Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!usc!cs.utexas.edu!rutgers!cbmvax!daveh
From: daveh@cbmvax.commodore.com (Dave Haynie)
Newsgroups: comp.sys.amiga.advocacy
Subject: Re: '040 and '882
Message-ID: <20377@cbmvax.commodore.com>
Date: 4 Apr 91 21:54:28 GMT
References: <2577@ria.ccs.uwo.ca> <2602@ria.ccs.uwo. <12391@pasteur.Berkeley.EDU> <1991Apr3.225839.11602@motaus.sps.mot.com>
Reply-To: daveh@cbmvax.commodore.com (Dave Haynie)
Organization: Commodore, West Chester, PA
Lines: 31

In article <1991Apr3.225839.11602@motaus.sps.mot.com> skipper@motaus.sps.mot.com (Skipper Smith) writes:

>If you really feel the need for heavy duty FP, you shouldn't be using the 
>68040 or an '882, anyway.  The '882 at 25 MHz is only about .5-.6 MFLOPS and
>the '040 (on hardware-only instructions) is about 3.2-3.5 MHz.  

Which also points out that, even given what looks to me like some real 
speedups in instruction emulation on the '040 vs. the '030, especially for
floating point, if your compiler has an '040 switch for floating point math,
you may get better results than running plain '882 code.  Lots of things can
be in-lined more efficiently than trapped, at a slight code size increase.

>Somebody should be designing a 96002 board for the Amiga- it cooks along at 
>60 MFLOPS@40 MHz (and 40 MFLOPS @ 25 MHz)- and updating software to use it.

Dedicated renders and other real heavyweight floating point programs would 
find such a board a _real_ nice home.  However, what the Amiga really needs
is a high level math server, which lots of relatively complex floating point
functions supported.  The idea here is that the cost of a server dispatch is
minor when compared to the function's execution time on the floating point
board.  And because of the intelligent server, you could dispatch any given
function to any free FPU board that can perform the function, even if they're
different animals -- even a mix of 96002s and i860s could work (wouldn't that
make the SPARCs fly....).

>Skipper Smith                             | skipper@motaus.sps.mot.com

-- 
Dave Haynie Commodore-Amiga (Amiga 3000) "The Crew That Never Rests"
   {uunet|pyramid|rutgers}!cbmvax!daveh      PLINK: hazy     BIX: hazy
      "That's me in the corner, that's me in the spotlight" -R.E.M.