Xref: utzoo comp.misc:2410 comp.arch:4857
Path: utzoo!attcan!uunet!husc6!mailrus!bcm!uhnix2!uhnix1!sugar!karl
From: karl@sugar.UUCP (Karl Lehenbauer)
Newsgroups: comp.misc,comp.arch
Subject: Japanese 32-bit micro can be a 68020 or 80386
Message-ID: <2006@sugar.UUCP>
Date: 17 May 88 00:53:41 GMT
Organization: Sugar Land UNIX - Houston, TX
Lines: 40

There is an article in this week's "PC Week" magazine about a 32-bit micro
developed in Japan by a joint venture of a couple of major players there
(sorry, I don't have the article at hand) that has a writable control store 
and thus can have different microprograms loaded into it to emulate the 80386,
68020 and others, apparently as a means of getting around microcode copyright 
issues that have prevented Japanese manafacturers from cloning those processors.
It's called VM, for Virtual Microprocessor.

Even the immediate implications are stunning, I think.  One thing is that 
those of us who have always wanted to diddle microcode may soon be able to, 
tho' there won't be much software or software compatibility for those who
do (the Microprogramming Construction Set?).  It would be a boon to
researchers and others trying to implement oddball language architectures
and get them to execute efficiently on a CISC-type machine (Smalltalk, LISP, 
etc.)

Another thing is that it could be more desirable to have a microprogrammable
machine than not, for the wider compatibility it could offer (a lot of work
required to implement that range of compatibility, though.)  

Imagine a version of the microprogrammable chip in which the operating system 
could context switch among trusted sets of microprograms.  Weird.

Imagine a virtual personal computer which, on exactly the same hardware, 
could be a DOS-compatible 80386 workstation or a 68020 workstation, with 
microcode and software being the only differences.  How about a
Forth machine?  A Vax?

If tangible benefits beyond end-running microcode copyright issues are
provided, reasonably soon, American uP manafacturers will need to develop 
their own microprogrammable machines, unless they're certain of their RISC 
architectures, because people will buy them.  If the processor is only
used as a means of getting around the copyright problem, it's no big deal 
to us as microprocessor consumers which we would use other than price,
performance and reliability, although I imagine it is regarded as a 
very big deal by Motorola and Intel and any other manafacturers selling
processors that this processor can emulate.
-- 
"Now here's something you're really going to like!" -- Rocket J. Squirrel
..!{bellcore!tness1,uunet!nuchat}!sugar!karl, Unix BBS (713) 438-5018