xref: /titanic_51/usr/src/lib/libc/amd64/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
57257d1b4Sraf * Common Development and Distribution License (the "License").
67257d1b4Sraf * 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 */
217257d1b4Sraf
227c478bd9Sstevel@tonic-gate/*
237257d1b4Sraf * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
247c478bd9Sstevel@tonic-gate * Use is subject to license terms.
257c478bd9Sstevel@tonic-gate */
267c478bd9Sstevel@tonic-gate
27*9a70fc3bSMark J. Nelson	.file	"memccpy.s"
287c478bd9Sstevel@tonic-gate
297c478bd9Sstevel@tonic-gate#include <sys/asm_linkage.h>
307c478bd9Sstevel@tonic-gate
317c478bd9Sstevel@tonic-gate	ANSI_PRAGMA_WEAK(memccpy,function)
327c478bd9Sstevel@tonic-gate
337c478bd9Sstevel@tonic-gate	ENTRY(memccpy)	/* (void *dst, void *src, uchar_t c, size_t) */
347c478bd9Sstevel@tonic-gate.loop:
357c478bd9Sstevel@tonic-gate	decq	%rcx		/ decrement bytes to go
367c478bd9Sstevel@tonic-gate	jl	.notfound
377c478bd9Sstevel@tonic-gate	movb	(%rsi),%dh
387c478bd9Sstevel@tonic-gate	movb	%dh,(%rdi)	/ move byte
397c478bd9Sstevel@tonic-gate	cmpb	%dh,%dl		/ is it the byte sought?
407c478bd9Sstevel@tonic-gate	je	.found		/ yes
417c478bd9Sstevel@tonic-gate
427c478bd9Sstevel@tonic-gate	decq	%rcx		/ decrement bytes to go
437c478bd9Sstevel@tonic-gate	jl	.notfound
447c478bd9Sstevel@tonic-gate	movb	1(%rsi),%dh
457c478bd9Sstevel@tonic-gate	movb	%dh,1(%rdi)	/ move byte
467c478bd9Sstevel@tonic-gate	cmpb	%dh,%dl		/ is it the byte sought?
477c478bd9Sstevel@tonic-gate	je	.found1		/ yes
487c478bd9Sstevel@tonic-gate
497c478bd9Sstevel@tonic-gate	decq	%rcx		/ decrement bytes to go
507c478bd9Sstevel@tonic-gate	jl	.notfound
517c478bd9Sstevel@tonic-gate	movb	2(%rsi),%dh
527c478bd9Sstevel@tonic-gate	movb	%dh,2(%rdi)	/ move byte
537c478bd9Sstevel@tonic-gate	cmpb	%dh,%dl		/ is it the byte sought?
547c478bd9Sstevel@tonic-gate	je	.found2		/ yes
557c478bd9Sstevel@tonic-gate
567c478bd9Sstevel@tonic-gate	decq	%rcx		/ decrement bytes to go
577c478bd9Sstevel@tonic-gate	jl	.notfound
587c478bd9Sstevel@tonic-gate	movb	3(%rsi),%dh
597c478bd9Sstevel@tonic-gate	movb	%dh,3(%rdi)	/ move byte
607c478bd9Sstevel@tonic-gate	addq	$4,%rsi
617c478bd9Sstevel@tonic-gate	addq	$4,%rdi
627c478bd9Sstevel@tonic-gate	cmpb	%dh,%dl		/ is it the byte sought?
637c478bd9Sstevel@tonic-gate	jne	.loop		/ no
647c478bd9Sstevel@tonic-gate	decq	%rdi
657c478bd9Sstevel@tonic-gate
667c478bd9Sstevel@tonic-gate.found:
677c478bd9Sstevel@tonic-gate	incq	%rdi		/ return pointer to next byte in dest
687c478bd9Sstevel@tonic-gate	movq	%rdi,%rax
697c478bd9Sstevel@tonic-gate	ret
707c478bd9Sstevel@tonic-gate
717c478bd9Sstevel@tonic-gate	.align	4
727c478bd9Sstevel@tonic-gate.found2:
737c478bd9Sstevel@tonic-gate	incq	%rdi
747c478bd9Sstevel@tonic-gate.found1:
757c478bd9Sstevel@tonic-gate	addq	$2,%rdi		/ return pointer to next byte in dest
767c478bd9Sstevel@tonic-gate	movq	%rdi,%rax
777c478bd9Sstevel@tonic-gate	ret
787c478bd9Sstevel@tonic-gate
797c478bd9Sstevel@tonic-gate	.align	4
807c478bd9Sstevel@tonic-gate.notfound:
817c478bd9Sstevel@tonic-gate	xorl	%eax,%eax	/ search fails
827c478bd9Sstevel@tonic-gate	ret
837c478bd9Sstevel@tonic-gate	SET_SIZE(memccpy)
84