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From: stevenso@hplabsb.UUCP (David Stevenson)
Newsgroups: comp.misc,comp.arch
Subject: Re: Japanese 32-bit micro can be a 68020 or 80386
Summary: Shima's previous chip designs
Message-ID: <4714@hplabsb.UUCP>
Date: 19 May 88 23:19:25 GMT
References: <2006@sugar.UUCP> <53780@sun.uucp>
Organization: Hewlett-Packard Laboratories
Lines: 15

In article <53780@sun.uucp>, david@sun.uucp (David DiGiacomo) writes:
>                 As far as I can tell, Shima is designing a 386 clone which
> uses PLAs for instruction decoding and sequencing. 

When I worked at Zilog, I had the opportunity to study the implementation
and documentation of Shima's last USA-based microprocessor (the Z8000 for
those of you with long memories).  The documentation flowcharts looked very
much like microcode (which registers, buses, etc were enabled during each
state transition), but the chip's logic layout was very PLA-ish (in order
to conserve silicon area, not for copyright purposes).  If you want to
see what that chip looked like, see David Patterson's article in the
Scientific American on (gasp!) "Microcode." [Those were the pre-RISC days.]

David Stevenson
HP Labs
hplabs.hp.com