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 30*84d9c625SLionel Sambuc#include <machine/asm.h> 31*84d9c625SLionel Sambuc 32*84d9c625SLionel SambucRCSID("$NetBSD: strlcat_naive.S,v 1.3 2013/08/22 19:25:00 matt Exp $") 33*84d9c625SLionel Sambuc 34*84d9c625SLionel Sambuc/* LINTSTUB: size_t strlcat(char *, const char *, size_t) */ 35*84d9c625SLionel SambucENTRY(strlcat) 36*84d9c625SLionel Sambuc adds r3, r2, r0 /* point to just end of dst */ 37*84d9c625SLionel Sambuc mov ip, r0 /* need to keep r0 for a while */ 38*84d9c625SLionel Sambuc1: cmp ip, r3 /* still within dst? */ 39*84d9c625SLionel Sambuc beq 3f /* no, get length of src */ 40*84d9c625SLionel Sambuc ldrb r2, [ip], #1 /* load next byte */ 41*84d9c625SLionel Sambuc cmp r2, #0 /* was it a NUL? */ 42*84d9c625SLionel Sambuc bne 1b /* no, get next byte */ 43*84d9c625SLionel Sambuc 44*84d9c625SLionel Sambuc sub r0, ip, r0 /* get actual length of dst */ 45*84d9c625SLionel Sambuc subs r0, r0, #1 /* account for the trailing NUL */ 46*84d9c625SLionel Sambuc subs r3, r3, #1 /* back up to last byte in dst */ 47*84d9c625SLionel Sambuc sub ip, ip, #1 /* back up over the NUL */ 48*84d9c625SLionel Sambuc 49*84d9c625SLionel Sambuc2: ldrb r2, [r1], #1 /* load next byte from append */ 50*84d9c625SLionel Sambuc#if defined(__thumb__) && defined(_ARM_ARCH_T2) 51*84d9c625SLionel Sambuc cbz r2, 5f /* was it a NUL? yes, end of append */ 52*84d9c625SLionel Sambuc#else 53*84d9c625SLionel Sambuc cmp r2, #0 /* was it a NUL? */ 54*84d9c625SLionel Sambuc beq 5f /* yes, end of append */ 55*84d9c625SLionel Sambuc#endif 56*84d9c625SLionel Sambuc adds r0, r0, #1 /* count another byte */ 57*84d9c625SLionel Sambuc cmp ip, r3 /* do we have enough room for it? */ 58*84d9c625SLionel Sambuc#ifdef __thumb__ 59*84d9c625SLionel Sambuc bge 2b 60*84d9c625SLionel Sambuc strb r2, [ip], #1 /* yes, store it */ 61*84d9c625SLionel Sambuc#else 62*84d9c625SLionel Sambuc strblt r2, [ip], #1 /* yes, store it */ 63*84d9c625SLionel Sambuc#endif 64*84d9c625SLionel Sambuc b 2b /* get next byte from append */ 65*84d9c625SLionel Sambuc 66*84d9c625SLionel Sambuc3: subs r0, r3, r0 /* move size to return value */ 67*84d9c625SLionel Sambuc4: ldrb r2, [r1], #1 /* load next byte from append */ 68*84d9c625SLionel Sambuc#if defined(__thumb__) && defined(_ARM_ARCH_T2) 69*84d9c625SLionel Sambuc cbz r2, 6f /* was it a NUL? yes, we're done */ 70*84d9c625SLionel Sambuc#else 71*84d9c625SLionel Sambuc RETc(eq) /* yes, we're done */ 72*84d9c625SLionel Sambuc#endif 73*84d9c625SLionel Sambuc adds r0, r0, #1 /* add one to return value */ 74*84d9c625SLionel Sambuc b 4b /* get next byte from append */ 75*84d9c625SLionel Sambuc 76*84d9c625SLionel Sambuc5: movs r2, #0 /* NUL */ 77*84d9c625SLionel Sambuc strb r2, [ip] /* append final NUL */ 78*84d9c625SLionel Sambuc6: RET /* return */ 79*84d9c625SLionel SambucEND(strlcat) 80