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
|
#include <stdint.h>
#include <string.h>
/*
* Profilable substitutes for mem*(), lacking libc_p.a
*
* This code was written with reference to newlib, but does not copy every
* quirk and loop-unrolling optimization from newlib. Its only purpose is
* to let us figure out who is calling memcpy 2 million times.
*/
#define is_word_aligned(x) (((size_t)(x) & 3) == 0)
void *memcpy(void *dst, const void *src, size_t n)
{
uint8_t *d8 = (uint8_t *)dst;
uint8_t *s8 = (uint8_t *)src;
if (n >= 4 && is_word_aligned(src) && is_word_aligned(dst)) {
uint32_t *d32 = (uint32_t *)dst;
uint32_t *s32 = (uint32_t *)src;
while (n >= 4) {
*d32++ = *s32++;
n -= 4;
}
d8 = (uint8_t *)d32;
s8 = (uint8_t *)s32;
}
while (n-- > 0) {
*d8++ = *s8++;
}
return dst;
}
void *memset(void *dst, int c, size_t n)
{
uint8_t *d8 = (uint8_t *)dst;
uint8_t c8 = (uint8_t)c;
if (n >= 4 && is_word_aligned(dst)) {
uint32_t *d32 = (uint32_t *)dst;
uint32_t c32 = (c8 << 24) | (c8 << 16) | (c8 << 8) | (c8);
while (n >= 4) {
*d32++ = c32;
n -= 4;
}
d8 = (uint8_t *)d32;
}
while (n-- > 0) {
*d8++ = c8;
}
return dst;
}
int memcmp(const void *dst, const void *src, size_t n)
{
uint8_t *d8 = (uint8_t *)dst;
uint8_t *s8 = (uint8_t *)src;
if (n >= 4 && is_word_aligned(src) && is_word_aligned(dst)) {
uint32_t *d32 = (uint32_t *)dst;
uint32_t *s32 = (uint32_t *)src;
while (n >= 4) {
if (*d32 != *s32)
break;
d32++;
s32++;
n -= 4;
}
d8 = (uint8_t *)d32;
s8 = (uint8_t *)s32;
}
while (n-- > 0) {
if (*d8 != *s8)
return (*d8 - *s8);
d8++;
s8++;
}
return 0;
}
void *memmove(void *dst, const void *src, size_t n)
{
uint8_t *d8 = (uint8_t *)dst;
uint8_t *s8 = (uint8_t *)src;
if ((s8 < d8) && (d8 < s8 + n)) {
/* Destructive overlap...have to copy backwards */
s8 += n;
d8 += n;
while (n-- > 0) {
*--d8 = *--s8;
}
return dst;
}
return memcpy(dst, src, n);
}
|
