vaxbsubs.s

早期freebsd实现

/*-
 * Copyright (c) 1988, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * 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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. 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.
 *
 *	@(#)vaxbsubs.s	8.1 (Berkeley) 6/6/93
 */

/* This is taken from bcmp.s from 4.2.
 * The output of bunequal is the offset of the byte which didn't match;
 * if all the bytes match, then we return n.
 *
 * BUGNOTE:  This has no chance of working for lengths greater than 64K.
 *		(so, if you use this somewhere else, you may need to
 *		fix it...)
 */

/* bunequal(s1, s2, n) */

#include "defs.h"

ENTRY(bunequal)
	movl	4(ap),r1
	movl	8(ap),r3
	movl	12(ap),r4
1:
	movzwl	$65535,r0
	cmpl	r4,r0
	jleq	2f
	subl2	r0,r4
	cmpc3	r0,(r1),(r3)
	jeql	1b
	addl2	r4,r0
	/* changes... */
	subl3	r0,12(ap),r0
	/* end of changes for bunequal... */
	ret
2:
	cmpc3	r4,(r1),(r3)
	/* changes... */
	subl3	r0,12(ap),r0
	/* end of changes for bunequal... */
	ret




/* brand new code, using the above as base... */
/* bskip(s1, n, b) : finds the first occurrence of any byte != 'b' in the 'n'
 * bytes beginning at 's1'.
 *
 * BUGNOTE:  This has no chance of working for lengths greater than 64K.
 *		(so, if you use this somewhere else, you may need to
 *		fix it...)
 */

ENTRY(bskip)
	movl	4(ap),r1
	movl	8(ap),r3
	movl	12(ap),r4
1:
	movzwl	$65535,r0
	cmpl	r3,r0
	jleq	2f
	subl2	r0,r3
	skpc	r4,r0,(r1)
	jeql	1b
	addl2	r3,r0
	subl3	r0,8(ap),r0
	ret
2:
	skpc	r4,r3,(r1)
	subl3	r0,8(ap),r0
	ret