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