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
|
/*
* Copyright (C) 2016 Andes Technology, Inc.
* Licensed under the LGPL v2.1, see the file COPYING.LIB in this tarball.
*/
/* Copyright (C) 1998, 2003 Free Software Foundation, Inc.
* 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, write to the Free
* Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
* 02111-1307 USA.
*/
#include <features.h>
#include <sysdep.h>
!==========================================================
! void *memset(void *dst, int val, int len);
!
! dst: $r0
! val: $r1
! len: $r2
! ret: $r0 - pointer to the memory area dst.
!==========================================================
.weak memset
ENTRY(memset)
move $r5, $r0 ! Return value
beqz $r2, .Lend_memset ! Exit when len = 0
srli $r3, $r2, 2 ! r3 is how many words to copy
andi $r2, $r2, 3 ! How many bytes are less than a word
beqz $r3, .Lbyte_set ! When n is less than a word
! set r1 from to abababab
andi $r1, $r1, 0x00ff ! r1 = 000000ab
slli $r4, $r1, 8 ! r4 = 0000ab00
or $r1, $r1, $r4 ! r1 = 0000abab
slli $r4, $r1, 16 ! r4 = abab0000
or $r1, $r1, $r4 ! r1 = abababab
.Lword_set:
addi $r3, $r3, -1 ! How many words left to copy
smw.bim $r1, [$r5], $r1 ! Copy the word to det
bnez $r3, .Lword_set ! Still words to set, continue looping
beqz $r2, .Lend_memset ! No left byte to set
.Lbyte_set:
! Less than 4 bytes left to set
addi $r2, $r2, -1 ! Decrease len by 1
sbi.p $r1, [$r5], 1 ! Set data of the next byte to r1
bnez $r2, .Lbyte_set ! Still bytes left to set
.Lend_memset:
ret
END(memset)
libc_hidden_def(memset)
|
