1 /*
2 * memcpy.c
3 */
4
5 #include <string.h>
6 #include <stdint.h>
7
memcpy(void * dst,const void * src,size_t n)8 void *memcpy(void *dst, const void *src, size_t n)
9 {
10 const char *p = src;
11 char *q = dst;
12 #if defined(__i386__)
13 size_t nl = n >> 2;
14 asm volatile ("cld ; rep ; movsl ; movl %3,%0 ; rep ; movsb":"+c" (nl),
15 "+S"(p), "+D"(q)
16 :"r"(n & 3));
17 #elif defined(__x86_64__)
18 size_t nq = n >> 3;
19 asm volatile ("cld ; rep ; movsq ; movl %3,%%ecx ; rep ; movsb":"+c"
20 (nq), "+S"(p), "+D"(q)
21 :"r"((uint32_t) (n & 7)));
22 #else
23 while (n--) {
24 *q++ = *p++;
25 }
26 #endif
27
28 return dst;
29 }
30