1
0
mirror of https://git.FreeBSD.org/src.git synced 2024-12-13 10:02:38 +00:00

Add machine-specific, optimized implementations of bcmp and memcmp.

PR: 73111
Submitted by: Ville-Pertti Keinonen <will@iki.fi> (taken from NetBSD)
MFC after: 3 weeks
This commit is contained in:
Alan Cox 2005-04-08 05:15:55 +00:00
parent e76ce25370
commit 26f6218be9
Notes: svn2git 2020-12-20 02:59:44 +00:00
svn path=/head/; revision=144782
3 changed files with 67 additions and 1 deletions

View File

@ -1,3 +1,3 @@
# $FreeBSD$
MDSRCS+= bcopy.S bzero.S memcpy.S memmove.S memset.S
MDSRCS+= bcmp.S bcopy.S bzero.S memcmp.S memcpy.S memmove.S memset.S

View File

@ -0,0 +1,25 @@
#include <machine/asm.h>
__FBSDID("$FreeBSD$");
#if 0
RCSID("$NetBSD: bcmp.S,v 1.1 2001/06/19 00:25:04 fvdl Exp $")
#endif
ENTRY(bcmp)
xorl %eax,%eax /* clear return value */
cld /* set compare direction forward */
movq %rdx,%rcx /* compare by words */
shrq $3,%rcx
repe
cmpsq
jne L1
movq %rdx,%rcx /* compare remainder by bytes */
andq $7,%rcx
repe
cmpsb
je L2
L1: incl %eax
L2: ret

View File

@ -0,0 +1,41 @@
/*
* Written by J.T. Conklin <jtc@NetBSD.org>.
* Public domain.
* Adapted for NetBSD/x86_64 by Frank van der Linden <fvdl@wasabisystems.com>
*/
#include <machine/asm.h>
__FBSDID("$FreeBSD$");
#if 0
RCSID("$NetBSD: memcmp.S,v 1.2 2003/07/26 19:24:39 salo Exp $")
#endif
ENTRY(memcmp)
cld /* set compare direction forward */
movq %rdx,%rcx /* compare by longs */
shrq $3,%rcx
repe
cmpsq
jne L5 /* do we match so far? */
movq %rdx,%rcx /* compare remainder by bytes */
andq $7,%rcx
repe
cmpsb
jne L6 /* do we match? */
xorl %eax,%eax /* we match, return zero */
ret
L5: movl $8,%ecx /* We know that one of the next */
subq %rcx,%rdi /* eight pairs of bytes do not */
subq %rcx,%rsi /* match. */
repe
cmpsb
L6: xorl %eax,%eax /* Perform unsigned comparison */
movb -1(%rdi),%al
xorl %edx,%edx
movb -1(%rsi),%dl
subl %edx,%eax
ret