Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!wuarchive!usc!apple!altos!altos86!rcollins
From: rcollins@altos86.Altos.COM (Robert Collins)
Newsgroups: comp.sys.ibm.pc.misc
Subject: Re: How do I determine the clock speed?
Keywords: Clock Speed Timer
Message-ID: <4478@altos86.Altos.COM>
Date: 10 Dec 90 16:41:11 GMT
References: <1990Dec3.061630.22992@ux1.cso.uiuc.edu> <1069@idcapd.idca.tds.philips.nl> <1990Dec7.191240.7768@ux1.cso.uiuc.edu>
Reply-To: rcollins@altos86.UUCP (Robert Collins)
Organization: Altos Computer Systems, San Jose, CA
Lines: 26

>robl@idca.tds.PHILIPS.nl (R. Luursema) writes:
>
>> Basically, you can't determine the CPU clockspeed of an arbitrary PC.
>>

Oh really?  It isn't that hard.  I've got a subroutine that is accurate to
1 decimal point (33Mhz = 33Mhz +- .1Mhz).  For the majority of the time, it
is 100% accurate.

I'll give you a hint:
* The timer chip has 838nS resolution
* Execute 838 of the same instructions (with a known CPU_CLOCK count) and
  time them.

I'll leave the rest of this as an excersize to the reader (the programmer),
as I don't feel like reducing my competitive advantage in the job market.

P.S. This algorithm as it stands will be good to about 60Mhz.



-- 
"Worship the Lord your God, and serve him only."  Mat. 4:10
Robert Collins                 UUCP:  ...!sun!altos86!rcollins
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