68 lines
2.1 KiB
C
68 lines
2.1 KiB
C
/* Copyright (C) 2005-2018 Free Software Foundation, Inc.
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Contributed by Richard Henderson <rth@redhat.com>.
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This file is part of the GNU Offloading and Multi Processing Library
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(libgomp).
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Libgomp is free software; you can redistribute it and/or modify it
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under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3, or (at your option)
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any later version.
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Libgomp is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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more details.
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Under Section 7 of GPL version 3, you are granted additional
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permissions described in the GCC Runtime Library Exception, version
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3.1, as published by the Free Software Foundation.
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You should have received a copy of the GNU General Public License and
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a copy of the GCC Runtime Library Exception along with this program;
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see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
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<http://www.gnu.org/licenses/>. */
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/* This is a Linux specific implementation of a mutex synchronization
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mechanism for libgomp. This type is private to the library. This
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implementation uses atomic instructions and the futex syscall. */
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#ifndef GOMP_MUTEX_H
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#define GOMP_MUTEX_H 1
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typedef int gomp_mutex_t;
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#define GOMP_MUTEX_INIT_0 1
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extern void gomp_mutex_lock_slow (gomp_mutex_t *mutex, int);
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extern void gomp_mutex_unlock_slow (gomp_mutex_t *mutex);
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static inline void
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gomp_mutex_init (gomp_mutex_t *mutex)
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{
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*mutex = 0;
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}
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static inline void
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gomp_mutex_destroy (gomp_mutex_t *mutex)
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{
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}
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static inline void
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gomp_mutex_lock (gomp_mutex_t *mutex)
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{
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int oldval = 0;
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if (!__atomic_compare_exchange_n (mutex, &oldval, 1, false,
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MEMMODEL_ACQUIRE, MEMMODEL_RELAXED))
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gomp_mutex_lock_slow (mutex, oldval);
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}
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static inline void
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gomp_mutex_unlock (gomp_mutex_t *mutex)
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{
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int wait = __atomic_exchange_n (mutex, 0, MEMMODEL_RELEASE);
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if (__builtin_expect (wait < 0, 0))
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gomp_mutex_unlock_slow (mutex);
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}
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#endif /* GOMP_MUTEX_H */
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