xref: /freebsd/lib/libc/i386/string/bcopy.S (revision a3e8fd0b7f663db7eafff527d5c3ca3bcfa8a537)
1/*-
2 * Copyright (c) 1990 The Regents of the University of California.
3 * All rights reserved.
4 *
5 * This code is derived from locore.s.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 * 3. All advertising materials mentioning features or use of this software
16 *    must display the following acknowledgement:
17 *	This product includes software developed by the University of
18 *	California, Berkeley and its contributors.
19 * 4. Neither the name of the University nor the names of its contributors
20 *    may be used to endorse or promote products derived from this software
21 *    without specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * SUCH DAMAGE.
34 */
35
36#include <machine/asm.h>
37__FBSDID("$FreeBSD$");
38
39#if 0
40	RCSID("$NetBSD: bcopy.S,v 1.6 1996/11/12 00:50:06 jtc Exp $")
41#endif
42
43	/*
44	 * (ov)bcopy (src,dst,cnt)
45	 *  ws@tools.de     (Wolfgang Solfrank, TooLs GmbH) +49-228-985800
46	 */
47
48#ifdef MEMCOPY
49ENTRY(memcpy)
50#else
51#ifdef MEMMOVE
52ENTRY(memmove)
53#else
54ENTRY(bcopy)
55#endif
56#endif
57	pushl	%esi
58	pushl	%edi
59#if defined(MEMCOPY) || defined(MEMMOVE)
60	movl	12(%esp),%edi
61	movl	16(%esp),%esi
62	movl	%edi,%eax
63#else
64	movl	12(%esp),%esi
65	movl	16(%esp),%edi
66#endif
67	movl	20(%esp),%ecx
68	movl	%edi,%edx
69	subl	%esi,%edx
70	cmpl	%ecx,%edx	/* overlapping? */
71	jb	1f
72	cld			/* nope, copy forwards. */
73	movl	%ecx,%edx
74	shrl	$2,%ecx		/* copy by words */
75	rep
76	movsl
77	movl	%edx,%ecx
78	andl	$3,%ecx		/* any bytes left? */
79	rep
80	movsb
81	popl	%edi
82	popl	%esi
83	ret
841:
85	addl	%ecx,%edi	/* copy backwards. */
86	addl	%ecx,%esi
87	std
88	movl	%ecx,%edx
89	andl	$3,%ecx		/* any fractional bytes? */
90	decl	%edi
91	decl	%esi
92	rep
93	movsb
94	movl	%edx,%ecx	/* copy remainder by words */
95	shrl	$2,%ecx
96	subl	$3,%esi
97	subl	$3,%edi
98	rep
99	movsl
100	popl	%edi
101	popl	%esi
102	cld
103	ret
104