xref: /titanic_41/usr/src/uts/intel/ia32/ml/ovbcopy.s (revision 936b7af69172dce89b577831f79c0e18d15e854b)
1/*
2 * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
3 * Use is subject to license terms.
4 */
5
6#pragma ident	"%Z%%M%	%I%	%E% SMI"
7
8/*-
9 * Copyright (c) 1993 The Regents of the University of California.
10 * All rights reserved.
11 *
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions
14 * are met:
15 * 1. Redistributions of source code must retain the above copyright
16 *    notice, this list of conditions and the following disclaimer.
17 * 2. Redistributions in binary form must reproduce the above copyright
18 *    notice, this list of conditions and the following disclaimer in the
19 *    documentation and/or other materials provided with the distribution.
20 * 3. All advertising materials mentioning features or use of this software
21 *    must display the following acknowledgement:
22 *	This product includes software developed by the University of
23 *	California, Berkeley and its contributors.
24 * 4. Neither the name of the University nor the names of its contributors
25 *    may be used to endorse or promote products derived from this software
26 *    without specific prior written permission.
27 *
28 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
29 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
30 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
31 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
32 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
33 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
34 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
35 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
36 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
37 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
38 * SUCH DAMAGE.
39 *
40 * $FreeBSD: src/sys/amd64/amd64/support.S,v 1.102 2003/10/02 05:08:13 alc Exp $
41 */
42
43#include <sys/asm_linkage.h>
44
45#if defined(__lint)
46
47/*
48 * Overlapping bcopy (source and target may overlap arbitrarily).
49 */
50/* ARGSUSED */
51void
52ovbcopy(const void *from, void *to, size_t count)
53{}
54
55#else	/* __lint */
56
57/*
58 * Adapted from fbsd bcopy().
59 *
60 * bcopy(src, dst, cnt)
61 *       rdi, rsi, rdx
62 *  ws@tools.de     (Wolfgang Solfrank, TooLs GmbH) +49-228-985800
63 */
64
65#if defined(__amd64)
66
67	ENTRY(ovbcopy)
68	xchgq	%rsi,%rdi
69	movq	%rdx,%rcx
70
71	movq	%rdi,%rax
72	subq	%rsi,%rax
73	cmpq	%rcx,%rax		/* overlapping && src < dst? */
74	jb	reverse
75
76	shrq	$3,%rcx			/* copy by 64-bit words */
77	cld				/* nope, copy forwards */
78	rep
79	movsq
80	movq	%rdx,%rcx
81	andq	$7,%rcx			/* any bytes left? */
82	rep
83	movsb
84	ret
85
86reverse:
87	addq	%rcx,%rdi		/* copy backwards */
88	addq	%rcx,%rsi
89	decq	%rdi
90	decq	%rsi
91	andq	$7,%rcx			/* any fractional bytes? */
92	std
93	rep
94	movsb
95	movq	%rdx,%rcx		/* copy remainder by 32-bit words */
96	shrq	$3,%rcx
97	subq	$7,%rsi
98	subq	$7,%rdi
99	rep
100	movsq
101	cld
102	ret
103	SET_SIZE(ovbcopy)
104
105#elif defined(__i386)
106
107	ENTRY(ovbcopy)
108	pushl	%esi
109	pushl	%edi
110	movl	12(%esp),%esi
111	movl	16(%esp),%edi
112	movl	20(%esp),%ecx
113
114	movl	%edi,%eax
115	subl	%esi,%eax
116	cmpl	%ecx,%eax		/* overlapping && src < dst? */
117	jb	reverse
118
119	shrl	$2,%ecx			/* copy by 32-bit words */
120	cld				/* nope, copy forwards */
121	rep
122	movsl
123	movl	20(%esp),%ecx
124	andl	$3,%ecx			/* any bytes left? */
125	rep
126	movsb
127	popl	%edi
128	popl	%esi
129	ret
130
131reverse:
132	addl	%ecx,%edi		/* copy backwards */
133	addl	%ecx,%esi
134	decl	%edi
135	decl	%esi
136	andl	$3,%ecx			/* any fractional bytes? */
137	std
138	rep
139	movsb
140	movl	20(%esp),%ecx		/* copy remainder by 32-bit words */
141	shrl	$2,%ecx
142	subl	$3,%esi
143	subl	$3,%edi
144	rep
145	movsl
146	popl	%edi
147	popl	%esi
148	cld
149	ret
150	SET_SIZE(ovbcopy)
151
152#endif	/* __i386 */
153
154#endif	/* __lint */
155