lib/libc/i386/string/memmove.s

/*-
 * Copyright (c) 1990 The Regents of the University of California.
 * All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 *
 * 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.
 *
 *      $Id: memmove.s,v 1.1 1993/08/16 18:40:36 jtc Exp $
 */

#if defined(LIBC_RCS) && !defined(lint)
        .asciz "$Id: memmove.s,v 1.1 1993/08/16 18:40:36 jtc Exp $"
#endif /* LIBC_RCS and not lint */

#include "DEFS.h"

        /*
         * (ov)bcopy (src,dst,cnt)
         *  ws@tools.de     (Wolfgang Solfrank, TooLs GmbH) +49-228-985800
         */

ALTENTRY(memcpy)
ENTRY(memmove)
        pushl   %esi
        pushl   %edi
        movl    12(%esp),%edi
        pushl   %edi
        movl    20(%esp),%esi
        movl    24(%esp),%ecx
        cmpl    %esi,%edi       /* potentially overlapping? */
        jnb     1f
        cld                     /* nope, copy forwards. */
        shrl    $2,%ecx         /* copy by words */
        rep
        movsl
        movl    24(%esp),%ecx
        andl    $3,%ecx         /* any bytes left? */
        rep
        movsb
        popl    %eax
        popl    %edi
        popl    %esi
        ret
1:
        addl    %ecx,%edi       /* copy backwards. */
        addl    %ecx,%esi
        std
        andl    $3,%ecx         /* any fractional bytes? */
        decl    %edi
        decl    %esi
        rep
        movsb
        movl    24(%esp),%ecx   /* copy remainder by words */
        shrl    $2,%ecx
        subl    $3,%esi
        subl    $3,%edi
        rep
        movsl
        popl    %eax
        popl    %edi
        popl    %esi
        cld
        ret