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+/*
+ * Distributed under the Boost Software License, Version 1.0.
+ * (See accompanying file LICENSE_1_0.txt or copy at
+ * http://www.boost.org/LICENSE_1_0.txt)
+ *
+ * Copyright (c) 2011 Helge Bahmann
+ * Copyright (c) 2013 Tim Blechmann
+ * Copyright (c) 2014 Andrey Semashev
+ */
+/*!
+ * \file atomic/detail/ops_gcc_sync.hpp
+ *
+ * This header contains implementation of the \c operations template.
+ */
+
+#ifndef BOOST_ATOMIC_DETAIL_OPS_GCC_SYNC_HPP_INCLUDED_
+#define BOOST_ATOMIC_DETAIL_OPS_GCC_SYNC_HPP_INCLUDED_
+
+#include <boost/memory_order.hpp>
+#include <boost/atomic/detail/config.hpp>
+#include <boost/atomic/detail/storage_type.hpp>
+#include <boost/atomic/detail/operations_fwd.hpp>
+#include <boost/atomic/detail/ops_extending_cas_based.hpp>
+#include <boost/atomic/capabilities.hpp>
+
+#ifdef BOOST_HAS_PRAGMA_ONCE
+#pragma once
+#endif
+
+namespace boost {
+namespace atomics {
+namespace detail {
+
+struct gcc_sync_operations_base
+{
+ static BOOST_FORCEINLINE void fence_before_store(memory_order order) BOOST_NOEXCEPT
+ {
+ if ((order & memory_order_release) != 0)
+ __sync_synchronize();
+ }
+
+ static BOOST_FORCEINLINE void fence_after_store(memory_order order) BOOST_NOEXCEPT
+ {
+ if (order == memory_order_seq_cst)
+ __sync_synchronize();
+ }
+
+ static BOOST_FORCEINLINE void fence_after_load(memory_order order) BOOST_NOEXCEPT
+ {
+ if ((order & (memory_order_acquire | memory_order_consume)) != 0)
+ __sync_synchronize();
+ }
+};
+
+template< typename T >
+struct gcc_sync_operations :
+ public gcc_sync_operations_base
+{
+ typedef T storage_type;
+
+ static BOOST_FORCEINLINE void store(storage_type volatile& storage, storage_type v, memory_order order) BOOST_NOEXCEPT
+ {
+ fence_before_store(order);
+ storage = v;
+ fence_after_store(order);
+ }
+
+ static BOOST_FORCEINLINE storage_type load(storage_type const volatile& storage, memory_order order) BOOST_NOEXCEPT
+ {
+ storage_type v = storage;
+ fence_after_load(order);
+ return v;
+ }
+
+ static BOOST_FORCEINLINE storage_type fetch_add(storage_type volatile& storage, storage_type v, memory_order) BOOST_NOEXCEPT
+ {
+ return __sync_fetch_and_add(&storage, v);
+ }
+
+ static BOOST_FORCEINLINE storage_type fetch_sub(storage_type volatile& storage, storage_type v, memory_order) BOOST_NOEXCEPT
+ {
+ return __sync_fetch_and_sub(&storage, v);
+ }
+
+ static BOOST_FORCEINLINE storage_type exchange(storage_type volatile& storage, storage_type v, memory_order order) BOOST_NOEXCEPT
+ {
+ // GCC docs mention that not all architectures may support full exchange semantics for this intrinsic. However, GCC's implementation of
+ // std::atomic<> uses this intrinsic unconditionally. We do so as well. In case if some architectures actually don't support this, we can always
+ // add a check here and fall back to a CAS loop.
