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From: apratt@atari.UUCP (Allan Pratt)
Newsgroups: comp.sys.atari.st
Subject: Re: adding a 68881
Message-ID: <1697@atari.UUCP>
Date: 15 Sep 89 21:39:31 GMT
References: <8909131852.a027631@nabla.electrical-engineering.umist.ac.uk> <1989Sep14.084139.17332@newcastle.ac.uk>
Organization: Atari Corp., Sunnyvale CA
Lines: 22

The product you want is the Atari SFP004 Floating-Point Math Peripheral
or some such name.  SFP004 should be sufficient for your dealer to
order one if he doesn't already have one.  It only goes into Megas; it
fits on the internal expansion bus.

Of course, on a 68000 you can't talk to it as well as a 68020 can;
you have to use it in "peripheral mode" where the handshaking protocol
is handled in software, not directly by the CPU.  Only programs compiled
specifically with the SFP004 in mind will run faster; others won't notice it.
(In that respect it is unlike the Blitter.)

The SFP004 comes with a disk, I think, containing the guts of a library
you can merge with Alcyon's libm to make lib81; link your Alcyon C
programs with that library and they will use the SFP004 if it's
installed, and Alcyon's software routins if it's not.  There is also
source for those routines, as examples you can use in assembly language
or for other compilers.  I *think* that disk is part of the SFP004
package; if it's not, it should be available from Atari.

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Opinions expressed above do not necessarily	-- Allan Pratt, Atari Corp.
reflect those of Atari Corp. or anyone else.	  ...ames!atari!apratt