Path: utzoo!attcan!uunet!husc6!mailrus!ames!oliveb!tymix!antares!jms
From: jms@antares.UUCP (joe smith)
Newsgroups: comp.arch
Subject: Re: ZISC computers
Summary: Weitek is a ZISC
Keywords: ZISC
Message-ID: <278@antares.UUCP>
Date: 23 Nov 88 01:05:49 GMT
References: <22115@sgi.SGI.COM>
Reply-To: jms@antares.UUCP (joe smith)
Organization: Tymnet QSATS, San Jose CA
Lines: 21

In article <22115@sgi.SGI.COM>, karsh@trifolium.SGI.COM (Bruce Karsh) writes:
> Why bother with reduced instruction set computers when a computer
> really doesn't need any instructions per se at all?  At the end of the
> RISC road is the ZISC, Zero Instruction Set Computer.
> 
: I'v never seen a computer architecture such as this (ZISC) proposed
: before.  I'd like to know if anybody else has suggested this idea before.

The March 1988 issue of BYTE magazine has an article on a ZISC that plugs into
the Compaq 386/20 PC and costs $1999.  It's called the Weitek WTL 1167
Math Coprocessor Board.  You store one operand in the chip by writing to a
magic location.  When you write the second operand in another magic location,
poof!  The two floating-point numbers are added and their sum appears at a
third magic location.  The 80386 thinks it's simply doing load/store
operations on memory that happens to have a few wait states.

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