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
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
|
/*
* ====================================================
* Copyright (C) 1998 by Cygnus Solutions. 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 (memmove)
SYM (memmove):
pushl ebp
movl esp,ebp
pushl esi
pushl edi
pushl ebx
movl 8(ebp),edi
movl 16(ebp),ecx
movl 12(ebp),esi
/* check for destructive overlap (src < dst && dst < src + length) */
cld
cmpl edi,esi
jae .L2
leal -1(ecx,esi),ebx
cmpl ebx,edi
ja .L2
/* IF: destructive overlap, must copy backwards */
addl ecx,esi
addl ecx,edi
std
#ifndef __OPTIMIZE_SIZE__
cmpl $8,ecx
jbe .L13
.L18:
/* move trailing bytes in reverse until destination address is long word aligned */
movl edi,edx
movl ecx,ebx
andl $3,edx
jz .L21
movl edx,ecx
decl esi
decl edi
subl ecx,ebx
rep
movsb
mov ebx,ecx
incl esi
incl edi
.L21:
/* move bytes in reverse, a long word at a time */
shrl $2,ecx
subl $4,esi
subl $4,edi
rep
movsl
addl $4,esi
addl $4,edi
movl ebx,ecx
andl $3,ecx
#endif /* !__OPTIMIZE_SIZE__ */
/* handle any remaining bytes not on a long word boundary */
.L13:
decl esi
decl edi
.L15:
rep
movsb
jmp .L5
.p2align 4,,7
/* ELSE: no destructive overlap so we copy forwards */
.L2:
#ifndef __OPTIMIZE_SIZE__
cmpl $8,ecx
jbe .L3
/* move any preceding bytes until destination address is long word aligned */
movl edi,edx
movl ecx,ebx
andl $3,edx
jz .L11
movl $4,ecx
subl edx,ecx
andl $3,ecx
subl ecx,ebx
rep
movsb
mov ebx,ecx
/* move bytes a long word at a time */
.L11:
shrl $2,ecx
.p2align 2
rep
movsl
movl ebx,ecx
andl $3,ecx
#endif /* !__OPTIMIZE_SIZE__ */
/* handle any remaining bytes */
.L3:
rep
movsb
.L5:
movl 8(ebp),eax
cld
leal -12(ebp),esp
popl ebx
popl edi
popl esi
leave
ret
|
