Chris@102: /*
Chris@102:  * Distributed under the Boost Software License, Version 1.0.
Chris@102:  * (See accompanying file LICENSE_1_0.txt or copy at
Chris@102:  * http://www.boost.org/LICENSE_1_0.txt)
Chris@102:  *
Chris@102:  * Copyright (c) 2011 Helge Bahmann
Chris@102:  * Copyright (c) 2013 Tim Blechmann
Chris@102:  * Copyright (c) 2014 Andrey Semashev
Chris@102:  */
Chris@102: /*!
Chris@102:  * \file   atomic/detail/ops_gcc_sync.hpp
Chris@102:  *
Chris@102:  * This header contains implementation of the \c operations template.
Chris@102:  */
Chris@102: 
Chris@102: #ifndef BOOST_ATOMIC_DETAIL_OPS_GCC_SYNC_HPP_INCLUDED_
Chris@102: #define BOOST_ATOMIC_DETAIL_OPS_GCC_SYNC_HPP_INCLUDED_
Chris@102: 
Chris@102: #include <boost/memory_order.hpp>
Chris@102: #include <boost/atomic/detail/config.hpp>
Chris@102: #include <boost/atomic/detail/storage_type.hpp>
Chris@102: #include <boost/atomic/detail/operations_fwd.hpp>
Chris@102: #include <boost/atomic/detail/ops_extending_cas_based.hpp>
Chris@102: #include <boost/atomic/capabilities.hpp>
Chris@102: 
Chris@102: #ifdef BOOST_HAS_PRAGMA_ONCE
Chris@102: #pragma once
Chris@102: #endif
Chris@102: 
Chris@102: namespace boost {
Chris@102: namespace atomics {
Chris@102: namespace detail {
Chris@102: 
Chris@102: struct gcc_sync_operations_base
Chris@102: {
Chris@102:     static BOOST_FORCEINLINE void fence_before_store(memory_order order) BOOST_NOEXCEPT
Chris@102:     {
Chris@102:         if ((order & memory_order_release) != 0)
Chris@102:             __sync_synchronize();
Chris@102:     }
Chris@102: 
Chris@102:     static BOOST_FORCEINLINE void fence_after_store(memory_order order) BOOST_NOEXCEPT
Chris@102:     {
Chris@102:         if (order == memory_order_seq_cst)
Chris@102:             __sync_synchronize();
Chris@102:     }
Chris@102: 
Chris@102:     static BOOST_FORCEINLINE void fence_after_load(memory_order order) BOOST_NOEXCEPT
Chris@102:     {
Chris@102:         if ((order & (memory_order_acquire | memory_order_consume)) != 0)
Chris@102:             __sync_synchronize();
Chris@102:     }
Chris@102: };
Chris@102: 
Chris@102: template< typename T >
Chris@102: struct gcc_sync_operations :
Chris@102:     public gcc_sync_operations_base
Chris@102: {
Chris@102:     typedef T storage_type;
Chris@102: 
Chris@102:     static BOOST_FORCEINLINE void store(storage_type volatile& storage, storage_type v, memory_order order) BOOST_NOEXCEPT
Chris@102:     {
Chris@102:         fence_before_store(order);
Chris@102:         storage = v;
Chris@102:         fence_after_store(order);
Chris@102:     }
Chris@102: 
Chris@102:     static BOOST_FORCEINLINE storage_type load(storage_type const volatile& storage, memory_order order) BOOST_NOEXCEPT
Chris@102:     {
Chris@102:         storage_type v = storage;
Chris@102:         fence_after_load(order);
Chris@102:         return v;
Chris@102:     }
Chris@102: 
Chris@102:     static BOOST_FORCEINLINE storage_type fetch_add(storage_type volatile& storage, storage_type v, memory_order) BOOST_NOEXCEPT
Chris@102:     {
Chris@102:         return __sync_fetch_and_add(&storage, v);
Chris@102:     }
Chris@102: 
Chris@102:     static BOOST_FORCEINLINE storage_type fetch_sub(storage_type volatile& storage, storage_type v, memory_order) BOOST_NOEXCEPT
Chris@102:     {
Chris@102:         return __sync_fetch_and_sub(&storage, v);
Chris@102:     }
Chris@102: 
Chris@102:     static BOOST_FORCEINLINE storage_type exchange(storage_type volatile& storage, storage_type v, memory_order order) BOOST_NOEXCEPT
Chris@102:     {
Chris@102:         // GCC docs mention that not all architectures may support full exchange semantics for this intrinsic. However, GCC's implementation of
Chris@102:         // std::atomic<> uses this intrinsic unconditionally. We do so as well. In case if some architectures actually don't support this, we can always
Chris@102:         // add a check here and fall back to a CAS loop.
