FPU on the UNIX pc (was Re: All right! and 1.2M floppies; HwNote05)

[Lenny Tropiano]

In article <3462 at rphroy.UUCP> tkacik at rphroy.UUCP (Tom Tkacik) writes:
|>In article <368 at uncle.UUCP> jbm at uncle.UUCP (John B. Milton) writes:
|>>First thing's first. If you have ANY ideas for hardware enhancements, e-mail
|>>them off to me. Let me know about any special deals for hardware that give 
|>>you the idea and all possible uses you can think of. You will get credit 
|>>for your idea in the form of recognition, but that's all!
|>
|>Fair enough.   I would like to put a floating point chip in my machine.  It is
|>just too slow without it.  It's embarassing to get beaten by XT's and
|>turbo-amigas, etc.
|>
|>I think the hardware should be fairly easy.  Either an internal daughter board
|>or an expansion board,  along with all of the disk drive circuits.
|>The software will be the tricky part.  First the math libraries will need to
|>be re-written, and made compatible with the existing ones.  

I'm not to sure about this, but reading the UNIX System V User's Manual
(vol. II) on cc(1), I saw this:

	"The C compiler uses one of three code generators for the

		CPU=xxxxx,FPU=yyyyy

	where CPU indicates the central processor to generate for and
	FPU indicates the style of floating-point math to use. xxxxx must
	currently be 68010, and yyyyy may be 68881 or SOFTWARE.  The FPU
	parameter may be deleted, the default is SOFTWARE.  The CENVIRON
	variable should always be set to the appropriate values in the 
	.profile or .kshrc files."

I'm not sure if this is actually true, but if someone was able to
interface the MC68881 math acc. unit to the UNIX PC, the software problems
might not be too hard.  Of course without system source, you wouldn't
be able to recompile anything in the system to utilitize the FPU.  

Also for some other tidbits, in the AT&T UNIX PC Service and Parts
Ordering Information there is this:

	Comcode 105160253   Math. Acc. Unit MC68881

Now for the disappointing news... I spoke with someone at AT&T who told
me that they either never came out with this board, or it was 
discontinued because of the price being way too high.  I would imagine
the board was "reality" if there was a comcode.  It isn't available anymore
if it ever was.

Hope this helps in the quest for enhancing hardware on the UNIX PC!
-Lenny
-- 
Lenny Tropiano             ICUS Software Systems         [w] +1 (516) 582-5525
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