xref: /freebsd/lib/libc/i386/string/strcpy.S (revision af23369a6deaaeb612ab266eb88b8bb8d560c322)
1/*
2 * Copyright (c) 1993 Winning Strategies, Inc.
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 * 3. All advertising materials mentioning features or use of this software
14 *    must display the following acknowledgement:
15 *      This product includes software developed by Winning Strategies, Inc.
16 * 4. The name of the author may not be used to endorse or promote products
17 *    derived from this software without specific prior written permission
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
20 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
21 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
22 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
23 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
24 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
28 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 */
30
31#include <machine/asm.h>
32__FBSDID("$FreeBSD$");
33
34/*
35 * strcpy (dst, src)
36 *	copy the string src to dst.
37 *
38 * Written by:
39 *	J.T. Conklin (jtc@wimsey.com), Winning Strategies, Inc.
40 */
41
42/*
43 * I've unrolled the loop eight times: large enough to make a
44 * significant difference, and small enough not to totally trash the
45 * cache.
46 */
47
48ENTRY(strcpy)
49	movl	4(%esp),%ecx		/* dst address */
50	movl	8(%esp),%edx		/* src address */
51	pushl	%ecx			/* push dst address */
52
53	.align 2,0x90
54L1:	movb	(%edx),%al		/* unroll loop, but not too much */
55	movb	%al,(%ecx)
56	testb	%al,%al
57	je	L2
58	movb	1(%edx),%al
59	movb	%al,1(%ecx)
60	testb	%al,%al
61	je	L2
62	movb	2(%edx),%al
63	movb	%al,2(%ecx)
64	testb	%al,%al
65	je	L2
66	movb	3(%edx),%al
67	movb	%al,3(%ecx)
68	testb	%al,%al
69	je	L2
70	movb	4(%edx),%al
71	movb	%al,4(%ecx)
72	testb	%al,%al
73	je	L2
74	movb	5(%edx),%al
75	movb	%al,5(%ecx)
76	testb	%al,%al
77	je	L2
78	movb	6(%edx),%al
79	movb	%al,6(%ecx)
80	testb	%al,%al
81	je	L2
82	movb	7(%edx),%al
83	movb	%al,7(%ecx)
84	addl	$8,%edx
85	addl	$8,%ecx
86	testb	%al,%al
87	jne	L1
88L2:	popl	%eax			/* pop dst address */
89	ret
90END(strcpy)
91
92	.section .note.GNU-stack,"",%progbits
93