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// Copyright 2015 Jeff Epler
//
// This program 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 2 of the License, or
// (at your option) any later version.
//
// This program 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.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
#ifndef RTAPI_ATOMIC_H
#define RTAPI_ATOMIC_H
#if defined(__GNUC__) && ((__GNUC__ << 8) | __GNUC_MINOR__) >= 0x409
#define RTAPI_USE_STDATOMIC
#elif defined(__STDC_VERSION__) && __STDC_VERSION > 201112L
#define RTAPI_USE_STDATOMIC
#endif
#ifdef RTAPI_USE_STDATOMIC
#include <stdatomic.h>
#else
enum memory_order {
memory_order_relaxed,
memory_order_consume,
memory_order_acquire,
memory_order_release,
memory_order_acq_rel,
memory_order_seq_cst
};
#define atomic_store(obj, desired) atomic_store_explicit((obj), (desired), memory_order_seq_cst)
#define atomic_load(obj) atomic_load_explicit((obj), memory_order_seq_cst)
// note that in this implementation, only one level of synchronization is supported, equivalent to memory_order_seq_cst
#define atomic_store_explicit(obj, desired, order) \
({ (void)order; __sync_synchronize(); *(obj) = (desired); (void)0; })
#define atomic_load_explicit(obj, order) \
({ (void)order; __typeof__(*(obj)) v = *(obj); __sync_synchronize(); v; })
#endif
#endif
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