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      1 /*
      2  * CDDL HEADER START
      3  *
      4  * The contents of this file are subject to the terms of the
      5  * Common Development and Distribution License (the "License").
      6  * You may not use this file except in compliance with the License.
      7  *
      8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
      9  * or http://www.opensolaris.org/os/licensing.
     10  * See the License for the specific language governing permissions
     11  * and limitations under the License.
     12  *
     13  * When distributing Covered Code, include this CDDL HEADER in each
     14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
     15  * If applicable, add the following below this CDDL HEADER, with the
     16  * fields enclosed by brackets "[]" replaced with your own identifying
     17  * information: Portions Copyright [yyyy] [name of copyright owner]
     18  *
     19  * CDDL HEADER END
     20  */
     21 
     22 /*
     23  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
     24  * Use is subject to license terms.
     25  */
     26 
     27 	.file	"memccpy.s"
     28 
     29 #include <sys/asm_linkage.h>
     30 
     31 	ANSI_PRAGMA_WEAK(memccpy,function)
     32 
     33 	ENTRY(memccpy)	/* (void *dst, void *src, uchar_t c, size_t) */
     34 .loop:
     35 	decq	%rcx		/ decrement bytes to go
     36 	jl	.notfound
     37 	movb	(%rsi),%dh
     38 	movb	%dh,(%rdi)	/ move byte
     39 	cmpb	%dh,%dl		/ is it the byte sought?
     40 	je	.found		/ yes
     41 
     42 	decq	%rcx		/ decrement bytes to go
     43 	jl	.notfound
     44 	movb	1(%rsi),%dh
     45 	movb	%dh,1(%rdi)	/ move byte
     46 	cmpb	%dh,%dl		/ is it the byte sought?
     47 	je	.found1		/ yes
     48 
     49 	decq	%rcx		/ decrement bytes to go
     50 	jl	.notfound
     51 	movb	2(%rsi),%dh
     52 	movb	%dh,2(%rdi)	/ move byte
     53 	cmpb	%dh,%dl		/ is it the byte sought?
     54 	je	.found2		/ yes
     55 
     56 	decq	%rcx		/ decrement bytes to go
     57 	jl	.notfound
     58 	movb	3(%rsi),%dh
     59 	movb	%dh,3(%rdi)	/ move byte
     60 	addq	$4,%rsi
     61 	addq	$4,%rdi
     62 	cmpb	%dh,%dl		/ is it the byte sought?
     63 	jne	.loop		/ no
     64 	decq	%rdi
     65 
     66 .found:
     67 	incq	%rdi		/ return pointer to next byte in dest
     68 	movq	%rdi,%rax
     69 	ret
     70 
     71 	.align	4
     72 .found2:
     73 	incq	%rdi
     74 .found1:
     75 	addq	$2,%rdi		/ return pointer to next byte in dest
     76 	movq	%rdi,%rax
     77 	ret
     78 
     79 	.align	4
     80 .notfound:
     81 	xorl	%eax,%eax	/ search fails
     82 	ret
     83 	SET_SIZE(memccpy)
     84