1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
|
/*
* 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>
ENTRY(memcmp)
RETGUARD_SETUP(memcmp, r11)
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 */
jmp L7
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
L7: RETGUARD_CHECK(memcmp, r11)
ret
|
