xref: /titanic_50/usr/src/lib/libc/i386/gen/memccpy.s (revision 9a70fc3be3b1e966bf78825cdb8d509963a6f0a1)
17c478bd9Sstevel@tonic-gate/*
27c478bd9Sstevel@tonic-gate * CDDL HEADER START
37c478bd9Sstevel@tonic-gate *
47c478bd9Sstevel@tonic-gate * The contents of this file are subject to the terms of the
5*9a70fc3bSMark J. Nelson * Common Development and Distribution License (the "License").
6*9a70fc3bSMark J. Nelson * You may not use this file except in compliance with the License.
77c478bd9Sstevel@tonic-gate *
87c478bd9Sstevel@tonic-gate * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
97c478bd9Sstevel@tonic-gate * or http://www.opensolaris.org/os/licensing.
107c478bd9Sstevel@tonic-gate * See the License for the specific language governing permissions
117c478bd9Sstevel@tonic-gate * and limitations under the License.
127c478bd9Sstevel@tonic-gate *
137c478bd9Sstevel@tonic-gate * When distributing Covered Code, include this CDDL HEADER in each
147c478bd9Sstevel@tonic-gate * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
157c478bd9Sstevel@tonic-gate * If applicable, add the following below this CDDL HEADER, with the
167c478bd9Sstevel@tonic-gate * fields enclosed by brackets "[]" replaced with your own identifying
177c478bd9Sstevel@tonic-gate * information: Portions Copyright [yyyy] [name of copyright owner]
187c478bd9Sstevel@tonic-gate *
197c478bd9Sstevel@tonic-gate * CDDL HEADER END
207c478bd9Sstevel@tonic-gate */
217c478bd9Sstevel@tonic-gate/*
227c478bd9Sstevel@tonic-gate * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
237c478bd9Sstevel@tonic-gate * Use is subject to license terms.
247c478bd9Sstevel@tonic-gate */
257c478bd9Sstevel@tonic-gate
26*9a70fc3bSMark J. Nelson	.file	"memccpy.s"
277c478bd9Sstevel@tonic-gate
287c478bd9Sstevel@tonic-gate#include <sys/asm_linkage.h>
297c478bd9Sstevel@tonic-gate
307c478bd9Sstevel@tonic-gate	ANSI_PRAGMA_WEAK(memccpy,function)
317c478bd9Sstevel@tonic-gate
327c478bd9Sstevel@tonic-gate#include "SYS.h"
337c478bd9Sstevel@tonic-gate
347c478bd9Sstevel@tonic-gate	ENTRY(memccpy)
357c478bd9Sstevel@tonic-gate	pushl	%esi		/ save register variable
367c478bd9Sstevel@tonic-gate	movl	8(%esp),%eax	/ %eax = address of dest string
377c478bd9Sstevel@tonic-gate	movl	12(%esp),%esi	/ %esi = address of source string
387c478bd9Sstevel@tonic-gate	movb	16(%esp),%dh	/ %dh = character to search for
397c478bd9Sstevel@tonic-gate	movl	20(%esp),%ecx	/ %ecx = length to go still
407c478bd9Sstevel@tonic-gate.loop:
417c478bd9Sstevel@tonic-gate	decl	%ecx		/ decrement bytes to go
427c478bd9Sstevel@tonic-gate	jl	.notfound
437c478bd9Sstevel@tonic-gate	movb	(%esi),%dl
447c478bd9Sstevel@tonic-gate	movb	%dl,(%eax)	/ move byte
457c478bd9Sstevel@tonic-gate	cmpb	%dh,%dl		/ is it the byte sought?
467c478bd9Sstevel@tonic-gate	je	.found		/ yes
477c478bd9Sstevel@tonic-gate
487c478bd9Sstevel@tonic-gate	decl	%ecx		/ decrement bytes to go
497c478bd9Sstevel@tonic-gate	jl	.notfound
507c478bd9Sstevel@tonic-gate	movb	1(%esi),%dl
517c478bd9Sstevel@tonic-gate	movb	%dl,1(%eax)	/ move byte
527c478bd9Sstevel@tonic-gate	cmpb	%dh,%dl		/ is it the byte sought?
537c478bd9Sstevel@tonic-gate	je	.found1		/ yes
547c478bd9Sstevel@tonic-gate
557c478bd9Sstevel@tonic-gate	decl	%ecx		/ decrement bytes to go
567c478bd9Sstevel@tonic-gate	jl	.notfound
577c478bd9Sstevel@tonic-gate	movb	2(%esi),%dl
587c478bd9Sstevel@tonic-gate	movb	%dl,2(%eax)	/ move byte
597c478bd9Sstevel@tonic-gate	cmpb	%dh,%dl		/ is it the byte sought?
607c478bd9Sstevel@tonic-gate	je	.found2		/ yes
617c478bd9Sstevel@tonic-gate
627c478bd9Sstevel@tonic-gate	decl	%ecx		/ decrement bytes to go
637c478bd9Sstevel@tonic-gate	jl	.notfound
647c478bd9Sstevel@tonic-gate	movb	3(%esi),%dl
657c478bd9Sstevel@tonic-gate	movb	%dl,3(%eax)	/ move byte
667c478bd9Sstevel@tonic-gate	addl	$4,%esi
677c478bd9Sstevel@tonic-gate	addl	$4,%eax
687c478bd9Sstevel@tonic-gate	cmpb	%dh,%dl		/ is it the byte sought?
697c478bd9Sstevel@tonic-gate	jne	.loop		/ no
707c478bd9Sstevel@tonic-gate	decl	%eax
717c478bd9Sstevel@tonic-gate
727c478bd9Sstevel@tonic-gate.found:
737c478bd9Sstevel@tonic-gate	popl	%esi		/ restore register variable
747c478bd9Sstevel@tonic-gate	incl	%eax		/ return pointer to next byte in dest
757c478bd9Sstevel@tonic-gate	ret
767c478bd9Sstevel@tonic-gate
777c478bd9Sstevel@tonic-gate	.align	4
787c478bd9Sstevel@tonic-gate.found2:
797c478bd9Sstevel@tonic-gate	incl	%eax
807c478bd9Sstevel@tonic-gate.found1:
817c478bd9Sstevel@tonic-gate	popl	%esi		/ restore register variable
827c478bd9Sstevel@tonic-gate	addl	$2,%eax		/ return pointer to next byte in dest
837c478bd9Sstevel@tonic-gate	ret
847c478bd9Sstevel@tonic-gate
857c478bd9Sstevel@tonic-gate	.align	4
867c478bd9Sstevel@tonic-gate.notfound:
877c478bd9Sstevel@tonic-gate	popl	%esi		/ restore register variable
887c478bd9Sstevel@tonic-gate	xorl	%eax,%eax	/ search fails
897c478bd9Sstevel@tonic-gate	ret
907c478bd9Sstevel@tonic-gate	SET_SIZE(memccpy)
91