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
|
/*
* strlen.c -- strlen function. On at least some MIPS chips, a simple
* strlen is faster than the 'optimized' C version.
*
* Copyright (c) 2001, 2002 Red Hat, Inc.
*
* The authors hereby grant permission to use, copy, modify, distribute,
* and license this software and its documentation for any purpose, provided
* that existing copyright notices are retained in all copies and that this
* notice is included verbatim in any distributions. No written agreement,
* license, or royalty fee is required for any of the authorized uses.
* Modifications to this software may be copyrighted by their authors
* and need not follow the licensing terms described here, provided that
* the new terms are clearly indicated on the first page of each file where
* they apply.
*/
#include <stddef.h>
#include <string.h>
/* MIPS16 needs to come first. */
#if defined(__mips16)
size_t
strlen (const char *str)
{
const char *start = str;
while (*str++ != '\0')
;
return str - start - 1;
}
#elif defined(__mips64)
__asm__("" /* 64-bit MIPS targets */
" .set noreorder\n"
" .set nomacro\n"
" .globl strlen\n"
" .ent strlen\n"
"strlen:\n"
" daddiu $2,$4,1\n"
"\n"
"1: lbu $3,0($4)\n"
" bnez $3,1b\n"
" daddiu $4,$4,1\n"
"\n"
" jr $31\n"
" dsubu $2,$4,$2\n"
" .end strlen\n"
" .set macro\n"
" .set reorder\n");
#else
__asm__("" /* 32-bit MIPS targets */
" .set noreorder\n"
" .set nomacro\n"
" .globl strlen\n"
" .ent strlen\n"
"strlen:\n"
" addiu $2,$4,1\n"
"\n"
"1: lbu $3,0($4)\n"
" bnez $3,1b\n"
" addiu $4,$4,1\n"
"\n"
" jr $31\n"
" subu $2,$4,$2\n"
" .end strlen\n"
" .set macro\n"
" .set reorder\n");
#endif
|
