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Name: unknown
Date: September 30, 2003 at 16:15:05
Subject: Re: Question about RDTSC programming
In Reply To: Re: Question about RDTSC programming by
unknown on September 30, 2003 at 15:51:36
Text: | To calculate the CPU speed you need to use the 8254 timer (ports 40h-43h)
| It has a resolution of 838ns and is the same on all PCs and has been so
| since the original IBM PC. Depending on what you're doing you might want
| to just use the 8254 timer in your game engine.
|
| The link points to Intel's CPUID document which includes code to calculate
| the CPU speed. Getting the bus speed and multiplier involves reading MSRs
| and is different between processor families. You shouldn't really need that
| info anyway in a game engine.
|

Hey thanks for getting back to me, I will look into that doc. Ya I shouldnt need to access the MSR but i thought I could get the speed by Bus x multiplier but if this way works thats great. How accurate is it? Thanks


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