DDAF JSR &EE3B ;and call EE3B
+DDB2 LDY &0261 ;get speech enable/disable flag into Y
+DDB5 JMP &EE7F ;and JMP to EE7F
+
+DDB8 JSR &EE7F ;Call EE7F
+DDBB LDY &F6 ;get address pointer in Y
+DDBD JSR &EE7F ;
+DDC0 LDY &F7 ;get address pointer high in Y
+DDC2 JSR &EE7F ;
+DDC5 LSR &FB ;
+DDC7 BNE &DD7D ;
+DDC9 RTS ;and exit
+
+Next week we continue with a look at the remaining System Interrupts.
+
+BBC 6502 Machine Code
+Part Sixteen: Timers and Keyboard Interrupts
+--------------------------------------------
+The last part showed how the BBC Micro handles some of the system
+interrupt calls. Most of these are pretty routine so we won't continue
+with an interminable list.
+
+The next interesting routines concern how the timers and keyboard
+interrupts are handled.
+
+* SYSTEM INTERRUPT 6 10mS Clock *
+
+DDCA BCC &DE47 ;bit 6 is in carry so if clear there is no 6 so go
+ ;on to DE47
+DDCC LDA #&40 ;Clear interrupt 6
+DDCE STA &FE4D ;
+
+This is the start of the update timers routine, This is interesting
+because of the way that the timer information is stored. It's very
+clever. There are two timer stores, &292-6 and &297-B. These are
+updated by adding 1 to the current timer and storing the result in the
+other, the direction of transfer being changed each time of update.
+
+This ensures that at least one timer is valid at any call as the
+current timer only is read. Other methods would cause inaccuracies if
+a timer was read while being updated.
+
+DDD1 LDA &0283 ;get current system clock store pointer (5,or 10)
+DDD4 TAX ;put A in X
+DDD5 EOR #&0F ;and invert lo nybble (5becomes 10 and vv)
+DDD7 PHA ;store A
+DDD8 TAY ;put A in Y. Carry is always set at this point
+DDD9 LDA &0291,X ;get timer value
+DDDC ADC #&00 ;update it
+DDDE STA &0291,Y ;store result in alternate
+DDE1 DEX ;decrement X
+DDE2 BEQ &DDE7 ;if 0 exit
+DDE4 DEY ;else decrement Y
+DDE5 BNE &DDD9 ;and go back and do next byte
+DDE7 PLA ;get back A
+DDE8 STA &0283 ;and store back in clock pointer (ie. inverse
+ ;previous contents)
+DDEB LDX #&05 ;set loop pointer for countdown timer
+DDED INC &029B,X ;increment byte and
+DDF0 BNE &DDFA ;if not 0 then DDFA
+DDF2 DEX ;else decrement pointer
+DDF3 BNE &DDED ;and if not 0 do it again
+DDF5 LDY #&05 ;process EVENT 5 interrupt timer
+DDF7 JSR &E494 ;
+DDFA LDA &02B1 ;get byte of inkey countdown timer
+DDFD BNE &DE07 ;if not 0 then DE07
+DDFF LDA &02B2 ;else get next byte
+DE02 BEQ &DE0A ;if 0 DE0A
+DE04 DEC &02B2 ;decrement 2B2
+DE07 DEC &02B1 ;and 2B1
+DE0A BIT &02CE ;read bit 7 of envelope processing byte
+DE0D BPL &DE1A ;if 0 then DE1A
+DE0F INC &02CE ;else increment to 0
+DE12 CLI ;allow interrupts
+DE13 JSR &EB47 ;and do routine sound processes
+DE16 SEI ;bar interrupts
+DE17 DEC &02CE ;DEC envelope processing byte back to 0
+DE1A BIT &02D7 ;read speech buffer busy flag
+DE1D BMI &DE2B ;if set speech buffer is empty, skip routine
+DE1F JSR &EE6D ;update speech system variables
+DE22 EOR #&A0 ;
+DE24 CMP #&60 ;
+DE26 BCC &DE2B ;if result >=&60 DE2B
+DE28 JSR &DD79 ;else more speech work
+DE2B BIT &D9B7 ;set V and C
+DE2E JSR &DCA2 ;check if ACIA needs attention
+DE31 LDA &EC ;check if key has been pressed
+DE33 ORA &ED ;
+DE35 AND &0242 ;(this is 0 if keyboard is to be ignored, else
+ ;&FF)
+DE38 BEQ &DE3E ;if 0 ignore keyboard
+DE3A SEC ;else set carry
+DE3B JSR &F065 ;and call keyboard
+DE3E JSR &E19B ;check for data in use defined printer channel
