| /*- | 
 |  * Copyright (c) 2003 Peter Wemm. | 
 |  * Copyright (c) 1993 The 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. | 
 |  * 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. | 
 |  * | 
 |  * $FreeBSD$ | 
 |  */ | 
 |  | 
 |  | 
 |  | 
 | /* | 
 |  * bcopy(src, dst, cnt) | 
 |  *       rdi, rsi, rdx | 
 |  *  ws@tools.de     (Wolfgang Solfrank, TooLs GmbH) +49-228-985800 | 
 |  */ | 
 | .text | 
 | .align 4 | 
 | .globl bcopy | 
 | .type bcopy,  @function | 
 | bcopy: | 
 | 	xchgq	%rsi,%rdi | 
 | 	movq	%rdx,%rcx | 
 |  | 
 | 	movq	%rdi,%rax | 
 | 	subq	%rsi,%rax | 
 | 	cmpq	%rcx,%rax			/* overlapping && src < dst? */ | 
 | 	jb	1f | 
 |  | 
 | 	shrq	$3,%rcx				/* copy by 64-bit words */ | 
 | 	cld					/* nope, copy forwards */ | 
 | 	rep | 
 | 	movsq | 
 | 	movq	%rdx,%rcx | 
 | 	andq	$7,%rcx				/* any bytes left? */ | 
 | 	rep | 
 | 	movsb | 
 | 	ret | 
 |  | 
 | 	/* ALIGN_TEXT */ | 
 | 1: | 
 | 	addq	%rcx,%rdi			/* copy backwards */ | 
 | 	addq	%rcx,%rsi | 
 | 	decq	%rdi | 
 | 	decq	%rsi | 
 | 	andq	$7,%rcx				/* any fractional bytes? */ | 
 | 	std | 
 | 	rep | 
 | 	movsb | 
 | 	movq	%rdx,%rcx			/* copy remainder by 32-bit words */ | 
 | 	shrq	$3,%rcx | 
 | 	subq	$7,%rsi | 
 | 	subq	$7,%rdi | 
 | 	rep | 
 | 	movsq | 
 | 	cld | 
 | 	ret | 
 | .size bcopy,.-bcopy | 
 |  | 
 |  |