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Name: unknown
Date: September 30, 2003 at 15:51:36
Subject: Re: Question about RDTSC programming
In Reply To: Question about RDTSC programming by
Jag on September 30, 2003 at 15:08:16
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.
optional link: ftp://download.intel.com/design/Xeon/applnots/24161823.pdf


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