Chris@102:         if ((order & memory_order_release) != 0)
Chris@102:             __sync_synchronize();
Chris@102:         return __sync_lock_test_and_set(&storage, v);
Chris@102:     }
Chris@102: 
Chris@102:     static BOOST_FORCEINLINE bool compare_exchange_strong(
Chris@102:         storage_type volatile& storage, storage_type& expected, storage_type desired, memory_order, memory_order) BOOST_NOEXCEPT
Chris@102:     {
Chris@102:         storage_type expected2 = expected;
Chris@102:         storage_type old_val = __sync_val_compare_and_swap(&storage, expected2, desired);
Chris@102: 
Chris@102:         if (old_val == expected2)
Chris@102:         {
Chris@102:             return true;
Chris@102:         }
Chris@102:         else
Chris@102:         {
Chris@102:             expected = old_val;
Chris@102:             return false;
Chris@102:         }
Chris@102:     }
Chris@102: 
Chris@102:     static BOOST_FORCEINLINE bool compare_exchange_weak(
Chris@102:         storage_type volatile& storage, storage_type& expected, storage_type desired, memory_order success_order, memory_order failure_order) BOOST_NOEXCEPT
Chris@102:     {
Chris@102:         return compare_exchange_strong(storage, expected, desired, success_order, failure_order);
Chris@102:     }
Chris@102: 
Chris@102:     static BOOST_FORCEINLINE storage_type fetch_and(storage_type volatile& storage, storage_type v, memory_order) BOOST_NOEXCEPT
Chris@102:     {
Chris@102:         return __sync_fetch_and_and(&storage, v);
Chris@102:     }
Chris@102: 
Chris@102:     static BOOST_FORCEINLINE storage_type fetch_or(storage_type volatile& storage, storage_type v, memory_order) BOOST_NOEXCEPT
Chris@102:     {
Chris@102:         return __sync_fetch_and_or(&storage, v);
Chris@102:     }
Chris@102: 
Chris@102:     static BOOST_FORCEINLINE storage_type fetch_xor(storage_type volatile& storage, storage_type v, memory_order) BOOST_NOEXCEPT
Chris@102:     {
Chris@102:         return __sync_fetch_and_xor(&storage, v);
Chris@102:     }
Chris@102: 
Chris@102:     static BOOST_FORCEINLINE bool test_and_set(storage_type volatile& storage, memory_order order) BOOST_NOEXCEPT
Chris@102:     {
Chris@102:         if ((order & memory_order_release) != 0)
Chris@102:             __sync_synchronize();
Chris@102:         return !!__sync_lock_test_and_set(&storage, 1);
Chris@102:     }
Chris@102: 
Chris@102:     static BOOST_FORCEINLINE void clear(storage_type volatile& storage, memory_order order) BOOST_NOEXCEPT
Chris@102:     {
Chris@102:         __sync_lock_release(&storage);
Chris@102:         if (order == memory_order_seq_cst)
Chris@102:             __sync_synchronize();
Chris@102:     }
Chris@102: 
Chris@102:     static BOOST_FORCEINLINE bool is_lock_free(storage_type const volatile&) BOOST_NOEXCEPT
Chris@102:     {
Chris@102:         return true;
Chris@102:     }
Chris@102: };
Chris@102: 
Chris@102: #if BOOST_ATOMIC_INT8_LOCK_FREE > 0
Chris@102: template< bool Signed >
Chris@102: struct operations< 1u, Signed > :
Chris@102: #if defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_1)
Chris@102:     public gcc_sync_operations< typename make_storage_type< 1u, Signed >::type >
Chris@102: #elif defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_2)
Chris@102:     public extending_cas_based_operations< gcc_sync_operations< typename make_storage_type< 2u, Signed >::type >, 1u, Signed >
Chris@102: #elif defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_4)
Chris@102:     public extending_cas_based_operations< gcc_sync_operations< typename make_storage_type< 4u, Signed >::type >, 1u, Signed >
