xref: /csrg-svn/lib/libc/tahoe/string/bcopy.s (revision 34438)
1/*
2 * Copyright (c) 1988 Regents of the University of California.
3 * All rights reserved.
4 *
5 * This code is derived from software contributed to Berkeley by
6 * Computer Consoles Inc.
7 *
8 * Redistribution and use in source and binary forms are permitted
9 * provided that this notice is preserved and that due credit is given
10 * to the University of California at Berkeley. The name of the University
11 * may not be used to endorse or promote products derived from this
12 * software without specific prior written permission. This software
13 * is provided ``as is'' without express or implied warranty.
14 */
15
16#if defined(LIBC_SCCS) && !defined(lint)
17_sccsid:.asciz	"@(#)bcopy.s	1.2 (Berkeley) 05/23/88"
18#endif /* LIBC_SCCS and not lint */
19
20/* bcopy(from, to, size) */
21#include "DEFS.h"
22
23ENTRY(bcopy, 0)
24	movl	4(fp),r0
25	movl	8(fp),r1
26	movl	12(fp),r2
27	cmpl	r0,r1
28	bgtru	1f		# normal forward case
29	beql	2f		# equal, nothing to do
30	addl2	r2,r0		# may be overlapping
31	cmpl	r0,r1
32	bgtru	3f
33	subl2	r2,r0		# normal forward case
341:
35	movblk
362:
37	ret
383:
39	addl2	r2,r1		# overlapping, must do backwards
40	subl3	r0,r1,r3
41	movl	r2,r4
42	jbr	5f
434:
44	subl2	r3,r0
45	subl2	r3,r1
46	movl	r3,r2
47	movblk
48	subl2	r3,r0
49	subl2	r3,r1
50	subl2	r3,r4
515:
52	cmpl	r4,r3
53	jgtr	4b
54	movl	r4,r2
55	subl2	r2,r0
56	subl2	r2,r1
57	movblk
58	ret
59