Path: utzoo!utgpu!watserv1!watmath!att!occrsh!uokmax!apple!julius.cs.uiuc.edu!wuarchive!decwrl!sgi!bron@bronze.wpd.sgi.com
From: bron@bronze.wpd.sgi.com (Bron Campbell Nelson)
Newsgroups: comp.sys.sgi
Subject: Re: Benchmarking the SGI: Floating point faster than integer?
Summary: Your right
Keywords: Benchmark floating integer sgi fortran FLOPS
Message-ID: <69040@sgi.sgi.com>
Date: 11 Sep 90 17:56:15 GMT
References: <1464@ruunsa.fys.ruu.nl>
Sender: guest@sgi.sgi.com
Organization: Silicon Graphics, Inc., Mountain View, CA
Lines: 22

In article <1464@ruunsa.fys.ruu.nl>, chooft@ruunsa.fys.ruu.nl (Rob Hooft) writes:
> As I am planning to buy a PC, I am benchmarking all computers available to
> me. On our PI this resulted in a 'pleasant' surprise: Floating point
> multiplications are about twice as fast as integer multiplications. Is there
> anybody that can explain the results of the following session to me?
[session deleted]

The explaination  is simple: on the MIPS R2000 and R3000 cpus, floating
point multiplication *IS* about twice as fast as integer multiplication
(actually, a bit more than twice as fast).  The ratio for division is
even greater.

My understanding is that MIPS decided to throw a lot of silicon at the
floating point problem, while they found that the majority of integer
multiplies in "real" programs involved a constant term, and so could be
done with shifts and adds.  Thus, less silicon was thrown at the integer
multiply problem (and even less at the integer divide).

--
Bron Campbell Nelson
bron@sgi.com  or possibly  ..!ames!sgi!bron
These statements are my own, not those of Silicon Graphics.