/*BEGIN_LEGAL 
Intel Open Source License 

Copyright (c) 2002-2013 Intel Corporation. All rights reserved.
 
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:

Redistributions of source code must retain the above copyright notice,
this list of conditions and the following disclaimer.  Redistributions
in binary form must reproduce the above copyright notice, this list of
conditions and the following disclaimer in the documentation and/or
other materials provided with the distribution.  Neither the name of
the Intel Corporation nor the names of its contributors may be used to
endorse or promote products derived from this software without
specific prior written permission.
 
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE INTEL OR
ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
END_LEGAL */
// <ORIGINAL-AUTHOR>: Greg Lueck
// <COMPONENT>: atomic
// <FILE-TYPE>: component public header

#ifndef ATOMIC_OPS_HPP
#define ATOMIC_OPS_HPP

#include "fund.hpp"
#include "atomic/exponential-backoff.hpp"
#include "atomic/ops-enum.hpp"
#include "atomic/private/ops-common-impl.hpp"
#include "atomic/private/backoff-impl.hpp"

#if defined(FUND_HOST_IA32)
#   include "atomic/private/ia32/ops-impl.hpp"
#elif defined(FUND_HOST_INTEL64) || defined(FUND_HOST_MIC)
#   include "atomic/private/intel64/ops-impl.hpp"
#elif defined(FUND_HOST_IA64)
#   include "atomic/private/ia64/ops-impl.hpp"
#endif


namespace ATOMIC {


/*! @brief  Low-level atomic memory operations.
 *
 * A collection of low-level atomic memory operations that can be performed on fundemental data types
 * (integers, pointers, etc.)  All of the operations are static template methods, so they automatically
 * adapt to whatever data type you use.
 *
 * @par Example:
 *                                                                                          \code
 *  #include "atomic/ops.hpp"
 *
 *  int Count;
 *
 *  void Foo()
 *  {
 *      ATOMIC::OPS::Increment(&Count, 1);
 *  }
 *                                                                                          \endcode
 */
class /*<UTILITY>*/ OPS
{
  public:
    /*!
     * Perform an atomic compare-and-swap.
     *
     *  @param[in] location     Pointer to the location to modify.
     *  @param[in] oldVal       The \a location is only changed if its value is
     *                           equal to \a oldVal.
     *  @param[in] newVal       The new value to write to \a location.
     *  @param[in] barrier      Tells the memory ordering semantics of this operation.
     *
     * @return  The value of \a location prior to the operation.  The \a newVal was stored
     *           only if the return value is equal to \a oldVal.
     */
    template<typename T> static T CompareAndSwap(volatile T *location, T oldVal, T newVal,
        BARRIER_CS barrier = BARRIER_CS_NONE)
    {
        OPS_IMPL::CompareAndSwap<sizeof(T)>(static_cast<volatile void*>(location),
            static_cast<const void*>(&oldVal), static_cast<void*>(&newVal), barrier);
        return newVal;
    }

    /*!
     * This is exactly the same as CompareAndSwap() except the return value is a
     * boolean.
     *
     *  @param[in] location     Pointer to the location to modify.
     *  @param[in] oldVal       The \a location is only changed if its value is
     *                           equal to \a oldVal.
     *  @param[in] newVal       The new value to write to \a location.
     *  @param[in] barrier      Tells the memory ordering semantics of this operation.
     *
     * @return  TRUE if \a newVal was stored to \a location.
     */
    template<typename T> static bool CompareAndDidSwap(volatile T *location, T oldVal, T newVal,
        BARRIER_CS barrier = BARRIER_CS_NONE)
    {
        OPS_IMPL::CompareAndSwap<sizeof(T)>(static_cast<volatile void*>(location),
            static_cast<const void*>(&oldVal), static_cast<void*>(&newVal), barrier);
        return (newVal == oldVal);
    }

    /*!
     * Perform an atomic swap.
     *
     *  @param[in]  location     Pointer to the location to modify.
     *  @param[in]  newVal       The new value to write to \a location.
     *  @param[in]  barrier      Tells the memory ordering semantics of this operation.
     *
     * @return  The value swapped out of \a location
     */
    template<typename T> static T Swap(volatile T *location, T  newVal,
        BARRIER_SWAP barrier = BARRIER_SWAP_NONE)
    {
        T oldVal;
        
        OPS_IMPL::Swap<sizeof(T)>(static_cast<volatile void*>(location),
            static_cast<void*>(&oldVal),
            static_cast<const void*>(&newVal),
            barrier);

        return oldVal;
    }

    /*!
     * Atomically set the value of a location.  Any outside observer using an OPS method
     * is guaranteed to see either the old value or the new value (but not an intermediate value).
     *
     *  @param[in] location     Pointer to the location.
     *  @param[in] val          The value to write to \a location.
     *  @param[in] barrier      Tells the memory ordering semantics of this operation.
     */
    template<typename T> static void Store(volatile T *location, T val, BARRIER_ST barrier = BARRIER_ST_NONE)
    {
        OPS_IMPL::Store<sizeof(T)>(static_cast<volatile void*>(location), static_cast<const void*>(&val), barrier);
    }

    /*!
     * Atomically get the value of a location.  If another thread changes the location using an
     * OPS method, Load() is guaranteed to either return the old value or the new value (but not
     * an intermediate value).
     *
     *  @param[in] location     Pointer to the location.
     *  @param[in] barrier      Tells the memory ordering semantics of this operation.
     *
     * @return  The value at \a location.
     */
    template<typename T> static T Load(volatile const T *location, BARRIER_LD barrier = BARRIER_LD_NONE)
    {
        T val;
        OPS_IMPL::Load<sizeof(T)>(static_cast<volatile const void*>(location), static_cast<void*>(&val), barrier);
        return val;
    }

    /*!
     * Atomically increment a value.
     *
     *  @param[in] location   Pointer to the location to modify.
     *  @param[in] inc        The increment amount.
     *  @param[in] barrier    Tells the memory ordering semantics of this operation.
     *
     * @return  The value of \a location prior to being incremented.
     */
    template<typename T> static T Increment(volatile T *location, T inc,
        BARRIER_CS barrier = BARRIER_CS_NONE)
    {
        T oldVal;
        OPS_IMPL::Increment<sizeof(T)>(static_cast<volatile void*>(location), static_cast<const void*>(&inc),
            static_cast<void*>(&oldVal), barrier);
        return oldVal;
    }

    /*!
     * Atomically set a location if it is less than a value.  This allows you to
     * compute the maximum of a series of values.
     *
     *  @param[in] location   Pointer to the location to modify.
     *  @param[in] val        If \a location is less than \a val it is updated.
     */
    template<typename T> static void MaxValue(volatile T *location, T val)
    {
        EXPONENTIAL_BACKOFF<> backoff;

        T oldVal = Load(location);
        while (oldVal < val && !CompareAndDidSwap(location, oldVal, val))
        {
            backoff.Delay();
            oldVal = Load(location);
        }
    }

    /*!
     * Delay the calling thread in a spin loop, using a processor specific
     * "spin loop hint" if available.
     *
     *  @param[in] delay    The number of iterations for the spin loop.
     */
    static void Delay(unsigned delay)
    {
        ATOMIC_SpinDelay(static_cast<FUND::UINT32>(delay));
    }
};

} // namespace
#endif // file guard