+DE41 BIT &FEC0 ;if ADC bit 6 is set ADC is not busy
+DE44 BVS &DE4A ;so DE4A
+DE46 RTS ;else return
+
+* SYSTEM INTERRUPT 4 ADC end of conversion *
+
+DE47 ROL ;put original bit 4 from FE4D into bit 7 of A
+DE48 BPL &DE72 ;if not set DE72
+DE4A LDX &024C ;else get current ADC channel
+DE4D BEQ &DE6C ;if 0 DE6C
+DE4F LDA &FEC2 ;read low data byte
+DE52 STA &02B5,X ;store it in &2B6,7,8 or 9
+DE55 LDA &FEC1 ;get high data byte
+DE58 STA &02B9,X ;and store it in hi byte
+DE5B STX &02BE ;store in Analogue system flag marking last channel
+DE5E LDY #&03 ;handle event 3 conversion complete
+DE60 JSR &E494 ;
+DE63 DEX ;decrement X
+DE64 BNE &DE69 ;if X=0
+DE66 LDX &024D ;get highest ADC channel present
+DE69 JSR &DE8F ;and start new conversion
+DE6C LDA #&10 ;reset interrupt 4
+DE6E STA &FE4D ;
+DE71 RTS ;and return
+
+* SYSTEM INTERRUPT 0 Keyboard *
+
+DE72 ROL ;get original bit 0 in bit 7 position
+DE73 ROL ;
+DE74 ROL ;
+DE75 ROL ;
+DE76 BPL &DE7F ;if bit 7 clear not a keyboard interrupt
+DE78 JSR &F065 ;else scan keyboard
+DE7B LDA #&01 ;A=1
+DE7D BNE &DE6E ;and off to reset interrupt and exit
+DE7F JMP &DCF3 ;and again a subroutine to exit.
+
+Now we come to the point you've all been waiting for. This mystery
+RTSreturns all subroutines to &DE82.
+
+************** exit routine
+DE82 PLA ;restore registers
+DE83 TAY ;
+DE84 PLA ;
+DE85 TAX ;
+DE86 PLA ;
+DE87 STA &FC ;store A
+
+* IRQ2V default entry *
+
+DE89 LDA &FC ;get back original value of A
+DE8B RTI ;and return to calling routine.
+
+NEXT WEEK: OSBYTE entry.
+
+BBC 6502 Machine Code
+Part Seventeen: The BBC Operating System
+----------------------------------------
+We've been examining the BBC operating system in some detail over the
+last few weeks. Unfortunately the demise of Micronet means that we
+cannot finish completely, as we hoped. So we've put together the next
+twenty weeks' articles in the form of a completely commented
+disassembly of OS 1.20.
+
+This is an excellent example of BBC programming and is full of tips.
+
+Just to remind you of the main points of the software. Entry points
+are pointed to by a jump table in the last six bytes of the ROM.
+
+The font characters are located from &C000 to &C2FF.
+
+OK, so here it is all commented and ready for you to peruse.
+
+Ed says: I have uploaded the series of disassembly articles as ten
+ short TSW files. Look on Micronet on 700100239 (before it's
+ too late!)
+
+ *********** THE END **********
+
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+<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
+<HTML><HEAD>
+<META http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
+<META name="MSSmartTagsPreventParsing" content="True">
+<META name="Author" content="Jonathan Graham Harston">
+<TITLE>BBC OS 1.20 - BBC FAQ</TITLE>
+</HEAD>
+
+<BODY>
+<TABLE width="100%">
+<TR bgcolor="#eeeeaa"><th colspan="2"><font size="+3">BBC OS 1.20 DISASSEMBLY</font></th>
+<TR bgcolor="#ffff66"><TD><SMALL><A href="../"
+target="_top">BBC</A>-><B>OS1-20</B>
+</SMALL><TD align="right">
+<SMALL><A href="http://google.co.uk/custom?domains=mdfs.net&sitesearch=mdfs.net">Search</A>
+</SMALL></TABLE><P>
+
+These files were originally abritarily chopped up into approximately
+18K chunks just for ease of editing. I have rearranged them up into
+more logical function chunks. I am going through them and updating,
+correcting and clarifying the comments.
