65 lines
1.7 KiB
C
65 lines
1.7 KiB
C
|
/*
|
||
|
|
* Copyright 2016-present Facebook, Inc.
|
||
|
|
*
|
||
|
|
* Licensed under the Apache License, Version 2.0 (the "License");
|
||
|
|
* you may not use this file except in compliance with the License.
|
||
|
|
* You may obtain a copy of the License at
|
||
|
|
*
|
||
|
|
* http://www.apache.org/licenses/LICENSE-2.0
|
||
|
|
*
|
||
|
|
* Unless required by applicable law or agreed to in writing, software
|
||
|
|
* distributed under the License is distributed on an "AS IS" BASIS,
|
||
|
|
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
||
|
|
* See the License for the specific language governing permissions and
|
||
|
|
* limitations under the License.
|
||
|
|
*/
|
||
|
|
|
||
|
|
#pragma once
|
||
|
|
|
||
|
|
#include <folly/Portability.h>
|
||
|
|
|
||
|
|
#include <chrono>
|
||
|
|
#include <cstdint>
|
||
|
|
|
||
|
|
#ifdef _MSC_VER
|
||
|
|
#include <intrin.h>
|
||
|
|
#endif
|
||
|
|
|
||
|
|
namespace folly {
|
||
|
|
inline void asm_volatile_memory() {
|
||
|
|
#if defined(__clang__) || defined(__GNUC__)
|
||
|
|
asm volatile("" : : : "memory");
|
||
|
|
#elif defined(_MSC_VER)
|
||
|
|
::_ReadWriteBarrier();
|
||
|
|
#endif
|
||
|
|
}
|
||
|
|
|
||
|
|
inline void asm_volatile_pause() {
|
||
|
|
#if defined(_MSC_VER) && (defined(_M_IX86) || defined(_M_X64))
|
||
|
|
::_mm_pause();
|
||
|
|
#elif defined(__i386__) || FOLLY_X64
|
||
|
|
asm volatile("pause");
|
||
|
|
#elif FOLLY_AARCH64 || defined(__arm__)
|
||
|
|
asm volatile("yield");
|
||
|
|
#elif FOLLY_PPC64
|
||
|
|
asm volatile("or 27,27,27");
|
||
|
|
#endif
|
||
|
|
}
|
||
|
|
|
||
|
|
inline std::uint64_t asm_rdtsc() {
|
||
|
|
#if _MSC_VER
|
||
|
|
return (uint64_t)__rdtsc();
|
||
|
|
#elif defined(__i386__) || FOLLY_X64
|
||
|
|
// read the timestamp counter on x86
|
||
|
|
auto hi = std::uint32_t{};
|
||
|
|
auto lo = std::uint32_t{};
|
||
|
|
asm volatile("rdtsc" : "=a"(lo), "=d"(hi));
|
||
|
|
return (((std::uint64_t)lo) + (((std::uint64_t)hi) << 32));
|
||
|
|
#else
|
||
|
|
// use steady_clock::now() as an approximation for the timestamp counter on
|
||
|
|
// non-x86 systems
|
||
|
|
return std::chrono::steady_clock::now().time_since_epoch().count();
|
||
|
|
#endif
|
||
|
|
}
|
||
|
|
} // namespace folly
|