Chris@102: #elif defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_8)
Chris@102:     public extending_cas_based_operations< gcc_sync_operations< typename make_storage_type< 8u, Signed >::type >, 1u, Signed >
Chris@102: #else
Chris@102:     public extending_cas_based_operations< gcc_sync_operations< typename make_storage_type< 16u, Signed >::type >, 1u, Signed >
Chris@102: #endif
Chris@102: {
Chris@102: };
Chris@102: #endif
Chris@102: 
Chris@102: #if BOOST_ATOMIC_INT16_LOCK_FREE > 0
Chris@102: template< bool Signed >
Chris@102: struct operations< 2u, Signed > :
Chris@102: #if defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_2)
Chris@102:     public gcc_sync_operations< typename make_storage_type< 2u, Signed >::type >
Chris@102: #elif defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_4)
Chris@102:     public extending_cas_based_operations< gcc_sync_operations< typename make_storage_type< 4u, Signed >::type >, 2u, Signed >
Chris@102: #elif defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_8)
Chris@102:     public extending_cas_based_operations< gcc_sync_operations< typename make_storage_type< 8u, Signed >::type >, 2u, Signed >
Chris@102: #else
Chris@102:     public extending_cas_based_operations< gcc_sync_operations< typename make_storage_type< 16u, Signed >::type >, 2u, Signed >
Chris@102: #endif
Chris@102: {
Chris@102: };
Chris@102: #endif
Chris@102: 
Chris@102: #if BOOST_ATOMIC_INT32_LOCK_FREE > 0
Chris@102: template< bool Signed >
Chris@102: struct operations< 4u, Signed > :
Chris@102: #if defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_4)
Chris@102:     public gcc_sync_operations< typename make_storage_type< 4u, Signed >::type >
Chris@102: #elif defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_8)
Chris@102:     public extending_cas_based_operations< gcc_sync_operations< typename make_storage_type< 8u, Signed >::type >, 4u, Signed >
Chris@102: #else
Chris@102:     public extending_cas_based_operations< gcc_sync_operations< typename make_storage_type< 16u, Signed >::type >, 4u, Signed >
Chris@102: #endif
Chris@102: {
Chris@102: };
Chris@102: #endif
Chris@102: 
Chris@102: #if BOOST_ATOMIC_INT64_LOCK_FREE > 0
Chris@102: template< bool Signed >
Chris@102: struct operations< 8u, Signed > :
Chris@102: #if defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_8)
Chris@102:     public gcc_sync_operations< typename make_storage_type< 8u, Signed >::type >
Chris@102: #else
Chris@102:     public extending_cas_based_operations< gcc_sync_operations< typename make_storage_type< 16u, Signed >::type >, 8u, Signed >
Chris@102: #endif
Chris@102: {
Chris@102: };
Chris@102: #endif
Chris@102: 
Chris@102: #if BOOST_ATOMIC_INT128_LOCK_FREE > 0
Chris@102: template< bool Signed >
Chris@102: struct operations< 16u, Signed > :
Chris@102:     public gcc_sync_operations< typename make_storage_type< 16u, Signed >::type >
Chris@102: {
Chris@102: };
Chris@102: #endif
Chris@102: 
Chris@102: BOOST_FORCEINLINE void thread_fence(memory_order order) BOOST_NOEXCEPT
Chris@102: {
Chris@102:     if (order != memory_order_relaxed)
Chris@102:         __sync_synchronize();
Chris@102: }
Chris@102: 
Chris@102: BOOST_FORCEINLINE void signal_fence(memory_order order) BOOST_NOEXCEPT
Chris@102: {
Chris@102:     if (order != memory_order_relaxed)
Chris@102:         __asm__ __volatile__ ("" ::: "memory");
Chris@102: }
Chris@102: 
Chris@102: } // namespace detail
Chris@102: } // namespace atomics
Chris@102: } // namespace boost
Chris@102: 
Chris@102: #endif // BOOST_ATOMIC_DETAIL_OPS_GCC_SYNC_HPP_INCLUDED_