comparison libgomp/config/linux/mutex.c @ 0:a06113de4d67

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author kent <kent@cr.ie.u-ryukyu.ac.jp>
date Fri, 17 Jul 2009 14:47:48 +0900
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-1:000000000000 0:a06113de4d67
1 /* Copyright (C) 2005, 2008, 2009 Free Software Foundation, Inc.
2 Contributed by Richard Henderson <rth@redhat.com>.
3
4 This file is part of the GNU OpenMP Library (libgomp).
5
6 Libgomp is free software; you can redistribute it and/or modify it
7 under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 3, or (at your option)
9 any later version.
10
11 Libgomp is distributed in the hope that it will be useful, but WITHOUT ANY
12 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
13 FOR A PARTICULAR PURPOSE. See the GNU General Public License for
14 more details.
15
16 Under Section 7 of GPL version 3, you are granted additional
17 permissions described in the GCC Runtime Library Exception, version
18 3.1, as published by the Free Software Foundation.
19
20 You should have received a copy of the GNU General Public License and
21 a copy of the GCC Runtime Library Exception along with this program;
22 see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
23 <http://www.gnu.org/licenses/>. */
24
25 /* This is a Linux specific implementation of a mutex synchronization
26 mechanism for libgomp. This type is private to the library. This
27 implementation uses atomic instructions and the futex syscall. */
28
29 #include "wait.h"
30
31 long int gomp_futex_wake = FUTEX_WAKE | FUTEX_PRIVATE_FLAG;
32 long int gomp_futex_wait = FUTEX_WAIT | FUTEX_PRIVATE_FLAG;
33
34 void
35 gomp_mutex_lock_slow (gomp_mutex_t *mutex)
36 {
37 do
38 {
39 int oldval = __sync_val_compare_and_swap (mutex, 1, 2);
40 if (oldval != 0)
41 do_wait (mutex, 2);
42 }
43 while (!__sync_bool_compare_and_swap (mutex, 0, 2));
44 }
45
46 void
47 gomp_mutex_unlock_slow (gomp_mutex_t *mutex)
48 {
49 futex_wake (mutex, 1);
50 }