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bcopy.S revision 1.1 
      1 /*-
      2  * Copyright (c) 1990 The Regents of the University of California.
      3  * All rights reserved.
      4  *
      5  * This code is derived from locore.s.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  * 3. Neither the name of the University nor the names of its contributors
     16  *    may be used to endorse or promote products derived from this software
     17  *    without specific prior written permission.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     29  * SUCH DAMAGE.
     30  */
     31 
     32 #include <machine/asm.h>
     33 
     34 #if defined(LIBC_SCCS)
     35 	RCSID("$NetBSD: bcopy.S,v 1.1 2005/12/20 19:28:51 christos Exp $")
     36 #endif
     37 
     38 	/*
     39 	 * (ov)bcopy (src,dst,cnt)
     40 	 *  ws (at) tools.de     (Wolfgang Solfrank, TooLs GmbH) +49-228-985800
     41 	 */
     42 
     43 #ifdef MEMCOPY
     44 ENTRY(memcpy)
     45 #else
     46 #ifdef MEMMOVE
     47 ENTRY(memmove)
     48 #else
     49 ENTRY(bcopy)
     50 #endif
     51 #endif
     52 #if defined(MEMCOPY) || defined(MEMMOVE)
     53 	movq	%rdi,%r11	/* save dest */
     54 #else
     55 	xchgq	%rdi,%rsi
     56 #endif
     57 	movq	%rdx,%rcx
     58 	movq	%rdi,%rax
     59 	subq	%rsi,%rax
     60 	cmpq	%rcx,%rax	/* overlapping? */
     61 	jb	1f
     62 	cld			/* nope, copy forwards. */
     63 	shrq	$3,%rcx		/* copy by words */
     64 	rep
     65 	movsq
     66 	movq	%rdx,%rcx
     67 	andq	$7,%rcx		/* any bytes left? */
     68 	rep
     69 	movsb
     70 #if defined(MEMCOPY) || defined(MEMMOVE)
     71 	movq	%r11,%rax
     72 #endif
     73 	ret
     74 1:
     75 	addq	%rcx,%rdi	/* copy backwards. */
     76 	addq	%rcx,%rsi
     77 	std
     78 	andq	$7,%rcx		/* any fractional bytes? */
     79 	decq	%rdi
     80 	decq	%rsi
     81 	rep
     82 	movsb
     83 	movq	%rdx,%rcx	/* copy remainder by words */
     84 	shrq	$3,%rcx
     85 	subq	$7,%rsi
     86 	subq	$7,%rdi
     87 	rep
     88 	movsq
     89 #if defined(MEMCOPY) || defined(MEMMOVE)
     90 	movq	%r11,%rax
     91 #endif
     92 	cld
     93 	ret
     94