+ if ((order & memory_order_release) != 0)
+ __sync_synchronize();
+ return __sync_lock_test_and_set(&storage, v);
+ }
+
+ static BOOST_FORCEINLINE bool compare_exchange_strong(
+ storage_type volatile& storage, storage_type& expected, storage_type desired, memory_order, memory_order) BOOST_NOEXCEPT
+ {
+ storage_type expected2 = expected;
+ storage_type old_val = __sync_val_compare_and_swap(&storage, expected2, desired);
+
+ if (old_val == expected2)
+ {
+ return true;
+ }
+ else
+ {
+ expected = old_val;
+ return false;
+ }
+ }
+
+ static BOOST_FORCEINLINE bool compare_exchange_weak(
+ storage_type volatile& storage, storage_type& expected, storage_type desired, memory_order success_order, memory_order failure_order) BOOST_NOEXCEPT
+ {
+ return compare_exchange_strong(storage, expected, desired, success_order, failure_order);
+ }
+
+ static BOOST_FORCEINLINE storage_type fetch_and(storage_type volatile& storage, storage_type v, memory_order) BOOST_NOEXCEPT
+ {
+ return __sync_fetch_and_and(&storage, v);
+ }
+
+ static BOOST_FORCEINLINE storage_type fetch_or(storage_type volatile& storage, storage_type v, memory_order) BOOST_NOEXCEPT
+ {
+ return __sync_fetch_and_or(&storage, v);
+ }
+
+ static BOOST_FORCEINLINE storage_type fetch_xor(storage_type volatile& storage, storage_type v, memory_order) BOOST_NOEXCEPT
+ {
+ return __sync_fetch_and_xor(&storage, v);
+ }
+
+ static BOOST_FORCEINLINE bool test_and_set(storage_type volatile& storage, memory_order order) BOOST_NOEXCEPT
+ {
+ if ((order & memory_order_release) != 0)
+ __sync_synchronize();
+ return !!__sync_lock_test_and_set(&storage, 1);
+ }
+
+ static BOOST_FORCEINLINE void clear(storage_type volatile& storage, memory_order order) BOOST_NOEXCEPT
+ {
+ __sync_lock_release(&storage);
+ if (order == memory_order_seq_cst)
+ __sync_synchronize();
+ }
+
+ static BOOST_FORCEINLINE bool is_lock_free(storage_type const volatile&) BOOST_NOEXCEPT
+ {
+ return true;
+ }
+};
+
+#if BOOST_ATOMIC_INT8_LOCK_FREE > 0
+template< bool Signed >
+struct operations< 1u, Signed > :
+#if defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_1)
+ public gcc_sync_operations< typename make_storage_type< 1u, Signed >::type >
+#elif defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_2)
+ public extending_cas_based_operations< gcc_sync_operations< typename make_storage_type< 2u, Signed >::type >, 1u, Signed >
+#elif defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_4)
+ public extending_cas_based_operations< gcc_sync_operations< typename make_storage_type< 4u, Signed >::type >, 1u, Signed >
+#elif defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_8)
+ public extending_cas_based_operations< gcc_sync_operations< typename make_storage_type< 8u, Signed >::type >, 1u, Signed >
+#else
+ public extending_cas_based_operations< gcc_sync_operations< typename make_storage_type< 16u, Signed >::type >, 1u, Signed >
+#endif
+{
+};
+#endif
+
+#if BOOST_ATOMIC_INT16_LOCK_FREE > 0
+template< bool Signed >
+struct operations< 2u, Signed > :
+#if defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_2)
+ public gcc_sync_operations< typename make_storage_type< 2u, Signed >::type >
+#elif defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_4)
+ public extending_cas_based_operations< gcc_sync_operations< typename make_storage_type< 4u, Signed >::type >, 2u, Signed >
+#elif defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_8)
+ public extending_cas_based_operations< gcc_sync_operations< typename make_storage_type< 8u, Signed >::type >, 2u, Signed >
+#else
+ public extending_cas_based_operations< gcc_sync_operations< typename make_storage_type< 16u, Signed >::type >, 2u, Signed >
+#endif
+{
+};
+#endif
+
+#if BOOST_ATOMIC_INT32_LOCK_FREE > 0
+template< bool Signed >
+struct operations< 4u, Signed > :
+#if defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_4)
+ public gcc_sync_operations< typename make_storage_type< 4u, Signed >::type >
+#elif defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_8)
+ public extending_cas_based_operations< gcc_sync_operations< typename make_storage_type< 8u, Signed >::type >, 4u, Signed >
+#else
+ public extending_cas_based_operations< gcc_sync_operations< typename make_storage_type< 16u, Signed >::type >, 4u, Signed >
+#endif
+{
+};
+#endif
+
+#if BOOST_ATOMIC_INT64_LOCK_FREE > 0
+template< bool Signed >
+struct operations< 8u, Signed > :
+#if defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_8)
+ public gcc_sync_operations< typename make_storage_type< 8u, Signed >::type >
+#else
+ public extending_cas_based_operations< gcc_sync_operations< typename make_storage_type< 16u, Signed >::type >, 8u, Signed >
+#endif
+{
+};
+#endif
+
+#if BOOST_ATOMIC_INT128_LOCK_FREE > 0
+template< bool Signed >
+struct operations< 16u, Signed > :
+ public gcc_sync_operations< typename make_storage_type< 16u, Signed >::type >
+{
+};
+#endif
+
+BOOST_FORCEINLINE void thread_fence(memory_order order) BOOST_NOEXCEPT
+{
+ if (order != memory_order_relaxed)
+ __sync_synchronize();
+}
+
+BOOST_FORCEINLINE void signal_fence(memory_order order) BOOST_NOEXCEPT
+{
+ if (order != memory_order_relaxed)
+ __asm__ __volatile__ ("" ::: "memory");
+}
+
+} // namespace detail
+} // namespace atomics
+} // namespace boost
+
+#endif // BOOST_ATOMIC_DETAIL_OPS_GCC_SYNC_HPP_INCLUDED_