/*- * 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: strchr_naive.S,v 1.4 2013/08/19 17:02:25 matt Exp $") /* LINTSTUB: char * strchr(const char *, int) */ ENTRY(strchr) #ifdef __thumb__ movs r3, #0xff ands r1, r1, r3 /* restrict to a byte value */ 1: ldrb r3, [r0] /* read a byte */ cmp r3, r1 /* does it match? */ beq 2f /* yes, set return value */ adds r0, r0, #1 /* advance to next byte */ cmp r3, #0 /* was it a NUL? */ bne 1b /* no, get next byte */ movs r0, #0 /* set return to NULL */ 2: RET /* return */ #else mov r2, r0 /* using r0 as return value */ mov r0, #0 /* default to no match */ and r1, r1, #0xff /* restrict to a byte value */ 1: ldrb r3, [r2], #1 /* read a byte */ cmp r3, r1 /* does it match? */ subeq r0, r2, #1 /* yes, set return value to point to it */ cmpne r3, #0 /* no, was it a NUL? */ bne 1b /* no, get next byte */ RET #endif END(strchr) |