11.1Smatt/*- 21.1Smatt * Copyright (c) 2013 The NetBSD Foundation, Inc. 31.1Smatt * All rights reserved. 41.1Smatt * 51.1Smatt * This code is derived from software contributed to The NetBSD Foundation 61.1Smatt * by Matt Thomas of 3am Software Foundry. 71.1Smatt * 81.1Smatt * Redistribution and use in source and binary forms, with or without 91.1Smatt * modification, are permitted provided that the following conditions 101.1Smatt * are met: 111.1Smatt * 1. Redistributions of source code must retain the above copyright 121.1Smatt * notice, this list of conditions and the following disclaimer. 131.1Smatt * 2. Redistributions in binary form must reproduce the above copyright 141.1Smatt * notice, this list of conditions and the following disclaimer in the 151.1Smatt * documentation and/or other materials provided with the distribution. 161.1Smatt * 171.1Smatt * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 181.1Smatt * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 191.1Smatt * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 201.1Smatt * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 211.1Smatt * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 221.1Smatt * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 231.1Smatt * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 241.1Smatt * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 251.1Smatt * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 261.1Smatt * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 271.1Smatt * POSSIBILITY OF SUCH DAMAGE. 281.1Smatt */ 291.1Smatt 301.1Smatt#include <machine/asm.h> 311.1Smatt 321.1SmattRCSID("$NetBSD: strncat_naive.S,v 1.1 2013/01/23 05:44:52 matt Exp $") 331.1Smatt 341.1Smatt/* LINTSTUB: char *strncat(char *, const char *, size_t) */ 351.1SmattENTRY(strncat) 361.1Smatt teq r2, #0 /* count is 0? */ 371.1Smatt RETc(eq) /* yes, just return dst */ 381.1Smatt mov ip, r0 /* need to preserve r0 */ 391.1Smatt1: ldrb r3, [ip], #1 /* load next byte */ 401.1Smatt teq r3, #0 /* was it a NUL? */ 411.1Smatt bne 1b /* no, get next byte */ 421.1Smatt sub ip, ip, #1 /* back up one to the NUL */ 431.1Smatt2: subs r2, r2, #1 /* subtract 1 from the count */ 441.1Smatt blt 3f /* <0? write terminating NUL */ 451.1Smatt ldrb r3, [r1], #1 /* load next byte from append */ 461.1Smatt strb r3, [ip], #1 /* store it */ 471.1Smatt teq r3, #0 /* was it a NUL? */ 481.1Smatt bne 2b /* no, get next byte */ 491.1Smatt RET /* return */ 501.1Smatt3: mov r3, #0 /* load a NUL */ 511.1Smatt strb r3, [ip] /* store it */ 521.1Smatt RET /* return */ 531.1SmattEND(strncat) 54