Path: utzoo!attcan!uunet!samsung!zaphod.mps.ohio-state.edu!wuarchive!psuvax1!rutgers!att!tsdiag!pedsga!petsd!tinton!dan
From: dan@tinton.UUCP
Newsgroups: comp.sys.ibm.pc
Subject: Re: Why The Move To RISC Architectures?  ('386 vs. RISC)
Message-ID: <1990Mar27.214211.22328@tinton>
Date: 27 Mar 90 21:42:11 GMT
References: <28011@cup.portal.com> <26083220.22927@maccs.dcss.mcmaster.ca> <10453@portia.Stanford.EDU> <8564@pt.cs.cmu.edu>
Reply-To: dan@tinton.UUCP (Daniel Masi <masid>)
Organization: Concurrent Computer Corp., Tinton Falls, N.J.
Lines: 24

In article <8564@pt.cs.cmu.edu> ralf@b.gp.cs.cmu.edu.UUCP writes:
>In article <10453@portia.Stanford.EDU> dhinds@portia.Stanford.EDU (David Hinds) writes:
>}some RISC features.  Why?  Because it is fast?  It seems to me that the
>}80486 is instead the antithesis - and nemesis - of RISC technology.  If
>}we now have the ability to design a CISC processor so efficiently that
>}most of its instructions take only a cycle or two, why move to a less
>}complex architecture?  The 80486 had sufficient circuit space left over
>}for a respectable amount of support stuff, as well.  You could say, well,
>
>Yeah, but how many RISC CPUs have 1.2 million transistors?  That's something
>like EIGHT to TEN times as many gates as the typical RISC CPU....

Nope.  The 'typical' RISC CPU will have as many transistors as the 
typical CISC CPU.  The commercial RISC CPU I am currently designing with 
has 1.0 million.  They are just USED DIFFERENTLY (put to better use,
IMHO).  In a typical RISC part, you need less transistors for the CPU 
portion, thus you can include more support-type functionality (cache 
control, cache RAM, floating point, etc) on-chip.

----------------------------------------------------------------
Dan Masi             (dan@tinton.tinton.ccur.com)  201-758-7699
Concurrent Computer Corp.
106 Apple Street
Tinton Falls, NJ  07724