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- //
- // detail/gcc_arm_fenced_block.hpp
- // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
- //
- // Copyright (c) 2003-2019 Christopher M. Kohlhoff (chris at kohlhoff dot com)
- //
- // Distributed under the Boost Software License, Version 1.0. (See accompanying
- // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
- //
- #ifndef BOOST_ASIO_DETAIL_GCC_ARM_FENCED_BLOCK_HPP
- #define BOOST_ASIO_DETAIL_GCC_ARM_FENCED_BLOCK_HPP
- #if defined(_MSC_VER) && (_MSC_VER >= 1200)
- # pragma once
- #endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
- #include <boost/asio/detail/config.hpp>
- #if defined(__GNUC__) && defined(__arm__)
- #include <boost/asio/detail/noncopyable.hpp>
- #include <boost/asio/detail/push_options.hpp>
- namespace boost {
- namespace asio {
- namespace detail {
- class gcc_arm_fenced_block
- : private noncopyable
- {
- public:
- enum half_t { half };
- enum full_t { full };
- // Constructor for a half fenced block.
- explicit gcc_arm_fenced_block(half_t)
- {
- }
- // Constructor for a full fenced block.
- explicit gcc_arm_fenced_block(full_t)
- {
- barrier();
- }
- // Destructor.
- ~gcc_arm_fenced_block()
- {
- barrier();
- }
- private:
- static void barrier()
- {
- #if defined(__ARM_ARCH_4__) \
- || defined(__ARM_ARCH_4T__) \
- || defined(__ARM_ARCH_5__) \
- || defined(__ARM_ARCH_5E__) \
- || defined(__ARM_ARCH_5T__) \
- || defined(__ARM_ARCH_5TE__) \
- || defined(__ARM_ARCH_5TEJ__) \
- || defined(__ARM_ARCH_6__) \
- || defined(__ARM_ARCH_6J__) \
- || defined(__ARM_ARCH_6K__) \
- || defined(__ARM_ARCH_6Z__) \
- || defined(__ARM_ARCH_6ZK__) \
- || defined(__ARM_ARCH_6T2__)
- # if defined(__thumb__)
- // This is just a placeholder and almost certainly not sufficient.
- __asm__ __volatile__ ("" : : : "memory");
- # else // defined(__thumb__)
- int a = 0, b = 0;
- __asm__ __volatile__ ("swp %0, %1, [%2]"
- : "=&r"(a) : "r"(1), "r"(&b) : "memory", "cc");
- # endif // defined(__thumb__)
- #else
- // ARMv7 and later.
- __asm__ __volatile__ ("dmb" : : : "memory");
- #endif
- }
- };
- } // namespace detail
- } // namespace asio
- } // namespace boost
- #include <boost/asio/detail/pop_options.hpp>
- #endif // defined(__GNUC__) && defined(__arm__)
- #endif // BOOST_ASIO_DETAIL_GCC_ARM_FENCED_BLOCK_HPP
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