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| author | dyson <dyson@FreeBSD.org> | 1996-11-29 07:04:03 +0000 |
|---|---|---|
| committer | dyson <dyson@FreeBSD.org> | 1996-11-29 07:04:03 +0000 |
| commit | 16328d75a712d771d35e60a8c9d8a23663395dab (patch) | |
| tree | 26db12cb7bd59e4a95580c1c0baeff28f2e462aa /sys/i386/include/endian.h | |
| parent | e0557864f9f6cc17ff8cbf0b61b7d32164109170 (diff) | |
| download | FreeBSD-src-16328d75a712d771d35e60a8c9d8a23663395dab.zip FreeBSD-src-16328d75a712d771d35e60a8c9d8a23663395dab.tar.gz | |
Support the appropriate use of bswap instruction on non-I386 builds.
Per Wayne Scott of Intel, the old sequence took 20cycles!!! on a P6.
Another nice side-benefit is that the kernel is about 3K smaller!!!
Submitted by: Wayne Scott <wscott@ichips.intel.com>
Diffstat (limited to 'sys/i386/include/endian.h')
| -rw-r--r-- | sys/i386/include/endian.h | 11 |
1 files changed, 10 insertions, 1 deletions
diff --git a/sys/i386/include/endian.h b/sys/i386/include/endian.h index 85ee057..6e31c7d 100644 --- a/sys/i386/include/endian.h +++ b/sys/i386/include/endian.h @@ -31,7 +31,7 @@ * SUCH DAMAGE. * * from: @(#)endian.h 7.8 (Berkeley) 4/3/91 - * $Id: endian.h,v 1.6 1995/02/12 08:31:31 jkh Exp $ + * $Id: endian.h,v 1.7 1996/10/21 17:15:05 nate Exp $ */ #ifndef _MACHINE_ENDIAN_H_ @@ -64,12 +64,21 @@ : "0" (__X)); \ __X; }) #if __GNUC__ >= 2 +#if defined(KERNEL) && !defined(I386_CPU) +#define __byte_swap_long(x) \ +__extension__ ({ register u_long __X = (x); \ + __asm ("bswap %0" \ + : "=q" (__X) \ + : "0" (__X)); \ + __X; }) +#else #define __byte_swap_long(x) \ __extension__ ({ register u_long __X = (x); \ __asm ("xchgb %h1, %b1\n\trorl $16, %1\n\txchgb %h1, %b1" \ : "=q" (__X) \ : "0" (__X)); \ __X; }) +#endif #define __byte_swap_word(x) \ __extension__ ({ register u_short __X = (x); \ __asm ("xchgb %h1, %b1" \ |
