1 /* 2 * Distributed under the Boost Software License, Version 1.0. 3 * (See accompanying file LICENSE_1_0.txt or copy at 4 * http://www.boost.org/LICENSE_1_0.txt) 5 * 6 * Copyright (c) 2020 Andrey Semashev 7 */ 8 /*! 9 * \file atomic/detail/fence_arch_ops_msvc_x86.hpp 10 * 11 * This header contains implementation of the \c fence_arch_operations struct. 12 */ 13 14 #ifndef BOOST_ATOMIC_DETAIL_FENCE_ARCH_OPS_MSVC_X86_HPP_INCLUDED_ 15 #define BOOST_ATOMIC_DETAIL_FENCE_ARCH_OPS_MSVC_X86_HPP_INCLUDED_ 16 17 #include <boost/cstdint.hpp> 18 #include <boost/memory_order.hpp> 19 #include <boost/atomic/detail/config.hpp> 20 #include <boost/atomic/detail/interlocked.hpp> 21 #include <boost/atomic/detail/ops_msvc_common.hpp> 22 #include <boost/atomic/detail/header.hpp> 23 24 #ifdef BOOST_HAS_PRAGMA_ONCE 25 #pragma once 26 #endif 27 28 namespace boost { 29 namespace atomics { 30 namespace detail { 31 32 //! Fence operations for x86 33 struct fence_arch_operations_msvc_x86 34 { thread_fenceboost::atomics::detail::fence_arch_operations_msvc_x8635 static BOOST_FORCEINLINE void thread_fence(memory_order order) BOOST_NOEXCEPT 36 { 37 if (order == memory_order_seq_cst) 38 { 39 // See the comment in fence_ops_gcc_x86.hpp as to why we're not using mfence here. 40 // We're not using __faststorefence() here because it generates an atomic operation 41 // on [rsp]/[esp] location, which may alias valid data and cause false data dependency. 42 boost::uint32_t dummy; 43 BOOST_ATOMIC_INTERLOCKED_INCREMENT(&dummy); 44 } 45 else if (order != memory_order_relaxed) 46 { 47 BOOST_ATOMIC_DETAIL_COMPILER_BARRIER(); 48 } 49 } 50 signal_fenceboost::atomics::detail::fence_arch_operations_msvc_x8651 static BOOST_FORCEINLINE void signal_fence(memory_order order) BOOST_NOEXCEPT 52 { 53 if (order != memory_order_relaxed) 54 BOOST_ATOMIC_DETAIL_COMPILER_BARRIER(); 55 } 56 }; 57 58 typedef fence_arch_operations_msvc_x86 fence_arch_operations; 59 60 } // namespace detail 61 } // namespace atomics 62 } // namespace boost 63 64 #include <boost/atomic/detail/footer.hpp> 65 66 #endif // BOOST_ATOMIC_DETAIL_FENCE_ARCH_OPS_MSVC_X86_HPP_INCLUDED_ 67