summaryrefslogtreecommitdiff
path: root/boost/asio/detail/gcc_arm_fenced_block.hpp
blob: 3a5a1dfacf9bfcf18b36ab5cece7158531906213 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
//
// 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 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