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
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
|
/* $OpenBSD: strcat.S,v 1.2 1996/09/27 06:47:49 mickey Exp $ */
/*
* Written by J.T. Conklin <jtc@netbsd.org>.
* Public domain.
*/
#include <machine/asm.h>
/*
* NOTE: I've unrolled the loop eight times: large enough to make a
* significant difference, and small enough not to totally trash the
* cache.
*/
ENTRY(strcat)
pushl %edi /* save edi */
movl 8(%esp),%edi /* dst address */
movl 12(%esp),%edx /* src address */
pushl %edi /* push destination address */
cld /* set search forward */
xorl %eax,%eax /* set search for null terminator */
movl $-1,%ecx /* set search for lots of characters */
repne /* search! */
scasb
leal -1(%edi),%ecx /* correct dst address */
.align 2,0x90
L1: movb (%edx),%al /* unroll loop, but not too much */
movb %al,(%ecx)
testb %al,%al
jz L2
movb 1(%edx),%al
movb %al,1(%ecx)
testb %al,%al
jz L2
movb 2(%edx),%al
movb %al,2(%ecx)
testb %al,%al
jz L2
movb 3(%edx),%al
movb %al,3(%ecx)
testb %al,%al
jz L2
movb 4(%edx),%al
movb %al,4(%ecx)
testb %al,%al
jz L2
movb 5(%edx),%al
movb %al,5(%ecx)
testb %al,%al
jz L2
movb 6(%edx),%al
movb %al,6(%ecx)
testb %al,%al
jz L2
movb 7(%edx),%al
movb %al,7(%ecx)
addl $8,%edx
addl $8,%ecx
testb %al,%al
jnz L1
L2: popl %eax /* pop destination address */
popl %edi /* restore edi */
ret
|
