/*- * 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: strcat_naive.S,v 1.3 2013/08/19 17:02:25 matt Exp $") ENTRY(strcat) mov ip, r0 /* need to preserve r0 */ #if defined(__thumb__) 1: ldrb r2, [r0] /* load next byte */ adds r0, r0, #1 /* advance */ cmp r2, #0 /* was it a NUL? */ bne 1b /* no, get next byte */ subs r0, r0, #1 /* back up one to the NUL */ subs r1, r1, r0 /* save one increment */ 2: ldrb r2, [r1, r0] /* load next byte from append */ strb r2, [r0] /* store it */ adds r0, r0, #1 /* advance */ cmp r2, #0 /* was it a NUL? */ bne 2b /* no, get next byte */ mov r0, ip /* restore dst address */ RET /* return */ #else /* !__thumb__ */ mov ip, r0 /* need to preserve r0 */ 1: ldrb r2, [ip], #1 /* load next byte */ teq r2, #0 /* was it a NUL? */ bne 1b /* no, get next byte */ sub ip, ip, #1 /* back up one to the NUL */ 2: ldrb r2, [r1], #1 /* load next byte from append */ strb r2, [ip], #1 /* store it */ teq r2, #0 /* was it a NUL? */ bne 2b /* no, get next byte */ RET /* return */ #endif END(strcat) |