minix/common/lib/libc/arch/arm/string/strcpy_thumb.S

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/*-
* 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: strcpy_thumb.S,v 1.1 2013/08/20 21:32:50 matt Exp $")
#ifdef _LIBC
#ifdef STRLCPY
WEAK_ALIAS(strlcpy, _strlcpy)
#endif
#include "namespace.h"
#endif
/*
* These are "naive" versions of the str*cpy routines designed to be simple
* and small.
*/
#if defined(STRLCPY)
/* LINTSTUB: size_t strlcpy(char *, const char *, size_t) */
ENTRY(strlcpy)
adds r3, r1, #1 /* save src pointer (+ NUL) */
subs r2, r2, #1 /* make sure there's room for a NUL */
blt 3f /* no room, do the strlen */
adds r2, r2, r0 /* get end of dst */
subs r0, r0, r1 /* bias against r1 so one incr */
1: cmp r0, r2 /* room for another char? */
beq 2f /* no, write NUL and do the strlen */
ldrb r3, [r1] /* read a byte */
strb r3, [r0, r1] /* write a byte */
adds r1, r1, #1 /* advance to next byte */
cmp r3, #0 /* was it a NUL? */
bne 1b /* no, do next byte */
b 4f /* yes, end of string, so return */
2: movs r3, #0 /* NUL */
strb r3, [r0] /* write to end of string */
3: ldrb r3, [r1] /* read a byte */
adds r1, r1, #1 /* advance to next byte */
cmp r3, #0 /* was it a NUL? */
bne 3b /* no, get next byte */
4: subs r0, r1, r3 /* return length of src string */
RET
END(strlcpy)
#elif defined(STRNCPY)
/* LINTSTUB: char * strncpy(char *, const char *, size_t) */
ENTRY(strncpy)
mov ip, r0 /* we want to preserve r0 */
adds r2, r2, r0 /* get end of dst buffer */
subs r1, r1, r0 /* allows to only increment once */
1: cmp r0, r2 /* are at the end of dst already? */
beq 3f /* yes, just return. */
ldrb r3, [r1, r0] /* read a byte */
strb r3, [r0] /* write a byte */
adds r0, r0, #1 /* advance a byte */
cmp r3, #0 /* was it a NUL? */
bne 1b /* no, try next byte */
2: cmp r0, r2 /* are at the end of dst already? */
beq 3f /* yes, exit loop
strb r3, [r0] /* write a NUL */
adds r0, r0, #1 /* advance a bytes */
b 2b /* until dst is filled */
3: mov r0, ip /* return dst pointer */
RET
END(strncpy)
#else
/* LINTSTUB: char * strcpy(char *, const char *) */
ENTRY(strcpy)
subs r2, r0, r1 /* we want to preserve r0 */
1: ldrb r3, [r1] /* read a byte */
strb r3, [r2, r1] /* write a byte */
adds r1, r1, #1 /* advance to next byte */
cmp r3, #0 /* was it a NUL? */
bne 1b /* no, try next byte */
RET /* return dst pointer */
END(strcpy)
#endif