xref: /openbsd/lib/libc/arch/amd64/string/memmove.S (revision cecf84d4)
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
38	/*
39	 * memmove (dst,src,cnt)
40	 *  ws@tools.de     (Wolfgang Solfrank, TooLs GmbH) +49-228-985800
41	 */
42
43ENTRY(bcopy)
44	xchgq	%rdi,%rsi
45	/* fall into memmove */
46
47ENTRY(memmove)
48	movq	%rdi,%r11	/* save dest */
49	movq	%rdx,%rcx
50	movq	%rdi,%rax
51	subq	%rsi,%rax
52	cmpq	%rcx,%rax	/* overlapping? */
53	jb	1f
54	jmp	2f		/* nope */
55
56// ENTRY(memcpy)
57	movq	%rdi,%r11	/* save dest */
58	movq	%rdx,%rcx
592:
60	cld			/* copy forwards. */
61	shrq	$3,%rcx		/* copy by words */
62	rep
63	movsq
64	movq	%rdx,%rcx
65	andq	$7,%rcx		/* any bytes left? */
66	rep
67	movsb
68	movq	%r11,%rax
69	ret
701:
71	addq	%rcx,%rdi	/* copy backwards. */
72	addq	%rcx,%rsi
73	std
74	andq	$7,%rcx		/* any fractional bytes? */
75	decq	%rdi
76	decq	%rsi
77	rep
78	movsb
79	movq	%rdx,%rcx	/* copy remainder by words */
80	shrq	$3,%rcx
81	subq	$7,%rsi
82	subq	$7,%rdi
83	rep
84	movsq
85	movq	%r11,%rax
86	cld
87	ret
88