+
+<P><TT>
+<A href="C000" TYPE="text/plain">C000</A>
+Default character set.<BR>
+<A href="C300" TYPE="text/plain">C300</A>
+VDU startup entry and tables.<BR>
+<A href="C4C0" TYPE="text/plain">C4C0</A>
+VDU Part 1: Main Routine. Control character dispatch,<BR>
+ VDU 1,14,2,21,3,15,4,5,8, scroll text window, VDU 11,9,10,28.<BR>
+<A href="C735" TYPE="text/plain">C735</A>
+VDU Part 2: Read pixel, read pallette,
+VDU 12,30,31,13,16,17,18,20,19<BR>
+ write pallette, VDU 22,23,cursor control, CRTC control, VDU 25,26.<BR>
+<A href="CA39" TYPE="text/plain">CA39</A>
+VDU Part 3: VDU 24,29,127,paged mode,initialisation,<BR>
+ read character, clear screen, *FX20, block cursor.<BR>
+<A href="CDED" TYPE="text/plain">CDED</A>
+VDU Part 4: Scroll, clear, move graphics cursor, plot routines,<BR>
+ plot a point.<BR>
+<A href="D10D" TYPE="text/plain">D10D</A> VDU Part 5<BR>
+<A href="D4BF" TYPE="text/plain">D4BF</A> VDU Part 6<BR>
+<A href="D940" TYPE="text/plain">D940</A>
+System Startup. Default vectors, RESET code, find ROMs and BASIC,<BR>
+ initialise ROMs, enter a language.<BR>
+<A href="DC1C" TYPE="text/plain">DC1C</A> Main IRQ Routines.<BR>
+<A href="DF0C" TYPE="text/plain">DF0C</A> OSCLI and OSWRCH dispatch.<BR>
+<A href="E20E" TYPE="text/plain">E20E</A>
+*SAVE, *LOAD, *SPOOL, *KEY, *FX.<BR>
+<A href="E435" TYPE="text/plain">E435</A>
+Buffer handling, Event handling.<BR>
+<A href="E6B0" TYPE="text/plain">E6B0</A>
+OSBYTE/OSWORD dispatch table, FX9/10, FX2, FX13/14, FX16, INKEY,<BR>
+ ADVAL, OSBYTE handler, OSWORD handler, OSWORD 5/6, FX0.<BR>
+<A href="E887" TYPE="text/plain">E887</A>
+Sound system, SOUND, Speech, BELL, ENVELOPE,<br>
+ OSWORD 3,1,2,0,5 FX1,6,12,11,3,4,166+ FX19,160,18,118, GSTrans.<BR>
+<A href="EAD9" TYPE="text/plain">EAD9</A>
+BIV, *TV, Sound IRQs, Speech.<BR>
+<A href="EEDA" TYPE="text/plain">EEDA</A>
+Keyboard.<BR>
+<A href="F135" TYPE="text/plain">F135</A>
+ROM/Cassette filing system. ARGS, FSC, FILE, RUN, CAT. Pass service calls around ROMs<BR>
+<A href="F3CA" TYPE="text/plain">F3CA</A>
+ROM/Cassette filing system. Save data, FIND, BGET, BPUT, OPT, EOF.<BR>
+<A href="F68B" TYPE="text/plain">F68B</A>
+ROM/Cassette filing system. Read/write blocks, CRC checks.<BR>
+<A href="F9B4" TYPE="text/plain">F9B4</A>
+ROM/Cassette filing system. Load data, housekeeping.<BR>
+<A href="FC00" TYPE="text/plain">FC00</A>
+I/O locations, extended vector handler, MOS entry points.<BR>
+<A href="Microbase" TYPE="text/plain">Microbase</A>
+Introduction to the BBC Operating System.<BR>
+</TT>
+
+<BR>
+<table width="100%" bgcolor="#f0f0b0"><tr><th>This page last updated 11-Aug-2010</th></table>
+
+</BODY>
+</HTML>
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