/
strcpy.S
139 lines (131 loc) · 3.14 KB
/
strcpy.S
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
/*
* Copyright (c) 2010 0xlab - http://0xlab.org/
* Copyright (c) 2008 ARM Ltd
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the company may not be used to endorse or promote
* products derived from this software without specific prior written
* permission.
*
* THIS SOFTWARE IS PROVIDED BY ARM LTD ``AS IS'' AND ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL ARM LTD BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
* TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <machine/cpu-features.h>
#define magic1(REG) REG
#define magic2(REG) REG, lsl #7
.text
.global strcpy
.type strcpy, %function
.align 4
strcpy:
.fnstart
PLD(r1, #0)
eor r2, r0, r1
mov ip, r0
tst r2, #3
bne 4f
tst r1, #3
bne 3f
5:
str r5, [sp, #-4]!
mov r5, #0x01
orr r5, r5, r5, lsl #8
orr r5, r5, r5, lsl #16
str r4, [sp, #-4]!
tst r1, #4
ldr r3, [r1], #4
beq 2f
sub r2, r3, magic1(r5)
bics r2, r2, r3
tst r2, magic2(r5)
itt eq
streq r3, [ip], #4
ldreq r3, [r1], #4
bne 1f
/* Inner loop. We now know that r1 is 64-bit aligned, so we
can safely fetch up to two words. This allows us to avoid
load stalls. */
.p2align 2
2:
PLD(r1, #8)
ldr r4, [r1], #4
sub r2, r3, magic1(r5)
bics r2, r2, r3
tst r2, magic2(r5)
sub r2, r4, magic1(r5)
bne 1f
str r3, [ip], #4
bics r2, r2, r4
tst r2, magic2(r5)
itt eq
ldreq r3, [r1], #4
streq r4, [ip], #4
beq 2b
mov r3, r4
1:
#ifdef __ARMEB__
rors r3, r3, #24
#endif
strb r3, [ip], #1
tst r3, #0xff
#ifdef __ARMEL__
ror r3, r3, #8
#endif
bne 1b
ldr r4, [sp], #4
ldr r5, [sp], #4
bx lr
/* Strings have the same offset from word alignment, but it's
not zero. */
3:
tst r1, #1
beq 1f
ldrb r2, [r1], #1
strb r2, [ip], #1
cmp r2, #0
it eq
bxeq lr
1:
tst r1, #2
beq 5b
ldrh r2, [r1], #2
#ifdef __ARMEB__
tst r2, #0xff00
iteet ne
strneh r2, [ip], #2
lsreq r2, r2, #8
streqb r2, [ip]
tstne r2, #0xff
#else
tst r2, #0xff
itet ne
strneh r2, [ip], #2
streqb r2, [ip]
tstne r2, #0xff00
#endif
bne 5b
bx lr
/* src and dst do not have a common word-alignement. Fall back to
byte copying. */
4:
ldrb r2, [r1], #1
strb r2, [ip], #1
cmp r2, #0
bne 4b
bx lr