atomic_swap_32_cas.c revision 1.1.2.3 
1/*	$NetBSD: atomic_swap_32_cas.c,v 1.1.2.3 2007/04/17 16:05:14 thorpej Exp $	*/
2
3/*-
4 * Copyright (c) 2007 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Jason R. Thorpe.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 *    notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 * 3. All advertising materials mentioning features or use of this software
19 *    must display the following acknowledgement:
20 *	This product includes software developed by the NetBSD
21 *	Foundation, Inc. and its contributors.
22 * 4. Neither the name of The NetBSD Foundation nor the names of its
23 *    contributors may be used to endorse or promote products derived
24 *    from this software without specific prior written permission.
25 *
26 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
27 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
28 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
29 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
30 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
31 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
32 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
33 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
34 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
35 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
36 * POSSIBILITY OF SUCH DAMAGE.
37 */
38
39#include "atomic_op_namespace.h"
40
41#include <sys/atomic.h>
42#include "atomic_op_cas_impl.h"
43
44uint32_t
45atomic_swap_32(volatile uint32_t *addr, uint32_t new)
46{
47	uint32_t old;
48
49	do {
50		OP_READ_BARRIER;
51		old = *addr;
52	} while (atomic_cas_32(addr, old, new) != old);
53
54	return (old);
55}
56
57#undef atomic_swap_32
58atomic_op_alias(atomic_swap_32,_atomic_swap_32)
59#undef atomic_swap_uint
60atomic_op_alias(atomic_swap_uint,_atomic_swap_32)
61#if !defined(_LP64)
62#undef atomic_swap_ulong
63atomic_op_alias(atomic_swap_ulong,_atomic_swap_32)
64#undef atomic_swap_ptr
65atomic_op_alias(atomic_swap_ptr,_atomic_swap_32)
66#endif /* _LP64 */
67