The Code Project - Whats my CPU Speed?

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Whats my CPU Speed?
By Colin Davies

Some simple functions for system stats

	VC6, Win95, Win98, NT4, MFC
	Posted 29 Jun 2000
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Download demo project - 34 Kb

Sample Image - SysInfox.jpg
As you can see I should upgrade my PC :-)

CPU Speed and other stuff

Recently I had a small games developer ask me to develop some functions for determining some windows platform statistics of the Users. So really this project was going to be modified to being a DLL, but it never got to that stage. And thus was never used and I'm posting it here instead :-)

CPU Speed

I discovered this to be a fascinating topic being a non HardWare guy, And learn't a lot of irrelevant stuff in the process

Intel supplies a cpuinf32.dll to recover the CPU speed from a time stamp, (However this fails on overclocked PC's and illegal cloned CPU's)
There are a host of methods for calculating the CPU speed.
CPU speeds vary greatly with temperature and voltage differences.

However the method I finally used to get the CPU speed was quite simplistic,

inline unsigned __int64 theCycleCount(void)
{  
    _asm    _emit 0x0F
    _asm    _emit 0x31
    
	/// this causes a compiler warning as there is no return statement
	/// however the "_emits" return a __int64 value
}

class CTimer
{
    unsigned __int64  m_start;

public:

    unsigned __int64  m_overhead;

    CTimer(void)
    {
        m_overhead = 0;
        Start();              /// we get the start cycle
        m_overhead = Stop();  // then we get the stop cycle catching the overhead time
    }
    
    void Start(void)
    {
        m_start = theCycleCount();
    }

    unsigned __int64 Stop(void)
    {
	/// with the stop cycle we remove the overhead's time
        return theCycleCount()-m_start-m_overhead;
    }
};

and

void CSysInfoDlg::OnButtonRawclockfrequency() 
{
	CString strRawClockFrequency;
	CTimer timer;

	long tickslong;
	long tickslongextra;
	timer.Start(); Sleep(1000); 
	unsigned cpuspeed100 = (unsigned)(timer.Stop()/10000);
	tickslong = cpuspeed100/100;
	tickslongextra = cpuspeed100-(tickslong*100);
	strRawClockFrequency.Format("%d.%d   MHZ   estimate ",
	tickslong,tickslongextra  );
	m_RawClockFrequencyControl.SetWindowText(strRawClockFrequency);
}

The other stuff?

The other stuff is for getting the window size settings and the amount of RAM available, I'm unsure if the RAM functions are indeed acurate, But hey they return a value, :-)

Anyhow...

Good luck to anyone who finds a use for this code.

About Colin Davies

NZ based independant developer

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