1*84d9c625SLionel Sambuc/*- 2*84d9c625SLionel Sambuc * Copyright (c) 2013 The NetBSD Foundation, Inc. 3*84d9c625SLionel Sambuc * All rights reserved. 4*84d9c625SLionel Sambuc * 5*84d9c625SLionel Sambuc * This code is derived from software contributed to The NetBSD Foundation 6*84d9c625SLionel Sambuc * by Matt Thomas of 3am Software Foundry. 7*84d9c625SLionel Sambuc * 8*84d9c625SLionel Sambuc * Redistribution and use in source and binary forms, with or without 9*84d9c625SLionel Sambuc * modification, are permitted provided that the following conditions 10*84d9c625SLionel Sambuc * are met: 11*84d9c625SLionel Sambuc * 1. Redistributions of source code must retain the above copyright 12*84d9c625SLionel Sambuc * notice, this list of conditions and the following disclaimer. 13*84d9c625SLionel Sambuc * 2. Redistributions in binary form must reproduce the above copyright 14*84d9c625SLionel Sambuc * notice, this list of conditions and the following disclaimer in the 15*84d9c625SLionel Sambuc * documentation and/or other materials provided with the distribution. 16*84d9c625SLionel Sambuc * 17*84d9c625SLionel Sambuc * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 18*84d9c625SLionel Sambuc * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 19*84d9c625SLionel Sambuc * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 20*84d9c625SLionel Sambuc * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 21*84d9c625SLionel Sambuc * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 22*84d9c625SLionel Sambuc * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 23*84d9c625SLionel Sambuc * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 24*84d9c625SLionel Sambuc * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 25*84d9c625SLionel Sambuc * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 26*84d9c625SLionel Sambuc * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 27*84d9c625SLionel Sambuc * POSSIBILITY OF SUCH DAMAGE. 28*84d9c625SLionel Sambuc */ 29*84d9c625SLionel Sambuc#include <machine/asm.h> 30*84d9c625SLionel Sambuc 31*84d9c625SLionel SambucRCSID("$NetBSD: strchr_naive.S,v 1.4 2013/08/19 17:02:25 matt Exp $") 32*84d9c625SLionel Sambuc 33*84d9c625SLionel Sambuc/* LINTSTUB: char * strchr(const char *, int) */ 34*84d9c625SLionel SambucENTRY(strchr) 35*84d9c625SLionel Sambuc#ifdef __thumb__ 36*84d9c625SLionel Sambuc movs r3, #0xff 37*84d9c625SLionel Sambuc ands r1, r1, r3 /* restrict to a byte value */ 38*84d9c625SLionel Sambuc1: ldrb r3, [r0] /* read a byte */ 39*84d9c625SLionel Sambuc cmp r3, r1 /* does it match? */ 40*84d9c625SLionel Sambuc beq 2f /* yes, set return value */ 41*84d9c625SLionel Sambuc adds r0, r0, #1 /* advance to next byte */ 42*84d9c625SLionel Sambuc cmp r3, #0 /* was it a NUL? */ 43*84d9c625SLionel Sambuc bne 1b /* no, get next byte */ 44*84d9c625SLionel Sambuc movs r0, #0 /* set return to NULL */ 45*84d9c625SLionel Sambuc2: RET /* return */ 46*84d9c625SLionel Sambuc#else 47*84d9c625SLionel Sambuc mov r2, r0 /* using r0 as return value */ 48*84d9c625SLionel Sambuc mov r0, #0 /* default to no match */ 49*84d9c625SLionel Sambuc and r1, r1, #0xff /* restrict to a byte value */ 50*84d9c625SLionel Sambuc1: ldrb r3, [r2], #1 /* read a byte */ 51*84d9c625SLionel Sambuc cmp r3, r1 /* does it match? */ 52*84d9c625SLionel Sambuc subeq r0, r2, #1 /* yes, set return value to point to it */ 53*84d9c625SLionel Sambuc cmpne r3, #0 /* no, was it a NUL? */ 54*84d9c625SLionel Sambuc bne 1b /* no, get next byte */ 55*84d9c625SLionel Sambuc RET 56*84d9c625SLionel Sambuc#endif 57*84d9c625SLionel SambucEND(strchr) 58