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From: mir@chorus.fr (Adam Mirowski)
Newsgroups: comp.sys.ibm.pc.misc
Subject: Re: finding out MHz rate of processor (like norton 5.0 )
Keywords: MHz speed processors norton
Message-ID: <7850@chorus.fr>
Date: 12 Feb 91 19:08:44 GMT
References: <4833@ruuinf.cs.ruu.nl>
Reply-To: mir@opera.chorus.fr (Adam Mirowski)
Organization: Chorus systemes, Saint Quentin en Yvelines, France
Lines: 17

In article <4833@ruuinf.cs.ruu.nl>, ajbanck@cs.ruu.nl (Arent Banck) writes:
%% Looking at the norton utilities 5.0, I saw that it checked the 
%% freq. at wich the processor runs.
%% Does anybody know if there is an easy way of finding this freq.
%% And where I can find this. Also, does anybody know how nu is checking
%% this frequency?

You have to know how many clock ticks a given instruction takes,
then repeat it many times, for example in a loop. There is a 838
nanoseconds-resolution timer in the PC which can be used to measure
the spent time with precision. Then you divide the total number of
clocks by the time spent and you get the frequency.
In order to implement this efficiently, you also have to figure out
how to minimize memory access during the loop.
-- 
Adam Mirowski,  mir@chorus.fr (FRANCE),  tel. +33 (1) 30-64-82-00 or 74
Chorus systemes, 6, av.Gustave Eiffel, 78182 Saint-Quentin-en-Yvelines CEDEX