1 /* $NetBSD: rump_atomic_cas_up.c,v 1.2 2010/11/23 12:51:10 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 1.2 2010/11/23 12:51:10 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
38 uint32_t rump_cas_32_up(volatile uint32_t *ptr, uint32_t, uint32_t);
39
40 uint32_t
rump_cas_32_up(volatile uint32_t * ptr,uint32_t old,uint32_t new)41 rump_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