xref: /freebsd/lib/libc/i386/string/strcpy.S (revision 0c43d89a0d8e976ca494d4837f4c1f3734d2c300)
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 withough 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 *	$Id: strcpy.S,v 1.1 1993/12/05 13:01:58 ats Exp $
31 */
32
33#if defined(LIBC_RCS) && !defined(lint)
34        .asciz "$Id: strcpy.S,v 1.1 1993/12/05 13:01:58 ats Exp $"
35#endif /* LIBC_RCS and not lint */
36
37#include "DEFS.h"
38
39/*
40 * strcpy (dst, src)
41 *	copy the string src to dst.
42 *
43 * Written by:
44 *	J.T. Conklin (jtc@wimsey.com), Winning Strategies, Inc.
45 */
46
47/*
48 * I've unrolled the loop eight times: large enough to make a
49 * significant difference, and small enough not to totally trash the
50 * cashe.
51 */
52
53ENTRY(strcpy)
54	movl	4(%esp),%ecx		/* dst address */
55	movl	8(%esp),%edx		/* src address */
56	pushl	%ecx			/* push dst address */
57
58	.align 2,0x90
59L1:	movb	(%edx),%al		/* unroll loop, but not too much */
60	movb	%al,(%ecx)
61	testb	%al,%al
62	je	L2
63	movb	1(%edx),%al
64	movb	%al,1(%ecx)
65	testb	%al,%al
66	je	L2
67	movb	2(%edx),%al
68	movb	%al,2(%ecx)
69	testb	%al,%al
70	je	L2
71	movb	3(%edx),%al
72	movb	%al,3(%ecx)
73	testb	%al,%al
74	je	L2
75	movb	4(%edx),%al
76	movb	%al,4(%ecx)
77	testb	%al,%al
78	je	L2
79	movb	5(%edx),%al
80	movb	%al,5(%ecx)
81	testb	%al,%al
82	je	L2
83	movb	6(%edx),%al
84	movb	%al,6(%ecx)
85	testb	%al,%al
86	je	L2
87	movb	7(%edx),%al
88	movb	%al,7(%ecx)
89	addl	$8,%edx
90	addl	$8,%ecx
91	testb	%al,%al
92	jne	L1
93L2:	popl	%eax			/* pop dst address */
94	ret
95