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: strlen_naive.S,v 1.8 2013/08/19 17:02:25 matt Exp $") 32*84d9c625SLionel Sambuc 33*84d9c625SLionel Sambuc#ifdef STRNLEN 34*84d9c625SLionel Sambuc/* LINTSTUB: size_t strnlen(const char *, size_t) */ 35*84d9c625SLionel SambucENTRY(strnlen) 36*84d9c625SLionel Sambuc adds r3, r0, #1 /* start of src + NUL */ 37*84d9c625SLionel Sambuc#ifdef __thumb__ 38*84d9c625SLionel Sambuc adds r2, r0, r1 /* &src[maxlen] */ 39*84d9c625SLionel Sambuc mov ip, r2 40*84d9c625SLionel Sambuc#else 41*84d9c625SLionel Sambuc adds ip, r0, r1 /* &src[maxlen] */ 42*84d9c625SLionel Sambuc#endif 43*84d9c625SLionel Sambuc1: cmp r0, ip /* is this of string? */ 44*84d9c625SLionel Sambuc beq 2f /* yes it is */ 45*84d9c625SLionel Sambuc#ifdef __thumb__ 46*84d9c625SLionel Sambuc ldrb r2, [r0] /* read a byte */ 47*84d9c625SLionel Sambuc adds r0, r0, #1 /* advance to next byte */ 48*84d9c625SLionel Sambuc#else 49*84d9c625SLionel Sambuc ldrb r2, [r0], #1 /* read a byte */ 50*84d9c625SLionel Sambuc#endif 51*84d9c625SLionel Sambuc cmp r2, #0 /* is it a NUL? */ 52*84d9c625SLionel Sambuc bne 1b /* no, get next byte */ 53*84d9c625SLionel Sambuc subs r0, r0, r3 /* get difference between start and end */ 54*84d9c625SLionel Sambuc RET /* return */ 55*84d9c625SLionel Sambuc2: mov r0, r1 /* get maxlen */ 56*84d9c625SLionel Sambuc RET /* return */ 57*84d9c625SLionel SambucEND(strnlen) 58*84d9c625SLionel Sambuc#else /* STRNLEN */ 59*84d9c625SLionel Sambuc/* LINTSTUB: size_t strlen(const char *) */ 60*84d9c625SLionel SambucENTRY(strlen) 61*84d9c625SLionel Sambuc adds r3, r0, #1 /* start of src + NUL */ 62*84d9c625SLionel Sambuc1: 63*84d9c625SLionel Sambuc#ifdef __thumb__ 64*84d9c625SLionel Sambuc ldrb r2, [r0] /* read a byte */ 65*84d9c625SLionel Sambuc adds r0, r0, #1 66*84d9c625SLionel Sambuc#else 67*84d9c625SLionel Sambuc ldrb r2, [r0], #1 /* read a byte */ 68*84d9c625SLionel Sambuc#endif 69*84d9c625SLionel Sambuc cmp r2, #0 /* is it a NUL? */ 70*84d9c625SLionel Sambuc bne 1b /* no, get next byte */ 71*84d9c625SLionel Sambuc subs r0, r0, r3 /* return difference between start and end */ 72*84d9c625SLionel Sambuc RET 73*84d9c625SLionel SambucEND(strlen) 74*84d9c625SLionel Sambuc#endif /* !STRNLEN */ 75