strcat.s

早期freebsd实现

/*
 * Copyright (c) 1983, 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.
 */

#if defined(LIBC_SCCS) && !defined(lint)
	.asciz "@(#)strcat.s	8.1 (Berkeley) 6/4/93"
#endif /* LIBC_SCCS and not lint */

/*
 * Concatenate string s2 to the end of s1
 * and return the base of s1.
 *
 * char *
 * strcat(s1, s2)
 *	char *s1, *s2;
 */
#include "DEFS.h"

ENTRY(strcat, R6|R7)
	movq	4(ap), r6	# r6 = s1; r7 = s2
	movl	r6,r1
0:
	locc	$0,$65535,(r1)	# look for '\0'
	beql	0b
	movl	r1,r3		# save end of s1
1:
	locc	$0,$65535,(r7)	# find length of s2
	bneq	2f
	movc3	$65535,(r7),(r3)# copy full block
	movl	r1,r7
	jbr	1b
2:
	subl2	r7,r1		# calculate length
	incl	r1
	movc3	r1,(r7),(r3)	# copy remainder
	movl	r6,r0
	ret