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From:	CBFalconer <cbfalconer AT yahoo DOT com>
Organization:	Ched Research
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Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: RDTSC ?
References:	<Pine DOT A41 DOT 4 DOT 05 DOT 10112030837410 DOT 57664-100000 AT ieva06>
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Date:	Mon, 03 Dec 2001 14:32:53 GMT
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Andris Pavenis wrote:
> 
> On Sun, 2 Dec 2001, Damien Knight wrote:
> 
> > As I've been told, RDTSC is a feature of pentium (and up) processers that
> > tracks the number of processer cycles completed since the system last
> > powered up, making it useful for calculating system uptime - but more
> > importantly, it can be used to test code optimization and so on.
> >
> > My question : How do I get this value and use in in a DJGPP program?  If
> > anyone has a function already written, that'd be great.
> 
> inline long long rdtsc (void)
> {
>         long long result;
>         asm volatile ("rdtsc" : "=A"(result));
>         return result;
> }

And if you call this function on a 486 you get a crash.  So guard
it by checking the actual CPU first.

-- 
Chuck F (cbfalconer AT yahoo DOT com) (cbfalconer AT XXXXworldnet DOT att DOT net)
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