/*- * Copyright (c) 2013 The NetBSD Foundation, Inc. * All rights reserved. * * This code is derived from software contributed to The NetBSD Foundation * by Matt Thomas of 3am Software Foundry. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. */ #include <machine/asm.h> RCSID("$NetBSD: strncat_naive.S,v 1.1 2013/01/23 05:44:52 matt Exp $") /* LINTSTUB: char *strncat(char *, const char *, size_t) */ ENTRY(strncat) teq r2, #0 /* count is 0? */ RETc(eq) /* yes, just return dst */ mov ip, r0 /* need to preserve r0 */ 1: ldrb r3, [ip], #1 /* load next byte */ teq r3, #0 /* was it a NUL? */ bne 1b /* no, get next byte */ sub ip, ip, #1 /* back up one to the NUL */ 2: subs r2, r2, #1 /* subtract 1 from the count */ blt 3f /* <0? write terminating NUL */ ldrb r3, [r1], #1 /* load next byte from append */ strb r3, [ip], #1 /* store it */ teq r3, #0 /* was it a NUL? */ bne 2b /* no, get next byte */ RET /* return */ 3: mov r3, #0 /* load a NUL */ strb r3, [ip] /* store it */ RET /* return */ END(strncat) |