如何在Visual C ++中检测rdtscp支持? [英] How to detect rdtscp support in Visual C++?

问题描述

我在MSVC 2012上运行了一段代码:

I have a piece of code running on MSVC 2012:

#include <windows.h>
#include <intrin.h> 

UINT64 gettime() {
 try {
     unsigned int ui;
     return __rdtscp(&ui);
 }
 catch (...) {
     return __rdtsc();
 }
}

我试图使用__rdtscp()获取时间戳；但是，在不支持__rdtscp()的平台上，我想改用__rdtsc().

I was trying to use __rdtscp() to get the timestamp; however, on the platform where the __rdtscp() is not supported, I want to switch to __rdtsc() instead.

上面的代码不起作用；如果不支持__rdtscp()，则该程序仅会崩溃(在某些VM上).那么，有什么方法可以检测到是否支持__rdtscp()，但又不会使程序崩溃?

The above code doesn't work; the program simply crashed if the __rdtscp() is not supported (on certain VMs). So is there any way I can detect if the __rdtscp() is supported, but without crashing the program?

推荐答案

从MSDN for rdtscp:

From MSDN for rdtscp:

要确定对此指令的硬件支持，请调用InfoType = 0x80000001的__cpuid内在函数，并检查CPUInfo [3](EDX)的位27.如果支持该指令，则该位为1，否则为0.

To determine hardware support for this instruction, call the __cpuid intrinsic with InfoType=0x80000001 and check bit 27 of CPUInfo[3] (EDX). This bit is 1 if the instruction is supported, and 0 otherwise.

这篇关于如何在Visual C ++中检测rdtscp支持?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！