usr/klibc/memmove.c

/*
 * memmove.c
 */

#include <string.h>

void *memmove(void *dst, const void *src, size_t n)
{
	const char *p = src;
	char *q = dst;
#if defined(__i386__) || defined(__x86_64__)
	if (q < p) {
		asm volatile("cld ; rep ; movsb"
			     : "+c" (n), "+S"(p), "+D"(q));
	} else {
		p += (n - 1);
		q += (n - 1);
		asm volatile("std ; rep ; movsb"
			     : "+c" (n), "+S"(p), "+D"(q));
	}
#else
	if (q < p) {
		while (n--) {
			*q++ = *p++;
		}
	} else {
		p += n;
		q += n;
		while (n--) {
			*--q = *--p;
		}
	}
#endif

	return dst;
}
1	/*
2	* memmove.c
3	*/
4
5	#include <string.h>
6
7	void memmove(void dst, const void *src, size_t n)
8	{
9	const char *p = src;
10	char *q = dst;
11	#if defined(__i386__) \|\| defined(__x86_64__)
12	if (q < p) {
13	asm volatile("cld ; rep ; movsb"
14	: "+c" (n), "+S"(p), "+D"(q));
15	} else {
16	p += (n - 1);
17	q += (n - 1);
18	asm volatile("std ; rep ; movsb"
19	: "+c" (n), "+S"(p), "+D"(q));
20	}
21	#else
22	if (q < p) {
23	while (n--) {
24	q++ = p++;
25	}
26	} else {
27	p += n;
28	q += n;
29	while (n--) {
30	--q = --p;
31	}
32	}
33	#endif
34
35	return dst;
36	}