xref: /freebsd/lib/libc/i386/string/strcat.S (revision b7a1a0a5ff8895e6a5c9404d02357ac9e2eb8091)
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: strcat.S,v 1.1 1993/12/05 13:01:56 ats Exp $
31 */
32
33#if defined(LIBC_RCS) && !defined(lint)
34        .asciz "$Id: strcat.S,v 1.1 1993/12/05 13:01:56 ats Exp $"
35#endif /* LIBC_RCS and not lint */
36
37#include "DEFS.h"
38
39/*
40 * strcat(s, append)
41 *	append a copy of the null-terminated string "append" to the end
42 *	of the null-terminated string s, then add a terminating `\0'.
43 *
44 * Written by:
45 *	J.T. Conklin (jtc@wimsey.com), Winning Strategies, Inc.
46 */
47
48/*
49 * I've unrolled the loop eight times: large enough to make a
50 * significant difference, and small enough not to totally trash the
51 * cashe.
52 */
53
54ENTRY(strcat)
55	pushl	%edi			/* save edi */
56	movl	8(%esp),%edi		/* dst address */
57	movl	12(%esp),%edx		/* src address */
58	pushl	%edi			/* push destination address */
59
60	cld				/* set search forward */
61	xorl	%eax,%eax		/* set search for null terminator */
62	movl	$-1,%ecx		/* set search for lots of characters */
63	repne				/* search! */
64	scasb
65
66	leal	-1(%edi),%ecx		/* correct dst address */
67
68	.align 2,0x90
69L1:	movb	(%edx),%al		/* unroll loop, but not too much */
70	movb	%al,(%ecx)
71	testb	%al,%al
72	je	L2
73	movb	1(%edx),%al
74	movb	%al,1(%ecx)
75	testb	%al,%al
76	je	L2
77	movb	2(%edx),%al
78	movb	%al,2(%ecx)
79	testb	%al,%al
80	je	L2
81	movb	3(%edx),%al
82	movb	%al,3(%ecx)
83	testb	%al,%al
84	je	L2
85	movb	4(%edx),%al
86	movb	%al,4(%ecx)
87	testb	%al,%al
88	je	L2
89	movb	5(%edx),%al
90	movb	%al,5(%ecx)
91	testb	%al,%al
92	je	L2
93	movb	6(%edx),%al
94	movb	%al,6(%ecx)
95	testb	%al,%al
96	je	L2
97	movb	7(%edx),%al
98	movb	%al,7(%ecx)
99	addl	$8,%edx
100	addl	$8,%ecx
101	testb	%al,%al
102	jne	L1
103L2:	popl	%eax			/* pop destination address */
104	popl	%edi			/* restore edi */
105	ret
106