ceph/src/boost/boost/atomic/detail/pause.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  * (C) Copyright 2013 Tim Blechmann
   7  * (C) Copyright 2013, 2020 Andrey Semashev
   8  */
   9
  10 #ifndef BOOST_ATOMIC_DETAIL_PAUSE_HPP_INCLUDED_
  11 #define BOOST_ATOMIC_DETAIL_PAUSE_HPP_INCLUDED_
  12
  13 #include <boost/atomic/detail/config.hpp>
  14 #include <boost/atomic/detail/header.hpp>
  15
  16 #ifdef BOOST_HAS_PRAGMA_ONCE
  17 #pragma once
  18 #endif
  19
  20 #if defined(_MSC_VER)
  21 #if defined(_M_AMD64) || defined(_M_IX86)
  22 extern "C" void _mm_pause(void);
  23 #if defined(BOOST_MSVC)
  24 #pragma intrinsic(_mm_pause)
  25 #endif
  26 #elif defined(_M_ARM64) || defined(_M_ARM)
  27 extern "C" void __yield(void);
  28 #if defined(BOOST_MSVC)
  29 #pragma intrinsic(__yield)
  30 #endif
  31 #endif
  32 #endif
  33
  34 namespace boost {
  35 namespace atomics {
  36 namespace detail {
  37
  38 BOOST_FORCEINLINE void pause() BOOST_NOEXCEPT
  39 {
  40 #if defined(_MSC_VER)
  41 #if defined(_M_AMD64) || defined(_M_IX86)
  42     _mm_pause();
  43 #elif defined(_M_ARM64) || defined(_M_ARM)
  44     __yield();
  45 #endif
  46 #elif defined(__GNUC__)
  47 #if defined(__i386__) || defined(__x86_64__)
  48     __asm__ __volatile__("pause;" : : : "memory");
  49 #elif (defined(__ARM_ARCH) && __ARM_ARCH >= 8) || defined(__ARM_ARCH_8A__) || defined(__aarch64__)
  50     __asm__ __volatile__("yield;" : : : "memory");
  51 #endif
  52 #endif
  53 }
  54
  55 } // namespace detail
  56 } // namespace atomics
  57 } // namespace boost
  58
  59 #include <boost/atomic/detail/footer.hpp>
  60
  61 #endif // BOOST_ATOMIC_DETAIL_PAUSE_HPP_INCLUDED_