1 /* $NetBSD: atomic_sub_64_cas.c,v 1.3 2014/06/23 21:53:45 joerg Exp $ */
2
3 /*-
4 * Copyright (c) 2014 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 *
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 */
31
32 #include <sys/atomic.h>
33
34 #ifdef __HAVE_ATOMIC64_OPS
35
36 uint64_t fetch_and_sub_8(volatile uint64_t *, uint64_t, ...)
37 asm("__sync_fetch_and_sub_8");
38 uint64_t sub_and_fetch_8(volatile uint64_t *, uint64_t, ...)
39 asm("__sync_sub_and_fetch_8");
40
41 uint64_t
fetch_and_sub_8(volatile uint64_t * addr,uint64_t val,...)42 fetch_and_sub_8(volatile uint64_t *addr, uint64_t val, ...)
43 {
44 uint64_t old, new;
45
46 do {
47 old = *addr;
48 new = old - val;
49 } while (atomic_cas_64(addr, old, new) != old);
50 return old;
51 }
52
53 uint64_t
sub_and_fetch_8(volatile uint64_t * addr,uint64_t val,...)54 sub_and_fetch_8(volatile uint64_t *addr, uint64_t val, ...)
55 {
56 uint64_t old, new;
57
58 do {
59 old = *addr;
60 new = old - val;
61 } while (atomic_cas_64(addr, old, new) != old);
62 return new;
63 }
64
65 __strong_alias(__atomic_fetch_sub_8,__sync_fetch_and_sub_8)
66
67 #endif
68