xref: /netbsd-src/lib/libc/arch/i386/string/bcopy.S (revision 23c8222edbfb0f0932d88a8351d3a0cf817dfb9e)
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. Neither the name of the University nor the names of its contributors
16 *    may be used to endorse or promote products derived from this software
17 *    without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32#include <machine/asm.h>
33
34#if defined(LIBC_SCCS)
35	RCSID("$NetBSD: bcopy.S,v 1.12 2003/08/07 16:42:08 agc Exp $")
36#endif
37
38	/*
39	 * (ov)bcopy (src,dst,cnt)
40	 *  ws@tools.de     (Wolfgang Solfrank, TooLs GmbH) +49-228-985800
41	 */
42
43#ifdef MEMCOPY
44ENTRY(memcpy)
45#else
46#ifdef MEMMOVE
47ENTRY(memmove)
48#else
49ENTRY(bcopy)
50#endif
51#endif
52	pushl	%esi
53	pushl	%edi
54#if defined(MEMCOPY) || defined(MEMMOVE)
55	movl	12(%esp),%edi
56	movl	16(%esp),%esi
57	movl	%edi,%eax	/* return value */
58#else
59	movl	12(%esp),%esi
60	movl	16(%esp),%edi
61#endif
62	movl	20(%esp),%ecx
63#if defined(MEMCOPY)
64	movl	%ecx,%edx
65#else
66	movl	%edi,%edx
67	subl	%esi,%edx
68	cmpl	%ecx,%edx	/* overlapping? */
69	movl	%ecx,%edx
70	jb	1f
71#endif
72	cld			/* nope, copy forwards. */
73	shrl	$2,%ecx		/* copy by words */
74	rep
75	movsl
76	movl	%edx,%ecx
77	andl	$3,%ecx		/* any bytes left? */
78	rep
79	movsb
80	popl	%edi
81	popl	%esi
82	ret
831:
84	addl	%ecx,%edi	/* copy backwards. */
85	addl	%ecx,%esi
86	std
87	andl	$3,%ecx		/* any fractional bytes? */
88	decl	%edi
89	decl	%esi
90	rep
91	movsb
92	movl	%edx,%ecx	/* copy remainder by words */
93	shrl	$2,%ecx
94	subl	$3,%esi
95	subl	$3,%edi
96	rep
97	movsl
98	popl	%edi
99	popl	%esi
100	cld
101	ret
102