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++ // Copyright 2009-2021 Intel Corporation
++ // SPDX-License-Identifier: Apache-2.0
++
++ #pragma once
++
++ #include <atomic>
++ #include "intrinsics.h"
++
++ namespace embree
++ {
++ /* compiler memory barriers */
++ #if defined(__INTEL_COMPILER)
++ //#define __memory_barrier() __memory_barrier()
++ #elif defined(__GNUC__) || defined(__clang__)
++ # define __memory_barrier() asm volatile("" ::: "memory")
++ #elif defined(_MSC_VER)
++ # define __memory_barrier() _ReadWriteBarrier()
++ #endif
++
++ template <typename T>
++ struct atomic : public std::atomic<T>
++ {
++ atomic () {}
++
++ atomic (const T& a)
++ : std::atomic<T>(a) {}
++
++ atomic (const atomic<T>& a) {
++ this->store(a.load());
++ }
++
++ atomic& operator=(const atomic<T>& other) {
++ this->store(other.load());
++ return *this;
++ }
++ };
++
++ template<typename T>
++ __forceinline void atomic_min(std::atomic<T>& aref, const T& bref)
++ {
++ const T b = bref.load();
++ while (true) {
++ T a = aref.load();
++ if (a <= b) break;
++ if (aref.compare_exchange_strong(a,b)) break;
++ }
++ }
++
++ template<typename T>
++ __forceinline void atomic_max(std::atomic<T>& aref, const T& bref)
++ {
++ const T b = bref.load();
++ while (true) {
++ T a = aref.load();
++ if (a >= b) break;
++ if (aref.compare_exchange_strong(a,b)) break;
++ }
++ }
++ }