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| author | Dean Camera <dean@fourwalledcubicle.com> | 2010-07-09 07:24:34 +0000 |
|---|---|---|
| committer | Dean Camera <dean@fourwalledcubicle.com> | 2010-07-09 07:24:34 +0000 |
| commit | c326fe96050cf80992ded7726e9222ac5305a908 (patch) | |
| tree | a6010c6defc7a1705f37f9e7107c04a615b05013 /LUFA | |
| parent | 2b0e86243f8fb4554c037d25fe134592b02d1007 (diff) | |
| download | lufa-c326fe96050cf80992ded7726e9222ac5305a908.tar.gz lufa-c326fe96050cf80992ded7726e9222ac5305a908.tar.bz2 lufa-c326fe96050cf80992ded7726e9222ac5305a908.zip | |
Rewrote the implementation of the SwapEndian_16() and SwapEndian_32() functions so that they compile down in most instances to minimal loads and stores rather than complicated shifts.
Fixed SCSI.c implementations of all the demos/projects casting the block count to a 32-bit temporary before calling SwapEndian_16().
Diffstat (limited to 'LUFA')
| -rw-r--r-- | LUFA/Common/Common.h | 39 | ||||
| -rw-r--r-- | LUFA/ManPages/ChangeLog.txt | 2 |
2 files changed, 36 insertions, 5 deletions
diff --git a/LUFA/Common/Common.h b/LUFA/Common/Common.h index 7fd15554c..76144f94b 100644 --- a/LUFA/Common/Common.h +++ b/LUFA/Common/Common.h @@ -174,7 +174,21 @@ static inline uint16_t SwapEndian_16(uint16_t Word) ATTR_WARN_UNUSED_RESULT ATTR_CONST; static inline uint16_t SwapEndian_16(uint16_t Word) { - return ((Word >> 8) | (Word << 8)); + uint8_t Temp; + + union + { + uint16_t Word; + uint8_t Bytes[2]; + } Data; + + Data.Word = Word; + + Temp = Data.Bytes[0]; + Data.Bytes[0] = Data.Bytes[1]; + Data.Bytes[1] = Temp; + + return Data.Word; } /** Function to reverse the byte ordering of the individual bytes in a 32 bit number. @@ -186,10 +200,25 @@ static inline uint32_t SwapEndian_32(uint32_t DWord) ATTR_WARN_UNUSED_RESULT ATTR_CONST; static inline uint32_t SwapEndian_32(uint32_t DWord) { - return (((DWord & 0xFF000000) >> 24) | - ((DWord & 0x00FF0000) >> 8) | - ((DWord & 0x0000FF00) << 8) | - ((DWord & 0x000000FF) << 24)); + uint8_t Temp; + + union + { + uint32_t DWord; + uint8_t Bytes[4]; + } Data; + + Data.DWord = DWord; + + Temp = Data.Bytes[0]; + Data.Bytes[0] = Data.Bytes[3]; + Data.Bytes[3] = Temp; + + Temp = Data.Bytes[1]; + Data.Bytes[1] = Data.Bytes[2]; + Data.Bytes[2] = Temp; + + return Data.DWord; } /** Function to reverse the byte ordering of the individual bytes in a n byte number. diff --git a/LUFA/ManPages/ChangeLog.txt b/LUFA/ManPages/ChangeLog.txt index 593751af1..0a2f43a33 100644 --- a/LUFA/ManPages/ChangeLog.txt +++ b/LUFA/ManPages/ChangeLog.txt @@ -25,6 +25,8 @@ * - Removed unused line encoding data and control requests from the CDC Bootloader code, to save space * - Renamed SERIAL_STREAM_ASSERT() macro to STDOUT_ASSERT() * - The USB_Device_IsRemoteWakeupSent() and USB_Device_IsUSBSuspended() macros have been deleted, as they are now obsolete + * - Rewrote the implementation of the SwapEndian_16() and SwapEndian_32() functions so that they compile down in most instances to + * minimal loads and stores rather than complicated shifts * * <b>Fixed:</b> * - Fixed AVRISP project sending a LOAD EXTENDED ADDRESS command to 128KB AVRs after programming or reading from |