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//===-- Atomic.cpp - Atomic Operations --------------------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This header file implements atomic operations.
//
//===----------------------------------------------------------------------===//
#include "llvm/Support/Atomic.h"
#include "llvm/Config/llvm-config.h"
using namespace llvm;
#if defined(_MSC_VER)
#include <windows.h>
#undef MemoryFence
#endif
#if defined(__GNUC__) || (defined(__IBMCPP__) && __IBMCPP__ >= 1210)
#define GNU_ATOMICS
#endif
void sys::MemoryFence() {
#if LLVM_HAS_ATOMICS == 0
return;
#else
# if defined(GNU_ATOMICS)
__sync_synchronize();
# elif defined(_MSC_VER)
MemoryBarrier();
# else
# error No memory fence implementation for your platform!
# endif
#endif
}
sys::cas_flag sys::CompareAndSwap(volatile sys::cas_flag* ptr,
sys::cas_flag new_value,
sys::cas_flag old_value) {
#if LLVM_HAS_ATOMICS == 0
sys::cas_flag result = *ptr;
if (result == old_value)
*ptr = new_value;
return result;
#elif defined(GNU_ATOMICS)
return __sync_val_compare_and_swap(ptr, old_value, new_value);
#elif defined(_MSC_VER)
return InterlockedCompareExchange(ptr, new_value, old_value);
#else
# error No compare-and-swap implementation for your platform!
#endif
}
sys::cas_flag sys::AtomicIncrement(volatile sys::cas_flag* ptr) {
#if LLVM_HAS_ATOMICS == 0
++(*ptr);
return *ptr;
#elif defined(GNU_ATOMICS)
return __sync_add_and_fetch(ptr, 1);
#elif defined(_MSC_VER)
return InterlockedIncrement(ptr);
#else
# error No atomic increment implementation for your platform!
#endif
}
sys::cas_flag sys::AtomicDecrement(volatile sys::cas_flag* ptr) {
#if LLVM_HAS_ATOMICS == 0
--(*ptr);
return *ptr;
#elif defined(GNU_ATOMICS)
return __sync_sub_and_fetch(ptr, 1);
#elif defined(_MSC_VER)
return InterlockedDecrement(ptr);
#else
# error No atomic decrement implementation for your platform!
#endif
}
sys::cas_flag sys::AtomicAdd(volatile sys::cas_flag* ptr, sys::cas_flag val) {
#if LLVM_HAS_ATOMICS == 0
*ptr += val;
return *ptr;
#elif defined(GNU_ATOMICS)
return __sync_add_and_fetch(ptr, val);
#elif defined(_MSC_VER)
return InterlockedExchangeAdd(ptr, val) + val;
#else
# error No atomic add implementation for your platform!
#endif
}
sys::cas_flag sys::AtomicMul(volatile sys::cas_flag* ptr, sys::cas_flag val) {
sys::cas_flag original, result;
do {
original = *ptr;
result = original * val;
} while (sys::CompareAndSwap(ptr, result, original) != original);
return result;
}
sys::cas_flag sys::AtomicDiv(volatile sys::cas_flag* ptr, sys::cas_flag val) {
sys::cas_flag original, result;
do {
original = *ptr;
result = original / val;
} while (sys::CompareAndSwap(ptr, result, original) != original);
return result;
}
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