1/*	$NetBSD: rump_atomic_cas_up.c,v 1.1 2010/11/22 10:50:51 pooka Exp $	*/
2
3/*-
4 * Copyright (c) 2010 Antti Kantee.  All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS
16 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
17 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
18 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS
19 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
20 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
21 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
22 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
23 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
24 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
25 * POSSIBILITY OF SUCH DAMAGE.
26 */
27
28#include <sys/cdefs.h>
29__KERNEL_RCSID(0, "$NetBSD: rump_atomic_cas_up.c,v 1.1 2010/11/22 10:50:51 pooka Exp $");
30
31/*
32 * Uniprocessor version of atomic CAS.  Since there is no preemption
33 * in rump, this is a piece of cake.
34 */
35
36#include <sys/types.h>
37
38uint32_t rump_cas_32_up(volatile uint32_t *ptr, uint32_t, uint32_t);
39
40uint32_t
41rump_cas_32_up(volatile uint32_t *ptr, uint32_t old, uint32_t new)
42{
43	uint32_t ret;
44
45	ret = *ptr;
46	if (__predict_true(ret == old)) {
47		*ptr = new;
48	}
49
50	return ret;
51}
52
53__strong_alias(atomic_cas_32,rump_cas_32_up)
54__strong_alias(_atomic_cas_32,rump_cas_32_up)
55__strong_alias(atomic_cas_uint,rump_cas_32_up)
56__strong_alias(_atomic_cas_uint,rump_cas_32_up)
57__strong_alias(atomic_cas_ulong,rump_cas_32_up)
58__strong_alias(_atomic_cas_ulong,rump_cas_32_up)
59__strong_alias(atomic_cas_ptr,rump_cas_32_up)
60__strong_alias(_atomic_cas_ptr,rump_cas_32_up)
61__strong_alias(atomic_cas_32_ni,rump_cas_32_up)
62__strong_alias(_atomic_cas_32_ni,rump_cas_32_up)
63__strong_alias(atomic_cas_uint_ni,rump_cas_32_up)
64__strong_alias(_atomic_cas_uint_ni,rump_cas_32_up)
65__strong_alias(atomic_cas_ulong_ni,rump_cas_32_up)
66__strong_alias(_atomic_cas_ulong_ni,rump_cas_32_up)
67__strong_alias(atomic_cas_ptr_ni,rump_cas_32_up)
68__strong_alias(_atomic_cas_ptr_ni,rump_cas_32_up)
69