xref: /original-bsd/lib/libc/tahoe/string/bcopy.s (revision c3e32dec)
1/*
2 * Copyright (c) 1988, 1993
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * %sccs.include.redist.c%
6 *
7 * This code is derived from software contributed to Berkeley by
8 * Computer Consoles Inc.
9 */
10
11#if defined(LIBC_SCCS) && !defined(lint)
12	.asciz "@(#)bcopy.s	8.1 (Berkeley) 06/04/93"
13#endif /* LIBC_SCCS and not lint */
14
15/* bcopy(from, to, size) */
16#include "DEFS.h"
17
18ENTRY(bcopy, 0)
19	movl	4(fp),r0
20	movl	8(fp),r1
21	movl	12(fp),r2
22	cmpl	r0,r1
23	bgtru	1f		# normal forward case
24	beql	2f		# equal, nothing to do
25	addl2	r2,r0		# may be overlapping
26	cmpl	r0,r1
27	bgtru	3f
28	subl2	r2,r0		# normal forward case
291:
30	movblk
312:
32	ret
333:
34	addl2	r2,r1		# overlapping, must do backwards
35	subl3	r0,r1,r3
36	movl	r2,r4
37	jbr	5f
384:
39	subl2	r3,r0
40	subl2	r3,r1
41	movl	r3,r2
42	movblk
43	subl2	r3,r0
44	subl2	r3,r1
45	subl2	r3,r4
465:
47	cmpl	r4,r3
48	jgtr	4b
49	movl	r4,r2
50	subl2	r2,r0
51	subl2	r2,r1
52	movblk
53	ret
54