xref: /illumos-gate/usr/src/lib/libc/amd64/gen/memccpy.S (revision 5d9d9091f564c198a760790b0bfa72c44e17912b)
1*5d9d9091SRichard Lowe/*
2*5d9d9091SRichard Lowe * CDDL HEADER START
3*5d9d9091SRichard Lowe *
4*5d9d9091SRichard Lowe * The contents of this file are subject to the terms of the
5*5d9d9091SRichard Lowe * Common Development and Distribution License (the "License").
6*5d9d9091SRichard Lowe * You may not use this file except in compliance with the License.
7*5d9d9091SRichard Lowe *
8*5d9d9091SRichard Lowe * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9*5d9d9091SRichard Lowe * or http://www.opensolaris.org/os/licensing.
10*5d9d9091SRichard Lowe * See the License for the specific language governing permissions
11*5d9d9091SRichard Lowe * and limitations under the License.
12*5d9d9091SRichard Lowe *
13*5d9d9091SRichard Lowe * When distributing Covered Code, include this CDDL HEADER in each
14*5d9d9091SRichard Lowe * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15*5d9d9091SRichard Lowe * If applicable, add the following below this CDDL HEADER, with the
16*5d9d9091SRichard Lowe * fields enclosed by brackets "[]" replaced with your own identifying
17*5d9d9091SRichard Lowe * information: Portions Copyright [yyyy] [name of copyright owner]
18*5d9d9091SRichard Lowe *
19*5d9d9091SRichard Lowe * CDDL HEADER END
20*5d9d9091SRichard Lowe */
21*5d9d9091SRichard Lowe
22*5d9d9091SRichard Lowe/*
23*5d9d9091SRichard Lowe * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
24*5d9d9091SRichard Lowe * Use is subject to license terms.
25*5d9d9091SRichard Lowe */
26*5d9d9091SRichard Lowe
27*5d9d9091SRichard Lowe	.file	"memccpy.s"
28*5d9d9091SRichard Lowe
29*5d9d9091SRichard Lowe#include <sys/asm_linkage.h>
30*5d9d9091SRichard Lowe
31*5d9d9091SRichard Lowe	ANSI_PRAGMA_WEAK(memccpy,function)
32*5d9d9091SRichard Lowe
33*5d9d9091SRichard Lowe	ENTRY(memccpy)	/* (void *dst, void *src, uchar_t c, size_t) */
34*5d9d9091SRichard Lowe.loop:
35*5d9d9091SRichard Lowe	decq	%rcx		/ decrement bytes to go
36*5d9d9091SRichard Lowe	jl	.notfound
37*5d9d9091SRichard Lowe	movb	(%rsi),%dh
38*5d9d9091SRichard Lowe	movb	%dh,(%rdi)	/ move byte
39*5d9d9091SRichard Lowe	cmpb	%dh,%dl		/ is it the byte sought?
40*5d9d9091SRichard Lowe	je	.found		/ yes
41*5d9d9091SRichard Lowe
42*5d9d9091SRichard Lowe	decq	%rcx		/ decrement bytes to go
43*5d9d9091SRichard Lowe	jl	.notfound
44*5d9d9091SRichard Lowe	movb	1(%rsi),%dh
45*5d9d9091SRichard Lowe	movb	%dh,1(%rdi)	/ move byte
46*5d9d9091SRichard Lowe	cmpb	%dh,%dl		/ is it the byte sought?
47*5d9d9091SRichard Lowe	je	.found1		/ yes
48*5d9d9091SRichard Lowe
49*5d9d9091SRichard Lowe	decq	%rcx		/ decrement bytes to go
50*5d9d9091SRichard Lowe	jl	.notfound
51*5d9d9091SRichard Lowe	movb	2(%rsi),%dh
52*5d9d9091SRichard Lowe	movb	%dh,2(%rdi)	/ move byte
53*5d9d9091SRichard Lowe	cmpb	%dh,%dl		/ is it the byte sought?
54*5d9d9091SRichard Lowe	je	.found2		/ yes
55*5d9d9091SRichard Lowe
56*5d9d9091SRichard Lowe	decq	%rcx		/ decrement bytes to go
57*5d9d9091SRichard Lowe	jl	.notfound
58*5d9d9091SRichard Lowe	movb	3(%rsi),%dh
59*5d9d9091SRichard Lowe	movb	%dh,3(%rdi)	/ move byte
60*5d9d9091SRichard Lowe	addq	$4,%rsi
61*5d9d9091SRichard Lowe	addq	$4,%rdi
62*5d9d9091SRichard Lowe	cmpb	%dh,%dl		/ is it the byte sought?
63*5d9d9091SRichard Lowe	jne	.loop		/ no
64*5d9d9091SRichard Lowe	decq	%rdi
65*5d9d9091SRichard Lowe
66*5d9d9091SRichard Lowe.found:
67*5d9d9091SRichard Lowe	incq	%rdi		/ return pointer to next byte in dest
68*5d9d9091SRichard Lowe	movq	%rdi,%rax
69*5d9d9091SRichard Lowe	ret
70*5d9d9091SRichard Lowe
71*5d9d9091SRichard Lowe	.align	4
72*5d9d9091SRichard Lowe.found2:
73*5d9d9091SRichard Lowe	incq	%rdi
74*5d9d9091SRichard Lowe.found1:
75*5d9d9091SRichard Lowe	addq	$2,%rdi		/ return pointer to next byte in dest
76*5d9d9091SRichard Lowe	movq	%rdi,%rax
77*5d9d9091SRichard Lowe	ret
78*5d9d9091SRichard Lowe
79*5d9d9091SRichard Lowe	.align	4
80*5d9d9091SRichard Lowe.notfound:
81*5d9d9091SRichard Lowe	xorl	%eax,%eax	/ search fails
82*5d9d9091SRichard Lowe	ret
83*5d9d9091SRichard Lowe	SET_SIZE(memccpy)
84