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lammps/lib/kokkos/core/src/impl/Kokkos_Atomic_Compare_Exchange_Strong.hpp
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Kokkos_Atomic_Compare_Exchange_Strong.hpp
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/*
//@HEADER
// ************************************************************************
//
// Kokkos v. 2.0
// Copyright (2014) Sandia Corporation
//
// Under the terms of Contract DE-AC04-94AL85000 with Sandia Corporation,
// the U.S. Government retains certain rights in this software.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// 1. Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
//
// 2. 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.
//
// 3. Neither the name of the Corporation nor the names of the
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY SANDIA CORPORATION "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 SANDIA CORPORATION OR THE
// 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.
//
// Questions? Contact H. Carter Edwards (hcedwar@sandia.gov)
//
// ************************************************************************
//@HEADER
*/
#if defined( KOKKOS_ENABLE_RFO_PREFETCH )
#include <xmmintrin.h>
#endif
#include <Kokkos_Macros.hpp>
#if defined( KOKKOS_ATOMIC_HPP ) && ! defined( KOKKOS_ATOMIC_COMPARE_EXCHANGE_STRONG_HPP )
#define KOKKOS_ATOMIC_COMPARE_EXCHANGE_STRONG_HPP
namespace Kokkos {
//----------------------------------------------------------------------------
// Cuda native CAS supports int, unsigned int, and unsigned long long int (non-standard type).
// Must cast-away 'volatile' for the CAS call.
#if defined( KOKKOS_ENABLE_CUDA )
#if defined(__CUDA_ARCH__) || defined(KOKKOS_IMPL_CUDA_CLANG_WORKAROUND)
__inline__ __device__
int atomic_compare_exchange( volatile int * const dest, const int compare, const int val)
{ return atomicCAS((int*)dest,compare,val); }
__inline__ __device__
unsigned int atomic_compare_exchange( volatile unsigned int * const dest, const unsigned int compare, const unsigned int val)
{ return atomicCAS((unsigned int*)dest,compare,val); }
__inline__ __device__
unsigned long long int atomic_compare_exchange( volatile unsigned long long int * const dest ,
const unsigned long long int compare ,
const unsigned long long int val )
{ return atomicCAS((unsigned long long int*)dest,compare,val); }
template < typename T >
__inline__ __device__
T atomic_compare_exchange( volatile T * const dest , const T & compare ,
typename Kokkos::Impl::enable_if< sizeof(T) == sizeof(int) , const T & >::type val )
{
const int tmp = atomicCAS( (int*) dest , *((int*)&compare) , *((int*)&val) );
return *((T*)&tmp);
}
template < typename T >
__inline__ __device__
T atomic_compare_exchange( volatile T * const dest , const T & compare ,
typename Kokkos::Impl::enable_if< sizeof(T) != sizeof(int) &&
sizeof(T) == sizeof(unsigned long long int) , const T & >::type val )
{
typedef unsigned long long int type ;
const type tmp = atomicCAS( (type*) dest , *((type*)&compare) , *((type*)&val) );
return *((T*)&tmp);
}
template < typename T >
__inline__ __device__
T atomic_compare_exchange( volatile T * const dest , const T & compare ,
typename Kokkos::Impl::enable_if<
( sizeof(T) != 4 )
&& ( sizeof(T) != 8 )
, const T >::type& val )
{
T return_val;
// This is a way to (hopefully) avoid dead lock in a warp
int done = 0;
unsigned int active = __ballot(1);
unsigned int done_active = 0;
while (active!=done_active) {
if(!done) {
if( Impl::lock_address_cuda_space( (void*) dest ) ) {
return_val = *dest;
if( return_val == compare )
*dest = val;
Impl::unlock_address_cuda_space( (void*) dest );
done = 1;
}
}
done_active = __ballot(done);
}
return return_val;
}
#endif
#endif
//----------------------------------------------------------------------------
// GCC native CAS supports int, long, unsigned int, unsigned long.
// Intel native CAS support int and long with the same interface as GCC.
