From:	<telford AT xenon DOT triode DOT net DOT au>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: how to find out what processor is being used??
Date:	15 Mar 1998 13:34:22 GMT
Organization:	Triode Internet
Lines:	26
Message-ID:	<6eglcu$ad6$3@hyperion.triode.net.au>
References:	<199803150138 DOT RAA29692 AT adit DOT ap DOT net>
NNTP-Posting-Host:	xenon.triode.net.au
Mime-Version:	1.0
To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp

In comp.os.msdos.djgpp Nate Eldredge <eldredge AT ap DOT net> wrote:
> At 12:42  3/13/1998 GMT, Perry DOT Fecteau AT Republican DOT COM wrote:
> >i'm guessing it's a bios call.  or is there an address i can find this
> >information in?

> Nothing so simple. It depends on just what you want to know.

The Linux kernel code snoops out the model, some brand details (not much),
whether there is an FPU bug, and takes a rough speed measurement
called BogoMIPS. Well all of the routines to do this are in publicly
readable source code form but understanding exactly how they work is
a bit tricky.

The basic rule for timing critical situations is to use the hardware
timer interrupt 0. The Linux people found out that there are situations
where very brief time intervals must be generated and this is what the
BogoMIPS are used for. The old standby for graphics programs is to base
everything off the video refresh (a programmable interrupt on most
VGA cards) this keeps flicker off the screen and gives a known time-frame
for actions to take place within. Again, it's not much use for very
brief time intervals.

	- Tel

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