xref: /original-bsd/lib/libc/string/bcopy.c (revision 54e6d6c7)
1 /*
2  * Copyright (c) 1987 Regents of the University of California.
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms are permitted
6  * provided that the above copyright notice and this paragraph are
7  * duplicated in all such forms and that any documentation,
8  * advertising materials, and other materials related to such
9  * distribution and use acknowledge that the software was developed
10  * by the University of California, Berkeley.  The name of the
11  * University may not be used to endorse or promote products derived
12  * from this software without specific prior written permission.
13  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
14  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
15  * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
16  */
17 
18 #if defined(LIBC_SCCS) && !defined(lint)
19 static char sccsid[] = "@(#)bcopy.c	5.4 (Berkeley) 04/01/89";
20 #endif /* LIBC_SCCS and not lint */
21 
22 #include <sys/types.h>
23 
24 /*
25  * bcopy -- vax movc3 instruction
26  */
27 bcopy(src, dst, length)
28 	register long *src, *dst;
29 	register int length;
30 {
31 	if (length && src != dst)
32 		if ((u_int)dst < (u_int)src)
33 			if (((int)src | (int)dst | length) & 3)
34 				do	/* copy by bytes */
35 					*dst++ = *src++;
36 				while (--length);
37 			else {
38 				length >>= 2;
39 				do	/* copy by longs */
40 					*((long *)dst)++ = *((long *)src)++;
41 				while (--length);
42 			}
43 		else {			/* copy backwards */
44 			src += length;
45 			dst += length;
46 			if (((int)src | (int)dst | length) & 3)
47 				do	/* copy by bytes */
48 					*--dst = *--src;
49 				while (--length);
50 			else {
51 				length >>= 2;
52 				do	/* copy by shorts */
53 					*--((long *)dst) = *--((long *)src);
54 				while (--length);
55 			}
56 		}
57 }
58