1 /*
2 ** Copyright 2001, Travis Geiselbrecht. All rights reserved.
3 ** Distributed under the terms of the NewOS License.
4 */
5 /*
6  * Copyright (c) 2008 Travis Geiselbrecht
7  *
8  * Use of this source code is governed by a MIT-style
9  * license that can be found in the LICENSE file or at
10  * https://opensource.org/licenses/MIT
11  */
12 #include <string.h>
13 #include <sys/types.h>
14 
15 
16 #if !_ASM_MEMCPY
17 
18 typedef long word;
19 
20 #define lsize sizeof(word)
21 #define lmask (lsize - 1)
22 
memcpy(void * dest,const void * src,size_t count)23 void *memcpy(void *dest, const void *src, size_t count) {
24     char *d = (char *)dest;
25     const char *s = (const char *)src;
26     int len;
27 
28     if (count == 0 || dest == src)
29         return dest;
30 
31     if (((long)d | (long)s) & lmask) {
32         // src and/or dest do not align on word boundary
33         if ((((long)d ^ (long)s) & lmask) || (count < lsize))
34             len = count; // copy the rest of the buffer with the byte mover
35         else
36             len = lsize - ((long)d & lmask); // move the ptrs up to a word boundary
37 
38         count -= len;
39         for (; len > 0; len--)
40             *d++ = *s++;
41     }
42     for (len = count / lsize; len > 0; len--) {
43         *(word *)d = *(word *)s;
44         d += lsize;
45         s += lsize;
46     }
47     for (len = count & lmask; len > 0; len--)
48         *d++ = *s++;
49 
50     return dest;
51 }
52 
53 #endif
54