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Mail Archives: djgpp-workers/1999/08/06/08:26:33

Date: Thu, 5 Aug 1999 19:34:03 +0200 (METDST)
Message-Id: <199908051734.TAA19839@tyr.diku.dk>
From: Morten Welinder <terra AT diku DOT dk>
To: djgpp-workers AT delorie DOT com
Subject: Re: CPU ID program, second version
Reply-To: djgpp-workers AT delorie DOT com

> And software environment cannot do anything about CPU's inability to
> change the state of flag.

Sure it can, and some do it.  Unless you are in real mode or ring 0,
the "popf" instruction will do what the operating environment wants
it to do.  It will not just move flags from the stack to the flags
register.

I have seen cases where the AC flag could not be turned on at all,
even on a 486+.  Your code would say "386" for any CPU under such
environments.

Regarding the switch and default: you should be prepared for someone
to go out and buy a new machine in two years.  A spiffy i786 perhaps,
who knows?

Morten

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