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From: wmb@sun.uucp (Mitch Bradley)
Newsgroups: net.arch
Subject: Re: looking for stack machines
Message-ID: <553@sun.uucp>
Date: Tue, 6-Mar-84 22:27:29 EST
Article-I.D.: sun.553
Posted: Tue Mar  6 22:27:29 1984
Date-Received: Thu, 8-Mar-84 07:41:11 EST
References: <3523@tekecs.UUCP> <27900008@ucbesvax.UUCP>
Organization: Sun Microsystems, Inc.
Lines: 25

Charles Moore, the inventor of FORTH, is building a FORTH machine.
He described it a the FORTH Modification Laboratory conference at
Asilomar last November.  Unfortunately, his presentation was verbal,
and there was not a written version in the conference proceedings.
Basically his is an ECL processor with 2 hardware stacks, one for
passing arguments and the other for holding return addresses for
subroutines (FORTH programmers will recognize this architecture as
closely resembling the FORTH virtual machine).  Both the top-of-stack
and the second-on-stack are instantly accessible (i.e. in one
microcycle) for both stacks.  The machine is microcoded in such a way
that FORTH code may be easily compiled into a near-optimal set of
microinstructions.  The mapping is interesting.  In one particular
case, a sequence of 5 FORTH operations compiles into a single
microinstruction.

In November, he showed the film for his PC board, which he had just
gotten back from the photo house.  He expects the first rev of the
computer to run with a 16 nsec. microcycle time.

He did all of the design work on a home-brew CAD system (written in
FORTH of course) which was pretty impressive, but not general purpose.
It runs on an 11/23, and does layout, simulation, timing analysis, etc.

				Mitch Bradley
				Sun Microsystems, Inc.