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/*
* Written by J.T. Conklin <jtc@NetBSD.org>.
* Public domain.
*/
#include <machine/asm.h>
#if defined(LIBC_SCCS)
RCSID("$NetBSD: memcmp.S,v 1.3 2014/03/22 19:38:46 jakllsch Exp $")
#endif
ENTRY(memcmp)
pushl %edi
pushl %esi
movl 12(%esp),%edi
movl 16(%esp),%esi
movl 20(%esp),%ecx /* compare by words */
shrl $2,%ecx
repe
cmpsl
jne L5 /* do we match so far? */
movl 20(%esp),%ecx /* compare remainder by bytes */
andl $3,%ecx
repe
cmpsb
jne L6 /* do we match? */
xorl %eax,%eax /* we match, return zero */
popl %esi
popl %edi
ret
L5: movl $4,%ecx /* We know that one of the next */
subl %ecx,%edi /* four pairs of bytes do not */
subl %ecx,%esi /* match. */
repe
cmpsb
L6: xorl %eax,%eax /* Perform unsigned comparison */
movb -1(%edi),%al
xorl %edx,%edx
movb -1(%esi),%dl
subl %edx,%eax
popl %esi
popl %edi
ret
END(memcmp)
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