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From: ucbesvax.turner@ucbcad.UUCP
Newsgroups: net.arch
Subject: uP architecture - (nf)
Message-ID: <189@ucbcad.UUCP>
Date: Thu, 30-Jun-83 12:24:47 EDT
Article-I.D.: ucbcad.189
Posted: Thu Jun 30 12:24:47 1983
Date-Received: Fri, 1-Jul-83 22:24:42 EDT
Sender: notes@ucbcad.UUCP
Organization: UC Berkeley, CAD Group
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#N:ucbesvax:12800003:000:1097
ucbesvax!turner    Jun 30 01:18:00 1983

	Can anyone venture a theory as to why many microprocessor
architectures are so terrible?  I am referring here to 8080 and its
derivatives.  It's hard for me to believe that there just weren't
good architects around at the time, or that the medium was the main
constraint.

	I am told that Datapoint machines are TTL implementations of
a slight variant of 8080.  And that the 8080 was originally a design
commissioned by the Japanese phone company, who later rejected it as
too slow for their purposes.  These stories could be apocryphal.

	Why wasn't the first uP a Nova?  Or perhaps a PDP-11 subset?
Or at least something *good*?  The 6800 was a reasonably intelligent
design, since it as much as said: "forget speed, use stacks", and
provide (voila!) a stack-oriented architecture.  The much-later 6809
is, to my mind, the first really good 8-bit machine to appear, and
seems to take a position midway between the 6800 and the 68000.

	Finally, has anyone heard of the 1802, which I have been told
is a very slow but architecturally elegant CMOS uP?

		Michael Turner
		ucbvax!ucbesvax.turner