Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!killer!ames!pasteur!ucbvax!decwrl!pyramid!cbmvax!snark!eric
From: eric@snark.UUCP (Eric S. Raymond)
Newsgroups: comp.arch
Subject: Re: Compiler complexity (was: VAX Always Uses Fewer Instructions)
Summary: You forgot the RISC crowd's favorite horror story
Message-ID: 
Date: 23 Jun 88 11:02:36 GMT
References: <6921@cit-vax.caltech.edu> <28200161@urbsdc> <10595@sol.arpa> <20338@beta.lanl.gov> <1117@ima.isc.com> <1127@ima.isc.com>
Organization: Willam Claude Dukenfield Discordian Cabal
Lines: 18

In article <1127@ima.isc.com>, samples@dougfir.Berkeley.EDU (A. Dain Samples) writes:
>A slight correction needs to be made here: there is only one instance
>that I know of where a complex instruction on a CISC architecture turned
>out to run more slowly than the same operation coded with simpler
>instructions ON THE SAME MACHINE. 

And the moderator clarifies:
>[As dmr noted in his recent comp.arch note, it was the 780's calling
>instructions.]

Eh? You both forgot the RISC crowd's favorite horror story -- the VAX POLY
instruction for evaluating a polynomial in x in one swell foop, given
x and the coefficients. Turns out this is always slower than a loop using
simpler instructions.
-- 
      Eric S. Raymond                     (the mad mastermind of TMN-Netnews)
      UUCP: {{uunet,rutgers,ihnp4}!cbmvax,rutgers!vu-vlsi,att}!snark!eric
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