usr/src/lib/libc/tahoe/string/bcopy.s

/*
 * Copyright (c) 1988 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.
 *
 * This code is derived from software contributed to Berkeley by
 * Computer Consoles Inc.
 */

#if defined(LIBC_SCCS) && !defined(lint)
        .asciz "@(#)bcopy.s     1.4 (Berkeley) 6/1/90"
#endif /* LIBC_SCCS and not lint */

/* bcopy(from, to, size) */
#include "DEFS.h"

ENTRY(bcopy, 0)
        movl    4(fp),r0
        movl    8(fp),r1
        movl    12(fp),r2
        cmpl    r0,r1
        bgtru   1f              # normal forward case
        beql    2f              # equal, nothing to do
        addl2   r2,r0           # may be overlapping
        cmpl    r0,r1
        bgtru   3f
        subl2   r2,r0           # normal forward case
1:
        movblk
2:
        ret
3:
        addl2   r2,r1           # overlapping, must do backwards
        subl3   r0,r1,r3
        movl    r2,r4
        jbr     5f
4:
        subl2   r3,r0
        subl2   r3,r1
        movl    r3,r2
        movblk
        subl2   r3,r0
        subl2   r3,r1
        subl2   r3,r4
5:
        cmpl    r4,r3
        jgtr    4b
        movl    r4,r2
        subl2   r2,r0
        subl2   r2,r1
        movblk
        ret