🚀 go-pugleaf

In article <JT.92Oct7214603@fizyk1.fuw.edu.pl> (Jerzy Tarasiuk) writes:
>>>>>> On Wed, 30 Sep 1992 13:42:48 GMT, (menglund) said:
>m> I am wanting to know how to determine a machines clock frequency dynamically
>m> within a program. (eg: 8MHz, 16MHz ect).
>
>I don't see necessity to determine machine clock frequency. You can
>compare periods on the ADC board timer chip and main board timer chip
>(which has always same frequency on its input). Just the 8253 on the
  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>ADC card makes the simplest way to determine the clock frequency!

Unfortuneatly, this is not true.  The higher quality clones will have
the correct clock frequency going to the timer, but there are some
clones that use a cheaper crystal which is off the standard frequency
for the PC clones.

Because of variations in board design, caching, memory archecture,
non-Intel chip vendors and other things it is not possible to determine
the CPU clock frequency via instruction timming with any degree of
accuracy.  The only alternative is to put a timer in of your own
specification.
-- 

rap.

-----------------------------------------------------------------------
Robert A. Pease, Novell Inc.
Internet: rap@novell.COM