1/*-
2 * Copyright (c) 2013 The NetBSD Foundation, Inc.
3 * All rights reserved.
4 *
5 * This code is derived from software contributed to The NetBSD Foundation
6 * by Matt Thomas of 3am Software Foundry.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
18 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
19 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
20 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
21 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
22 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
23 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
24 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
25 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
26 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
27 * POSSIBILITY OF SUCH DAMAGE.
28 */
29
30#include <machine/asm.h>
31
32RCSID("$NetBSD: strcat_naive.S,v 1.1 2013/01/14 16:36:15 matt Exp $")
33
34/* LINTSTUB: char *strncat(char *, const char *, size_t) */
35ENTRY(strncat)
36	teq	r2, #0			/* count is 0? */
37	RETc(eq)			/*   yes, just return dst */
38	mov	ip, r0			/* need to preserve r0 */
391:	ldrb	r3, [ip], #1		/* load next byte */
40	teq	r3, #0			/* was it a NUL? */
41	bne	1b			/*   no, get next byte */
42	sub	ip, ip, #1		/* back up one to the NUL */
432:	subs	r2, r2, #1		/* subtract 1 from the count */
44	blt	3f			/*   <0? write terminating NUL */
45	ldrb	r3, [r1], #1		/* load next byte from append */
46	strb	r3, [ip], #1		/* store it */
47	teq	r3, #0			/* was it a NUL? */
48	bne	2b			/*   no, get next byte */
49	RET				/* return */
503:	mov	r3, #0			/* load a NUL */
51	strb	r3, [ip]		/* store it */
52	RET				/* return */
53END(strncat)
54