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//
// detail/gcc_arm_fenced_block.hpp
// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
//
// Copyright (c) 2003-2018 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 ASIO_DETAIL_GCC_ARM_FENCED_BLOCK_HPP
#define ASIO_DETAIL_GCC_ARM_FENCED_BLOCK_HPP
#if defined(_MSC_VER) && (_MSC_VER >= 1200)
# pragma once
#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
#include "asio/detail/config.hpp"
#if defined(__GNUC__) && defined(__arm__)
#include "asio/detail/noncopyable.hpp"
#include "asio/detail/push_options.hpp"
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
#include "asio/detail/pop_options.hpp"
#endif // defined(__GNUC__) && defined(__arm__)
#endif // ASIO_DETAIL_GCC_ARM_FENCED_BLOCK_HPP
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