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
|
/*
Copyright (c) 2013, Raspberry Pi Foundation
Copyright (c) 2013, RISC OS Open 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:
* Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
* 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.
* Neither the name of the copyright holder nor the
names of its contributors may be used to endorse or promote products
derived from this software without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "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 THE COPYRIGHT HOLDER OR CONTRIBUTORS 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 <linux/linkage.h>
#include "arm-mem.h"
/* Prevent the stack from becoming executable */
#if defined(__linux__) && defined(__ELF__)
.section .note.GNU-stack,"",%progbits
#endif
.text
.arch armv6
.object_arch armv4
.arm
.altmacro
.p2align 2
/*
* void *memset(void *s, int c, size_t n);
* On entry:
* a1 = pointer to buffer to fill
* a2 = byte pattern to fill with (caller-narrowed)
* a3 = number of bytes to fill
* On exit:
* a1 preserved
*/
ENTRY(mmioset)
ENTRY(memset)
ENTRY(__memset32)
ENTRY(__memset64)
S .req a1
DAT0 .req a2
N .req a3
DAT1 .req a4
DAT2 .req ip
DAT3 .req lr
orr DAT0, DAT0, DAT0, lsl #8
push {S, lr}
orr DAT0, DAT0, DAT0, lsl #16
mov DAT1, DAT0
/* See if we're guaranteed to have at least one 16-byte aligned 16-byte write */
cmp N, #31
blo 170f
161: sub N, N, #16 /* simplifies inner loop termination */
/* Leading words and bytes */
tst S, #15
beq 164f
rsb DAT3, S, #0 /* bits 0-3 = number of leading bytes until aligned */
movs DAT2, DAT3, lsl #31
submi N, N, #1
strmib DAT0, [S], #1
subcs N, N, #2
strcsh DAT0, [S], #2
movs DAT2, DAT3, lsl #29
submi N, N, #4
strmi DAT0, [S], #4
subcs N, N, #8
stmcsia S!, {DAT0, DAT1}
164: /* Delayed set up of DAT2 and DAT3 so we could use them as scratch registers above */
mov DAT2, DAT0
mov DAT3, DAT0
/* Now the inner loop of 16-byte stores */
165: stmia S!, {DAT0, DAT1, DAT2, DAT3}
subs N, N, #16
bhs 165b
166: /* Trailing words and bytes */
movs N, N, lsl #29
stmcsia S!, {DAT0, DAT1}
strmi DAT0, [S], #4
movs N, N, lsl #2
strcsh DAT0, [S], #2
strmib DAT0, [S]
199: pop {S, pc}
170: /* Short case */
mov DAT2, DAT0
mov DAT3, DAT0
tst S, #3
beq 174f
172: subs N, N, #1
blo 199b
strb DAT0, [S], #1
tst S, #3
bne 172b
174: tst N, #16
stmneia S!, {DAT0, DAT1, DAT2, DAT3}
b 166b
.unreq S
.unreq DAT0
.unreq N
.unreq DAT1
.unreq DAT2
.unreq DAT3
ENDPROC(__memset64)
ENDPROC(__memset32)
ENDPROC(memset)
ENDPROC(mmioset)
|
