1 // 2 // detail/gcc_arm_fenced_block.hpp 3 // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 4 // 5 // Copyright (c) 2003-2019 Christopher M. Kohlhoff (chris at kohlhoff dot com) 6 // 7 // Distributed under the Boost Software License, Version 1.0. (See accompanying 8 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) 9 // 10 11 #ifndef BOOST_ASIO_DETAIL_GCC_ARM_FENCED_BLOCK_HPP 12 #define BOOST_ASIO_DETAIL_GCC_ARM_FENCED_BLOCK_HPP 13 14 #if defined(_MSC_VER) && (_MSC_VER >= 1200) 15 # pragma once 16 #endif // defined(_MSC_VER) && (_MSC_VER >= 1200) 17 18 #include <boost/asio/detail/config.hpp> 19 20 #if defined(__GNUC__) && defined(__arm__) 21 22 #include <boost/asio/detail/noncopyable.hpp> 23 24 #include <boost/asio/detail/push_options.hpp> 25 26 namespace boost { 27 namespace asio { 28 namespace detail { 29 30 class gcc_arm_fenced_block 31 : private noncopyable 32 { 33 public: 34 enum half_t { half }; 35 enum full_t { full }; 36 37 // Constructor for a half fenced block. gcc_arm_fenced_block(half_t)38 explicit gcc_arm_fenced_block(half_t) 39 { 40 } 41 42 // Constructor for a full fenced block. gcc_arm_fenced_block(full_t)43 explicit gcc_arm_fenced_block(full_t) 44 { 45 barrier(); 46 } 47 48 // Destructor. ~gcc_arm_fenced_block()49 ~gcc_arm_fenced_block() 50 { 51 barrier(); 52 } 53 54 private: barrier()55 static void barrier() 56 { 57 #if defined(__ARM_ARCH_4__) \ 58 || defined(__ARM_ARCH_4T__) \ 59 || defined(__ARM_ARCH_5__) \ 60 || defined(__ARM_ARCH_5E__) \ 61 || defined(__ARM_ARCH_5T__) \ 62 || defined(__ARM_ARCH_5TE__) \ 63 || defined(__ARM_ARCH_5TEJ__) \ 64 || defined(__ARM_ARCH_6__) \ 65 || defined(__ARM_ARCH_6J__) \ 66 || defined(__ARM_ARCH_6K__) \ 67 || defined(__ARM_ARCH_6Z__) \ 68 || defined(__ARM_ARCH_6ZK__) \ 69 || defined(__ARM_ARCH_6T2__) 70 # if defined(__thumb__) 71 // This is just a placeholder and almost certainly not sufficient. 72 __asm__ __volatile__ ("" : : : "memory"); 73 # else // defined(__thumb__) 74 int a = 0, b = 0; 75 __asm__ __volatile__ ("swp %0, %1, [%2]" 76 : "=&r"(a) : "r"(1), "r"(&b) : "memory", "cc"); 77 # endif // defined(__thumb__) 78 #else 79 // ARMv7 and later. 80 __asm__ __volatile__ ("dmb" : : : "memory"); 81 #endif 82 } 83 }; 84 85 } // namespace detail 86 } // namespace asio 87 } // namespace boost 88 89 #include <boost/asio/detail/pop_options.hpp> 90 91 #endif // defined(__GNUC__) && defined(__arm__) 92 93 #endif // BOOST_ASIO_DETAIL_GCC_ARM_FENCED_BLOCK_HPP 94