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