aboutsummaryrefslogtreecommitdiffstats
path: root/roms/SLOF/board-js2x/slof/freq.fs
diff options
context:
space:
mode:
authorfishsoupisgood <github@madingley.org>2019-04-29 01:17:54 +0100
committerfishsoupisgood <github@madingley.org>2019-05-27 03:43:43 +0100
commit3f2546b2ef55b661fd8dd69682b38992225e86f6 (patch)
tree65ca85f13617aee1dce474596800950f266a456c /roms/SLOF/board-js2x/slof/freq.fs
downloadqemu-master.tar.gz
qemu-master.tar.bz2
qemu-master.zip
Initial import of qemu-2.4.1HEADmaster
Diffstat (limited to 'roms/SLOF/board-js2x/slof/freq.fs')
-rw-r--r--roms/SLOF/board-js2x/slof/freq.fs39
1 files changed, 39 insertions, 0 deletions
diff --git a/roms/SLOF/board-js2x/slof/freq.fs b/roms/SLOF/board-js2x/slof/freq.fs
new file mode 100644
index 00000000..9f1d36d7
--- /dev/null
+++ b/roms/SLOF/board-js2x/slof/freq.fs
@@ -0,0 +1,39 @@
+\ *****************************************************************************
+\ * Copyright (c) 2004, 2008 IBM Corporation
+\ * All rights reserved.
+\ * This program and the accompanying materials
+\ * are made available under the terms of the BSD License
+\ * which accompanies this distribution, and is available at
+\ * http://www.opensource.org/licenses/bsd-license.php
+\ *
+\ * Contributors:
+\ * IBM Corporation - initial implementation
+\ ****************************************************************************/
+
+
+\ Use the HPET to calculate various frequencies.
+
+\ Make HPET run.
+1 10 hpet!
+
+\ Set PMC1 to count CPU cycles.
+f00 mmcr0!
+
+d# 1000000000000000 4 hpet@ / CONSTANT hpet-freq
+
+: get-times tbl@ pmc1@ f0 hpet@ ;
+
+\ Calculate the CPU and TB frequencies.
+: calibrate get-times dup >r swap >r swap >r hpet-freq d# 100 / + >r
+ BEGIN get-times dup r@ < WHILE 3drop REPEAT r> drop
+ rot r> - ffffffff and \ TB
+ rot r> - ffffffff and \ CPU
+ rot r> - >r \ HPET
+ hpet-freq * r@ / swap
+ hpet-freq * r> / ;
+
+: round-to tuck 2/ + over / * ;
+calibrate TO tb-frequency d# 100000000 round-to TO cpu-frequency
+
+\ Stop HPET.
+0 10 hpet!