44 lines
850 B
ArmAsm
44 lines
850 B
ArmAsm
|
/* $OpenBSD: memcmp.S,v 1.4 2005/08/07 11:30:38 espie Exp $ */
|
||
|
|
/*
|
||
|
|
* Written by J.T. Conklin <jtc@netbsd.org>.
|
||
|
|
* Public domain.
|
||
|
|
*/
|
||
|
|
|
||
|
|
#include <machine/asm.h>
|
||
|
|
|
||
|
|
ENTRY(memcmp)
|
||
|
|
pushl %edi
|
||
|
|
pushl %esi
|
||
|
|
movl 12(%esp),%edi
|
||
|
|
movl 16(%esp),%esi
|
||
|
|
cld /* set compare direction forward */
|
||
|
|
|
||
|
|
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: movzbl -1(%edi),%eax /* Perform unsigned comparison */
|
||
|
|
movzbl -1(%esi),%edx
|
||
|
|
subl %edx,%eax
|
||
|
|
popl %esi
|
||
|
|
popl %edi
|
||
|
|
ret
|