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/*
* ====================================================
* Copyright (C) 1998, 2002 by Red Hat Inc. All rights reserved.
*
* Permission to use, copy, modify, and distribute this
* software is freely granted, provided that this notice
* is preserved.
* ====================================================
*/
#include "i386mach.h"
.global SYM (memcmp)
SOTYPE_FUNCTION(memcmp)
SYM (memcmp):
pushl ebp
movl esp,ebp
subl $16,esp
pushl ebx
pushl edi
pushl esi
movl 8(ebp),edi
movl 12(ebp),esi
movl 16(ebp),ecx
cld
/* check if length is zero in which case just return 0 */
xorl eax,eax
testl ecx,ecx
jz L4
#ifndef __OPTIMIZE_SIZE__
/* if aligned on long boundary, compare doublewords at a time first */
movl edi,eax
orl esi,eax
testb $3,al
jne BYTECMP
movl ecx,ebx
shrl $2,ecx /* calculate number of long words to compare */
repz
cmpsl
jz L5
subl $4,esi
subl $4,edi
movl $4,ecx
jmp BYTECMP
L5:
andl $3,ebx /* calculate number of remaining bytes */
movl ebx,ecx
#endif /* not __OPTIMIZE_SIZE__ */
BYTECMP: /* compare any unaligned bytes or remainder bytes */
repz
cmpsb
/* set output to be < 0 if less than, 0 if equal, or > 0 if greater than */
L3:
xorl edx,edx
movb -1(esi),dl
xorl eax,eax
movb -1(edi),al
subl edx,eax
L4:
leal -28(ebp),esp
popl esi
popl edi
popl ebx
leave
ret
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