ceph/src/boost/boost/atomic/detail/fp_ops_emulated.hpp

   1 /*
   2  * Distributed under the Boost Software License, Version 1.0.
   3  * (See accompanying file LICENSE_1_0.txt or copy at
   4  * http://www.boost.org/LICENSE_1_0.txt)
   5  *
   6  * Copyright (c) 2018 Andrey Semashev
   7  */
   8 /*!
   9  * \file   atomic/detail/fp_ops_emulated.hpp
  10  *
  11  * This header contains emulated (lock-based) implementation of the floating point atomic operations.
  12  */
  13
  14 #ifndef BOOST_ATOMIC_DETAIL_FP_OPS_EMULATED_HPP_INCLUDED_
  15 #define BOOST_ATOMIC_DETAIL_FP_OPS_EMULATED_HPP_INCLUDED_
  16
  17 #include <cstddef>
  18 #include <boost/memory_order.hpp>
  19 #include <boost/atomic/detail/config.hpp>
  20 #include <boost/atomic/detail/bitwise_fp_cast.hpp>
  21 #include <boost/atomic/detail/fp_operations_fwd.hpp>
  22 #include <boost/atomic/detail/lockpool.hpp>
  23
  24 #ifdef BOOST_HAS_PRAGMA_ONCE
  25 #pragma once
  26 #endif
  27
  28 namespace boost {
  29 namespace atomics {
  30 namespace detail {
  31
  32 //! Generic implementation of floating point operations
  33 template< typename Base, typename Value, std::size_t Size >
  34 struct emulated_fp_operations :
  35     public Base
  36 {
  37     typedef Base base_type;
  38     typedef typename base_type::storage_type storage_type;
  39     typedef Value value_type;
  40
  41     static BOOST_FORCEINLINE value_type fetch_add(storage_type volatile& storage, value_type v, memory_order) BOOST_NOEXCEPT
  42     {
  43         storage_type& s = const_cast< storage_type& >(storage);
  44         lockpool::scoped_lock lock(&storage);
  45         value_type old_val = atomics::detail::bitwise_fp_cast< value_type >(s);
  46         value_type new_val = old_val + v;
  47         s = atomics::detail::bitwise_fp_cast< storage_type >(new_val);
  48         return old_val;
  49     }
  50
  51     static BOOST_FORCEINLINE value_type fetch_sub(storage_type volatile& storage, value_type v, memory_order) BOOST_NOEXCEPT
  52     {
  53         storage_type& s = const_cast< storage_type& >(storage);
  54         lockpool::scoped_lock lock(&storage);
  55         value_type old_val = atomics::detail::bitwise_fp_cast< value_type >(s);
  56         value_type new_val = old_val - v;
  57         s = atomics::detail::bitwise_fp_cast< storage_type >(new_val);
  58         return old_val;
  59     }
  60 };
  61
  62 template< typename Base, typename Value, std::size_t Size >
  63 struct fp_operations< Base, Value, Size, false > :
  64     public emulated_fp_operations< Base, Value, Size >
  65 {
  66 };
  67
  68 } // namespace detail
  69 } // namespace atomics
  70 } // namespace boost
  71
  72 #endif // BOOST_ATOMIC_DETAIL_FP_OPS_EMULATED_HPP_INCLUDED_