xref: /src/common/lib/libc/arch/mips/string/strcmp.S

/*	$NetBSD: strcmp.S,v 1.2 2009/12/14 00:39:00 matt Exp $	*/

/*-
 * Copyright (c) 1991, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Ralph Campbell.
 *
 * 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.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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 <mips/asm.h>

#if defined(LIBC_SCCS) && !defined(lint)
	/* RCSID("from: @(#)strcmp.s	8.1 (Berkeley) 6/4/93") */
	RCSID("$NetBSD: strcmp.S,v 1.2 2009/12/14 00:39:00 matt Exp $")
#endif /* LIBC_SCCS and not lint */

/*
 * NOTE: this version assumes unsigned chars in order to be "8 bit clean".
 */
LEAF(strcmp)
1:
	lbu	t0, 0(a0)		# get two bytes and compare them
	lbu	t1, 0(a1)
	beq	t0, zero, LessOrEq	# end of first string?
	bne	t0, t1, NotEq
	lbu	t0, 1(a0)		# unroll loop
	lbu	t1, 1(a1)
	PTR_ADD	a0, a0, 2
	beq	t0, zero, LessOrEq	# end of first string?
	PTR_ADD	a1, a1, 2
	beq	t0, t1, 1b
NotEq:
	subu	v0, t0, t1
	j	ra
LessOrEq:
	subu	v0, zero, t1
	j	ra
END(strcmp)