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
|
/* Copyright (C) 1998-2021 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Philip Blundell <philb@gnu.org>
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library. If not, see
<https://www.gnu.org/licenses/>. */
/* Thumb requires excessive IT insns here. */
#define NO_THUMB
#include <sysdep.h>
.text
.syntax unified
/* void *memset (dstpp, c, len) */
ENTRY(memset)
mov r3, r0
cmp r2, #8
bcc 2f @ less than 8 bytes to move
1:
tst r3, #3 @ aligned yet?
strbne r1, [r3], #1
subne r2, r2, #1
bne 1b
and r1, r1, #255 @ clear any sign bits
orr r1, r1, r1, lsl $8
orr r1, r1, r1, lsl $16
mov ip, r1
1:
subs r2, r2, #8
stmiacs r3!, {r1, ip} @ store up to 32 bytes per loop iteration
subscs r2, r2, #8
stmiacs r3!, {r1, ip}
subscs r2, r2, #8
stmiacs r3!, {r1, ip}
subscs r2, r2, #8
stmiacs r3!, {r1, ip}
bcs 1b
and r2, r2, #7
2:
subs r2, r2, #1 @ store up to 4 bytes per loop iteration
strbcs r1, [r3], #1
subscs r2, r2, #1
strbcs r1, [r3], #1
subscs r2, r2, #1
strbcs r1, [r3], #1
subscs r2, r2, #1
strbcs r1, [r3], #1
bcs 2b
DO_RET(lr)
END(memset)
libc_hidden_builtin_def (memset)
|