#if !defined(__CUDA_ARCH__) || defined(KOKKOS_IMPL_CUDA_CLANG_WORKAROUND)
#if defined(KOKKOS_ENABLE_GNU_ATOMICS) || defined(KOKKOS_ENABLE_INTEL_ATOMICS)
inline
int atomic_compare_exchange( volatile int * const dest, const int compare, const int val)
{
#if defined( KOKKOS_ENABLE_RFO_PREFETCH )
_mm_prefetch( (const char*) dest, _MM_HINT_ET0 );
#endif
return __sync_val_compare_and_swap(dest,compare,val);
}
inline
long atomic_compare_exchange( volatile long * const dest, const long compare, const long val )
{
#if defined( KOKKOS_ENABLE_RFO_PREFETCH )
_mm_prefetch( (const char*) dest, _MM_HINT_ET0 );
#endif
return __sync_val_compare_and_swap(dest,compare,val);
}
#if defined( KOKKOS_ENABLE_GNU_ATOMICS )
// GCC supports unsigned
inline
unsigned int atomic_compare_exchange( volatile unsigned int * const dest, const unsigned int compare, const unsigned int val )
{ return __sync_val_compare_and_swap(dest,compare,val); }
inline
unsigned long atomic_compare_exchange( volatile unsigned long * const dest ,
const unsigned long compare ,
const unsigned long val )
{ return __sync_val_compare_and_swap(dest,compare,val); }
#endif
template < typename T >
inline
T atomic_compare_exchange( volatile T * const dest, const T & compare,
typename Kokkos::Impl::enable_if< sizeof(T) == sizeof(int) , const T & >::type val )
{
union U {
int i ;
T t ;
KOKKOS_INLINE_FUNCTION U() {};
} tmp ;
#if defined( KOKKOS_ENABLE_RFO_PREFETCH )
_mm_prefetch( (const char*) dest, _MM_HINT_ET0 );
#endif
tmp.i = __sync_val_compare_and_swap( (int*) dest , *((int*)&compare) , *((int*)&val) );
return tmp.t ;
}
template < typename T >
inline
T atomic_compare_exchange( volatile T * const dest, const T & compare,
typename Kokkos::Impl::enable_if< sizeof(T) != sizeof(int) &&
sizeof(T) == sizeof(long) , const T & >::type val )
{
union U {
long i ;
T t ;
KOKKOS_INLINE_FUNCTION U() {};
} tmp ;
#if defined( KOKKOS_ENABLE_RFO_PREFETCH )
_mm_prefetch( (const char*) dest, _MM_HINT_ET0 );
#endif
tmp.i = __sync_val_compare_and_swap( (long*) dest , *((long*)&compare) , *((long*)&val) );
return tmp.t ;
}
#if defined( KOKKOS_ENABLE_ASM) && defined ( KOKKOS_ENABLE_ISA_X86_64 )
template < typename T >
inline
T atomic_compare_exchange( volatile T * const dest, const T & compare,
typename Kokkos::Impl::enable_if< sizeof(T) != sizeof(int) &&
sizeof(T) != sizeof(long) &&
sizeof(T) == sizeof(Impl::cas128_t), const T & >::type val )
{
union U {
Impl::cas128_t i ;
T t ;
KOKKOS_INLINE_FUNCTION U() {};
} tmp ;
#if defined( KOKKOS_ENABLE_RFO_PREFETCH )
_mm_prefetch( (const char*) dest, _MM_HINT_ET0 );
#endif
tmp.i = Impl::cas128( (Impl::cas128_t*) dest , *((Impl::cas128_t*)&compare) , *((Impl::cas128_t*)&val) );
return tmp.t ;
}
#endif
template < typename T >
inline
T atomic_compare_exchange( volatile T * const dest , const T compare ,
typename Kokkos::Impl::enable_if<
( sizeof(T) != 4 )
&& ( sizeof(T) != 8 )
#if defined(KOKKOS_ENABLE_ASM) && defined ( KOKKOS_ENABLE_ISA_X86_64 )
&& ( sizeof(T) != 16 )
#endif
, const T >::type& val )
{
#if defined( KOKKOS_ENABLE_RFO_PREFETCH )
_mm_prefetch( (const char*) dest, _MM_HINT_ET0 );
#endif
while( !Impl::lock_address_host_space( (void*) dest ) );
T return_val = *dest;
if( return_val == compare ) {
// Don't use the following line of code here:
//
//const T tmp = *dest = val;
//
// Instead, put each assignment in its own statement. This is
// because the overload of T::operator= for volatile *this should
// return void, not volatile T&. See Kokkos #177:
//
// https://github.com/kokkos/kokkos/issues/177
*dest = val;
const T tmp = *dest;
#ifndef KOKKOS_COMPILER_CLANG
(void) tmp;
#endif
}
Impl::unlock_address_host_space( (void*) dest );
return return_val;
}
//----------------------------------------------------------------------------
#elif defined( KOKKOS_ENABLE_OPENMP_ATOMICS )
template< typename T >
KOKKOS_INLINE_FUNCTION
T atomic_compare_exchange( volatile T * const dest, const T compare, const T val )
{
T retval;
#pragma omp critical
{
retval = dest[0];
if ( retval == compare )
dest[0] = val;
}
return retval;
}
#endif
#endif
template <typename T>
KOKKOS_INLINE_FUNCTION
bool atomic_compare_exchange_strong(volatile T* const dest, const T compare, const T val)
{
return compare == atomic_compare_exchange(dest, compare, val);
}
//----------------------------------------------------------------------------
} // namespace Kokkos
#endif
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