/*      $OpenBSD: strcmp.S,v 1.5 2022/01/29 05:47:36 visa 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 "DEFS.h"


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