/*

 * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 *

 */

#include <intrin.h>

// Compiler version last used for testing: Microsoft Visual Studio 2010

// Please update this information when this file changes

// Implementation of class OrderAccess.

// A compiler barrier, forcing the C++ compiler to invalidate all memory assumptions

inline void compiler_barrier() {

  _ReadWriteBarrier();

}

// Note that in MSVC, volatile memory accesses are explicitly

// guaranteed to have acquire release semantics (w.r.t. compiler

// reordering) and therefore does not even need a compiler barrier

// for normal acquire release accesses. And all generalized

// bound calls like release_store go through OrderAccess::load

// and OrderAccess::store which do volatile memory accesses.

template<> inline void ScopedFence<X_ACQUIRE>::postfix()       { }

template<> inline void ScopedFence<RELEASE_X>::prefix()        { }

template<> inline void ScopedFence<RELEASE_X_FENCE>::prefix()  { }

template<> inline void ScopedFence<RELEASE_X_FENCE>::postfix() { OrderAccess::fence(); }

inline void OrderAccess::loadload()   { compiler_barrier(); }

inline void OrderAccess::storestore() { compiler_barrier(); }

inline void OrderAccess::loadstore()  { compiler_barrier(); }

inline void OrderAccess::storeload()  { fence(); }

inline void OrderAccess::acquire()    { compiler_barrier(); }

inline void OrderAccess::release()    { compiler_barrier(); }

inline void OrderAccess::fence() {

#ifdef AMD64

  StubRoutines_fence();

#else

  }

#endif // AMD64

  compiler_barrier();

}

#ifndef AMD64

template<>

struct OrderAccess::PlatformOrderedStore<1, RELEASE_X_FENCE>

{

  template <typename T>

  void operator()(T v, volatile T* p) const {

    __asm {

      mov edx, p;

      mov al, v;

      xchg al, byte ptr [edx];

    }

  }

};

template<>

struct OrderAccess::PlatformOrderedStore<2, RELEASE_X_FENCE>

{

  template <typename T>

  void operator()(T v, volatile T* p) const {

    __asm {

      mov edx, p;

      mov ax, v;

      xchg ax, word ptr [edx];

    }

  }

};

template<>

struct OrderAccess::PlatformOrderedStore<4, RELEASE_X_FENCE>

{

  template <typename T>

  void operator()(T v, volatile T* p) const {

    __asm {

      mov edx, p;

      mov eax, v;

      xchg eax, dword ptr [edx];

    }

  }

};

#endif // AMD64