1 // 2 // detail/gcc_arm_fenced_block.hpp 3 // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 4 // 5 // Copyright (c) 2003-2015 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/push_options.hpp> 23 24 namespace boost { 25 namespace asio { 26 namespace detail { 27 28 class gcc_arm_fenced_block 29 : private noncopyable 30 { 31 public: 32 enum half_t { half }; 33 enum full_t { full }; 34 35 // Constructor for a half fenced block. gcc_arm_fenced_block(half_t)36 explicit gcc_arm_fenced_block(half_t) 37 { 38 } 39 40 // Constructor for a full fenced block. gcc_arm_fenced_block(full_t)41 explicit gcc_arm_fenced_block(full_t) 42 { 43 barrier(); 44 } 45 46 // Destructor. ~gcc_arm_fenced_block()47 ~gcc_arm_fenced_block() 48 { 49 barrier(); 50 } 51 52 private: barrier()53 static void barrier() 54 { 55 #if defined(__ARM_ARCH_4__) \ 56 || defined(__ARM_ARCH_4T__) \ 57 || defined(__ARM_ARCH_5__) \ 58 || defined(__ARM_ARCH_5E__) \ 59 || defined(__ARM_ARCH_5T__) \ 60 || defined(__ARM_ARCH_5TE__) \ 61 || defined(__ARM_ARCH_5TEJ__) \ 62 || defined(__ARM_ARCH_6__) \ 63 || defined(__ARM_ARCH_6J__) \ 64 || defined(__ARM_ARCH_6K__) \ 65 || defined(__ARM_ARCH_6Z__) \ 66 || defined(__ARM_ARCH_6ZK__) \ 67 || defined(__ARM_ARCH_6T2__) 68 # if defined(__thumb__) 69 // This is just a placeholder and almost certainly not sufficient. 70 __asm__ __volatile__ ("" : : : "memory"); 71 # else // defined(__thumb__) 72 int a = 0, b = 0; 73 __asm__ __volatile__ ("swp %0, %1, [%2]" 74 : "=&r"(a) : "r"(1), "r"(&b) : "memory", "cc"); 75 # endif // defined(__thumb__) 76 #else 77 // ARMv7 and later. 78 __asm__ __volatile__ ("dmb" : : : "memory"); 79 #endif 80 } 81 }; 82 83 } // namespace detail 84 } // namespace asio 85 } // namespace boost 86 87 #include <boost/asio/detail/pop_options.hpp> 88 89 #endif // defined(__GNUC__) && defined(__arm__) 90 91 #endif // BOOST_ASIO_DETAIL_GCC_ARM_FENCED_BLOCK_HPP 92