1/*
2** Copyright 2001, Travis Geiselbrecht. All rights reserved.
3** Distributed under the terms of the NewOS License.
4*/
5
6#include <sys/types.h>
7#include <string.h>
8
9
10typedef int word;
11
12#define lsize sizeof(word)
13#define lmask (lsize - 1)
14
15void *memcpy(void *dest, const void *src, size_t count)
16{
17	char *d = (char *)dest;
18	const char *s = (const char *)src;
19	int len;
20
21	if(count == 0 || dest == src)
22		return dest;
23
24	if(((long)d | (long)s) & lmask) {
25		// src and/or dest do not align on word boundary
26		if((((long)d ^ (long)s) & lmask) || (count < lsize))
27			len = count; // copy the rest of the buffer with the byte mover
28		else
29			len = lsize - ((long)d & lmask); // move the ptrs up to a word boundary
30
31		count -= len;
32		for(; len > 0; len--)
33			*d++ = *s++;
34	}
35	for(len = count / lsize; len > 0; len--) {
36		*(word *)d = *(word *)s;
37		d += lsize;
38		s += lsize;
39	}
40	for(len = count & lmask; len > 0; len--)
41		*d++ = *s++;
42
43	return dest;
44}
45
46