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blkcpy.S revision 1.4 
      1 /*	$NetBSD: blkcpy.S,v 1.4 2005/12/11 12:24:45 christos Exp $	*/
      2 /*
      3  * Copyright (c) 1983, 1993
      4  *	The Regents of the University of California.  All rights reserved.
      5  *
      6  * Redistribution and use in source and binary forms, with or without
      7  * modification, are permitted provided that the following conditions
      8  * are met:
      9  * 1. Redistributions of source code must retain the above copyright
     10  *    notice, this list of conditions and the following disclaimer.
     11  * 2. Redistributions in binary form must reproduce the above copyright
     12  *    notice, this list of conditions and the following disclaimer in the
     13  *    documentation and/or other materials provided with the distribution.
     14  * 3. Neither the name of the University nor the names of its contributors
     15  *    may be used to endorse or promote products derived from this software
     16  *    without specific prior written permission.
     17  *
     18  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     19  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     20  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     21  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     22  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     23  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     24  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     25  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     26  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     27  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     28  * SUCH DAMAGE.
     29  */
     30 #include <machine/asm.h>
     31 
     32 /* __blkcpy(from, to, size) */
     33 
     34 ENTRY(__blkcpy, R6)
     35 	movl	4(%ap),%r1
     36 	movl	8(%ap),%r3
     37 	movl	12(%ap),%r6
     38 	cmpl	%r1,%r3
     39 	bgtr	2f		# normal forward case
     40 	blss	3f		# overlapping, must do backwards
     41 	ret			# equal, nothing to do
     42 1:
     43 	subl2	%r0,%r6
     44 	movc3	%r0,(%r1),(%r3)
     45 2:
     46 	movzwl	$65535,%r0
     47 	cmpl	%r6,%r0
     48 	jgtr	1b
     49 	movc3	%r6,(%r1),(%r3)
     50 	ret
     51 3:
     52 	addl2	%r6,%r1
     53 	addl2	%r6,%r3
     54 	movzwl	$65535,%r0
     55 	jbr	5f
     56 4:
     57 	subl2	%r0,%r6
     58 	subl2	%r0,%r1
     59 	subl2	%r0,%r3
     60 	movc3	%r0,(%r1),(%r3)
     61 	movzwl	$65535,%r0
     62 	subl2	%r0,%r1
     63 	subl2	%r0,%r3
     64 5:
     65 	cmpl	%r6,%r0
     66 	jgtr	4b
     67 	subl2	%r6,%r1
     68 	subl2	%r6,%r3
     69 	movc3	%r6,(%r1),(%r3)
     70 	ret
     71