ceph/src/boost/libs/asio/include/boost/asio/detail/gcc_arm_fenced_block.hpp

   1 //
   2 // detail/gcc_arm_fenced_block.hpp
   3 // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   4 //
   5 // Copyright (c) 2003-2016 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.
  36   explicit gcc_arm_fenced_block(half_t)
  37   {
  38   }
  39
  40   // Constructor for a full fenced block.
  41   explicit gcc_arm_fenced_block(full_t)
  42   {
  43     barrier();
  44   }
  45
  46   // Destructor.
  47   ~gcc_arm_fenced_block()
  48   {
  49     barrier();
  50   }
  51
  52 private:
  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