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 1.3 2013/08/19 17:02:25 matt Exp $")
33
34ENTRY(strcat)
35          mov       ip, r0                        /* need to preserve r0 */
36#if defined(__thumb__)
371:        ldrb      r2, [r0]            /* load next byte */
38          adds      r0, r0, #1                    /* advance */
39          cmp       r2, #0                        /* was it a NUL? */
40          bne       1b                            /*   no, get next byte */
41          subs      r0, r0, #1                    /* back up one to the NUL */
42          subs      r1, r1, r0                    /* save one increment */
432:        ldrb      r2, [r1, r0]                  /* load next byte from append */
44          strb      r2, [r0]            /* store it */
45          adds      r0, r0, #1                    /* advance */
46          cmp       r2, #0                        /* was it a NUL? */
47          bne       2b                            /*   no, get next byte */
48          mov       r0, ip                        /* restore dst address */
49          RET                                     /* return */
50#else /* !__thumb__ */
51          mov       ip, r0                        /* need to preserve r0 */
521:        ldrb      r2, [ip], #1                  /* load next byte */
53          teq       r2, #0                        /* was it a NUL? */
54          bne       1b                            /*   no, get next byte */
55          sub       ip, ip, #1                    /* back up one to the NUL */
562:        ldrb      r2, [r1], #1                  /* load next byte from append */
57          strb      r2, [ip], #1                  /* store it */
58          teq       r2, #0                        /* was it a NUL? */
59          bne       2b                            /*   no, get next byte */
60          RET                                     /* return */
61#endif
62END(strcat)
63