1#include <string.h>
2#include <stdint.h>
3
4#ifdef __GNUC__
5typedef __attribute__((__may_alias__)) size_t WT;
6#define WS (sizeof(WT))
7#endif
8
9void *memmove(void *dest, const void *src, size_t n)
10{
11	char *d = dest;
12	const char *s = src;
13
14	if (d==s) return d;
15	if ((uintptr_t)s-(uintptr_t)d-n <= -2*n) return memcpy(d, s, n);
16
17	if (d<s) {
18#ifdef __GNUC__
19		if ((uintptr_t)s % WS == (uintptr_t)d % WS) {
20			while ((uintptr_t)d % WS) {
21				if (!n--) return dest;
22				*d++ = *s++;
23			}
24			for (; n>=WS; n-=WS, d+=WS, s+=WS) *(WT *)d = *(WT *)s;
25		}
26#endif
27		for (; n; n--) *d++ = *s++;
28	} else {
29#ifdef __GNUC__
30		if ((uintptr_t)s % WS == (uintptr_t)d % WS) {
31			while ((uintptr_t)(d+n) % WS) {
32				if (!n--) return dest;
33				d[n] = s[n];
34			}
35			while (n>=WS) n-=WS, *(WT *)(d+n) = *(WT *)(s+n);
36		}
37#endif
38		while (n) n--, d[n] = s[n];
39	}
40
41	return dest;
42}
43