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
|
/*
* memcpy.c
*/
#include <string.h>
#include <stdint.h>
void *memcpy(void *dst, const void *src, size_t n)
{
const char *p = src;
char *q = dst;
#if defined(__i386__)
size_t nl = n >> 2;
asm volatile ("cld ; rep ; movsl ; movl %3,%0 ; rep ; movsb":"+c" (nl),
"+S"(p), "+D"(q)
:"r"(n & 3));
#elif defined(__x86_64__)
size_t nq = n >> 3;
asm volatile ("cld ; rep ; movsq ; movl %3,%%ecx ; rep ; movsb":"+c"
(nq), "+S"(p), "+D"(q)
:"r"((uint32_t) (n & 7)));
#else
while (n--) {
*q++ = *p++;
}
#endif
return dst;
}
|
