xref: /onnv-gate/usr/src/lib/libc/amd64/gen/memccpy.s (revision 7298:b69e27387f74)
10Sstevel@tonic-gate/*
20Sstevel@tonic-gate * CDDL HEADER START
30Sstevel@tonic-gate *
40Sstevel@tonic-gate * The contents of this file are subject to the terms of the
56812Sraf * Common Development and Distribution License (the "License").
66812Sraf * You may not use this file except in compliance with the License.
70Sstevel@tonic-gate *
80Sstevel@tonic-gate * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
90Sstevel@tonic-gate * or http://www.opensolaris.org/os/licensing.
100Sstevel@tonic-gate * See the License for the specific language governing permissions
110Sstevel@tonic-gate * and limitations under the License.
120Sstevel@tonic-gate *
130Sstevel@tonic-gate * When distributing Covered Code, include this CDDL HEADER in each
140Sstevel@tonic-gate * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
150Sstevel@tonic-gate * If applicable, add the following below this CDDL HEADER, with the
160Sstevel@tonic-gate * fields enclosed by brackets "[]" replaced with your own identifying
170Sstevel@tonic-gate * information: Portions Copyright [yyyy] [name of copyright owner]
180Sstevel@tonic-gate *
190Sstevel@tonic-gate * CDDL HEADER END
200Sstevel@tonic-gate */
216812Sraf
220Sstevel@tonic-gate/*
236812Sraf * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
240Sstevel@tonic-gate * Use is subject to license terms.
250Sstevel@tonic-gate */
260Sstevel@tonic-gate
27*7298SMark.J.Nelson@Sun.COM	.file	"memccpy.s"
280Sstevel@tonic-gate
290Sstevel@tonic-gate#include <sys/asm_linkage.h>
300Sstevel@tonic-gate
310Sstevel@tonic-gate	ANSI_PRAGMA_WEAK(memccpy,function)
320Sstevel@tonic-gate
330Sstevel@tonic-gate	ENTRY(memccpy)	/* (void *dst, void *src, uchar_t c, size_t) */
340Sstevel@tonic-gate.loop:
350Sstevel@tonic-gate	decq	%rcx		/ decrement bytes to go
360Sstevel@tonic-gate	jl	.notfound
370Sstevel@tonic-gate	movb	(%rsi),%dh
380Sstevel@tonic-gate	movb	%dh,(%rdi)	/ move byte
390Sstevel@tonic-gate	cmpb	%dh,%dl		/ is it the byte sought?
400Sstevel@tonic-gate	je	.found		/ yes
410Sstevel@tonic-gate
420Sstevel@tonic-gate	decq	%rcx		/ decrement bytes to go
430Sstevel@tonic-gate	jl	.notfound
440Sstevel@tonic-gate	movb	1(%rsi),%dh
450Sstevel@tonic-gate	movb	%dh,1(%rdi)	/ move byte
460Sstevel@tonic-gate	cmpb	%dh,%dl		/ is it the byte sought?
470Sstevel@tonic-gate	je	.found1		/ yes
480Sstevel@tonic-gate
490Sstevel@tonic-gate	decq	%rcx		/ decrement bytes to go
500Sstevel@tonic-gate	jl	.notfound
510Sstevel@tonic-gate	movb	2(%rsi),%dh
520Sstevel@tonic-gate	movb	%dh,2(%rdi)	/ move byte
530Sstevel@tonic-gate	cmpb	%dh,%dl		/ is it the byte sought?
540Sstevel@tonic-gate	je	.found2		/ yes
550Sstevel@tonic-gate
560Sstevel@tonic-gate	decq	%rcx		/ decrement bytes to go
570Sstevel@tonic-gate	jl	.notfound
580Sstevel@tonic-gate	movb	3(%rsi),%dh
590Sstevel@tonic-gate	movb	%dh,3(%rdi)	/ move byte
600Sstevel@tonic-gate	addq	$4,%rsi
610Sstevel@tonic-gate	addq	$4,%rdi
620Sstevel@tonic-gate	cmpb	%dh,%dl		/ is it the byte sought?
630Sstevel@tonic-gate	jne	.loop		/ no
640Sstevel@tonic-gate	decq	%rdi
650Sstevel@tonic-gate
660Sstevel@tonic-gate.found:
670Sstevel@tonic-gate	incq	%rdi		/ return pointer to next byte in dest
680Sstevel@tonic-gate	movq	%rdi,%rax
690Sstevel@tonic-gate	ret
700Sstevel@tonic-gate
710Sstevel@tonic-gate	.align	4
720Sstevel@tonic-gate.found2:
730Sstevel@tonic-gate	incq	%rdi
740Sstevel@tonic-gate.found1:
750Sstevel@tonic-gate	addq	$2,%rdi		/ return pointer to next byte in dest
760Sstevel@tonic-gate	movq	%rdi,%rax
770Sstevel@tonic-gate	ret
780Sstevel@tonic-gate
790Sstevel@tonic-gate	.align	4
800Sstevel@tonic-gate.notfound:
810Sstevel@tonic-gate	xorl	%eax,%eax	/ search fails
820Sstevel@tonic-gate	ret
830Sstevel@tonic-gate	SET_SIZE(memccpy)
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