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From: braner@batcomputer.UUCP
Newsgroups: comp.sys.atari.st
Subject: Re: Floating Point Benchmarks
Message-ID: <580@batcomputer.tn.cornell.edu>
Date: Tue, 31-Mar-87 20:02:16 EST
Article-I.D.: batcompu.580
Posted: Tue Mar 31 20:02:16 1987
Date-Received: Sat, 4-Apr-87 04:04:23 EST
References: <470@batcomputer.tn.cornell.edu> <817@bobkat.UUCP>
Reply-To: braner@batcomputer.UUCP (braner)
Distribution: world
Organization: Theory Center, Cornell University, Ithaca NY
Lines: 21
Summary: Yes, a 68881 would be nice.  Megamax: give us a new FP lib.

[]

I do agree that a 68881 would be wonderful to have, even on a 68000
machine.  But don't let that benchmark trick you into thinking that
the penalty for running the 68881 as a peripheral is less than 2:1.
The Savage benchmark tests _only_ transcendental functions, where the
calculation time (inside the 68881) dominates.  In most real-life programs
there will be lots of lowly add/sub/mul/div FP ops, where the overhead
of communicating with the FP chip is very important (especially when
you don't have an optimizing compiler that would keep everything inside
the 68881 registers as far as possible).

I am happy to hear that Megamax is finally about to upgrade its FP
package (or what passed for one).  If the complaints on the net
and the comparative benchmarks gave the necessary push, then it proves
the net's value...  (As things currently are, Megamax's FP lib is an order
of magnitude slower _and_ buggier than _either_ MWC or Alcyon!)
I hope that upgrade is really coming, and that Megamax C owners will be
notified and given upgrades.

- Moshe Braner