strcpy_thumb.S revision 1.2
1/*- 2 * Copyright (c) 2013 The NetBSD Foundation, Inc. 3 * All rights reserved. 4 * 5 * This code is derived from software contributed to The NetBSD Foundation 6 * by Matt Thomas of 3am Software Foundry. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 18 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 19 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 20 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 21 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 22 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 23 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 24 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 25 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 26 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 27 * POSSIBILITY OF SUCH DAMAGE. 28 */ 29#include <machine/asm.h> 30 31RCSID("$NetBSD: strcpy_thumb.S,v 1.2 2017/01/13 13:14:54 christos Exp $") 32 33#ifdef _LIBC 34#ifdef STRLCPY 35WEAK_ALIAS(strlcpy, _strlcpy) 36#endif 37#endif 38 39/* 40 * These are "naive" versions of the str*cpy routines designed to be simple 41 * and small. 42 */ 43 44#if defined(STRLCPY) 45/* LINTSTUB: size_t strlcpy(char *, const char *, size_t) */ 46ENTRY(_strlcpy) 47 adds r3, r1, #1 /* save src pointer (+ NUL) */ 48 subs r2, r2, #1 /* make sure there's room for a NUL */ 49 blt 3f /* no room, do the strlen */ 50 adds r2, r2, r0 /* get end of dst */ 51 subs r0, r0, r1 /* bias against r1 so one incr */ 521: cmp r0, r2 /* room for another char? */ 53 beq 2f /* no, write NUL and do the strlen */ 54 ldrb r3, [r1] /* read a byte */ 55 strb r3, [r0, r1] /* write a byte */ 56 adds r1, r1, #1 /* advance to next byte */ 57 cmp r3, #0 /* was it a NUL? */ 58 bne 1b /* no, do next byte */ 59 b 4f /* yes, end of string, so return */ 602: movs r3, #0 /* NUL */ 61 strb r3, [r0] /* write to end of string */ 623: ldrb r3, [r1] /* read a byte */ 63 adds r1, r1, #1 /* advance to next byte */ 64 cmp r3, #0 /* was it a NUL? */ 65 bne 3b /* no, get next byte */ 664: subs r0, r1, r3 /* return length of src string */ 67 RET 68END(_strlcpy) 69#elif defined(STRNCPY) 70/* LINTSTUB: char * strncpy(char *, const char *, size_t) */ 71ENTRY(_strncpy) 72 mov ip, r0 /* we want to preserve r0 */ 73 adds r2, r2, r0 /* get end of dst buffer */ 74 subs r1, r1, r0 /* allows to only increment once */ 751: cmp r0, r2 /* are at the end of dst already? */ 76 beq 3f /* yes, just return. */ 77 ldrb r3, [r1, r0] /* read a byte */ 78 strb r3, [r0] /* write a byte */ 79 adds r0, r0, #1 /* advance a byte */ 80 cmp r3, #0 /* was it a NUL? */ 81 bne 1b /* no, try next byte */ 822: cmp r0, r2 /* are at the end of dst already? */ 83 beq 3f /* yes, exit loop 84 strb r3, [r0] /* write a NUL */ 85 adds r0, r0, #1 /* advance a bytes */ 86 b 2b /* until dst is filled */ 873: mov r0, ip /* return dst pointer */ 88 RET 89END(_strncpy) 90#else 91/* LINTSTUB: char * strcpy(char *, const char *) */ 92ENTRY(_strcpy) 93 subs r2, r0, r1 /* we want to preserve r0 */ 941: ldrb r3, [r1] /* read a byte */ 95 strb r3, [r2, r1] /* write a byte */ 96 adds r1, r1, #1 /* advance to next byte */ 97 cmp r3, #0 /* was it a NUL? */ 98 bne 1b /* no, try next byte */ 99 RET /* return dst pointer */ 100END(_strcpy) 101#endif 102