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freebsd_amp_hwpstate
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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>
This commit is contained in:
John Dyson 1996-11-29 07:04:03 +00:00
parent 4c9f09c0ab
commit f8b4081443
1 changed files with 10 additions and 1 deletions
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11
sys/i386/include/endian.h
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@ -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" \