/*      $NetBSD: memccpy.S,v 1.5 2014/03/18 18:20:37 riastradh Exp $    */

/*
 * Copyright (C) 1999 Scott Reynolds.  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. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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 <machine/asm.h>

#if defined(LIBC_SCCS) && !defined(lint)
        RCSID("$NetBSD: memccpy.S,v 1.5 2014/03/18 18:20:37 riastradh Exp $")
#endif /* LIBC_SCCS and not lint */

ENTRY(memccpy)
        movl    16(%sp),%d0             | count
        jeq     Lmcbail                 | nothing to do

        movl    4(%sp),%a0              | a0 = toaddr
#ifndef __mcoldfire__
        subql   #1,%d0                  |   prepare count for DBcc loop
#endif
        movl    8(%sp),%a1              | a1 = fromaddr
        movl    12(%sp),%d1             | d1 = terminator
        jeq     Lmcloop                 |   handle ASCII NUL specially

        movl    %d2,-(%sp)              | save scratch register
Lmcnzloop:
        movb    (%a1)+,%d2              | move a byte
        movb    %d2,(%a0)+
        cmpb    %d2,%d1                 | found the terminator?
#ifndef __mcoldfire__
        dbeq    %d0,Lmcnzloop           | if not, keep transferring,
#endif
        jeq     Lmcnzdone               |   otherwise done
#ifdef __mcoldfire__
        subql   #1,%d0
        jne     Lmcnzloop
#else
        clrw    %d0                     | check to see if more to do
        subql   #1,%d0
        jcc     Lmcnzloop               | yes, keep going...
#endif

        movl    (%sp)+,%d2              | restore scratch register
        movql   #0,%d0                  | no terminator found, return NULL
#ifdef __SVR4_ABI__
        movl    %d0,%a0                 | XXX maybe use lea to avoid stall?
#endif
        rts

Lmcloop:
        movb    (%a1)+,(%a0)+           | move a byte; was it NUL?
#ifndef __mcoldfire__
        dbeq    %d0,Lmcloop             | if not, keep transferring,
#endif
        jeq     Lmcdone                 |   otherwise done
#ifdef __mcoldfire__
        subql   #1,%d0
        jne     Lmcloop
#else
        clrw    %d0                     | check to see if more to do
        subql   #1,%d0
        jcc     Lmcloop                 | yes, keep going...
#endif
                                        | Note: %d0 is now -1!
        movql   #0,%d0                  | no terminator found, return NULL
Lmcbail:
#ifdef __SVR4_ABI__
        movl    %d0,%a0                 | XXX maybe use lea to avoid stall?
#endif
        rts

Lmcnzdone:
        movl    (%sp)+,%d2              | restore scratch register
Lmcdone:
        movl    %a0,%d0
        rts
END(memccpy)