Path: utzoo!utgpu!news-server.csri.toronto.edu!rutgers!uwm.edu!zaphod.mps.ohio-state.edu!usc!apple!metaphor!dragon!djh
From: djh@dragon.metaphor.com (Dallas J. Hodgson)
Newsgroups: comp.sys.amiga.tech
Subject: Re: MC68881/2 Support (hello, Dave Haynie)
Message-ID: <1190@metaphor.Metaphor.COM>
Date: 5 Jun 90 21:29:44 GMT
References: <1181@metaphor.Metaphor.COM> <11996@cbmvax.commodore.com> <1183@metaphor.Metaphor.COM> <10341@batcomputer.tn.cornell.edu> <1430@marlin.NOSC.MIL>
Sender: news@metaphor.Metaphor.COM
Reply-To: djh@dragon.metaphor.com (Dallas J. Hodgson)
Distribution: comp.sys.amiga.tech
Organization: Metaphor Computer Systems, Mountain View, CA
Lines: 24


I should mention something I found recently on a late-model Fish disk; it's
called "mathtrans", and was written by a German programmer as a 68881
replacement for MathTrans.library. Let it be known that even tho' his
library has to translate between IEEE and FFP for Every Call, it STILL
performs 2-7x faster on 68881/2 equipped machines. So much for the "overhead
is too high for this sort of thing to be done" myth. On my A3000, the
averaged improvement was about 3.4%. Your mileage may vary.

Benchmark People note : Dhrystone 1.1 runs 5150 on a 25MHz A-3000 using 32-bit
ints, registers enabled, caches (but not bursts) on. 5500 dhrystones using
16-bit ints. These numbers courtesy of Aztec C 5.0.

Now: Run NoFastMem and try again. 5500 dhrystones -> 1200 dhrystones. No
DMA contention going on other than an interlaced 2bitplane WB screen and the
Intuition sprite.
+----------------------------------------------------------------------------+
| Dallas J. Hodgson               |     "This here's the wattle,             |
| Metaphor Computer Systems       |      It's the emblem of our land.        |
| Mountain View, Ca.              |      You can put it in a bottle,         |
| USENET : djh@metaphor.com       |      You can hold it in your hand."      |
+============================================================================+
| "The views I express are my own, and not necessarily those of my employer" |
+----------------------------------------------------------------------------+