Re: Innovative Systems FPE...

[mdj <mdj.mdj@gmail.com>]

On Aug 12, 7:20 am, "Michael J. Mahon" <mjma...@aol.com> wrote:
> I recently acquired an Innovative Systems (iS) 68881 FPE.
>
> It was clearly designed to accelerate SANE on the IIgs, but it
> also came with Appleworks 2.0 patches (for it's SANE routines)
> and with a set of macros for direct use with 8-bit Apple II's.

Are they SANE compatible macros? It seems wierd that they'd patch the
SANE runtime and use broken macros when SANE itself already supplies
them (albiet only for EDASM).

> Upon reviewing the macros converted for Merlin, it's apparent
> that they were never used or tested, since they have numerous
> errors.  They also suffer from the delusion that floating-point
> numbers should be represented in little-endian form on the 6502,
> which Applesoft contradicts.

Curious, since the 68k is big-endian, but I suppose you can load the
registers more quickly on an 816 that way...

> Does anyone know how many of these things were made, and if
> anyone ever used one successfully with a //e?  My serial number
> is 890005, so I'm guessing they weren't very popular.  ;-)
>
> I'm making progress, but feel like completely redesigning
> the macros to use a small runtime FPE package.  A further
> out possibility is making an interface to Applesoft, since
> the 12MHz 68881 clock compensates for the relatively weird
> dance one must do with the 6502 to load operands, perform
> instructions, and store results.
>
> This might be a more interesting thing to do if there were
> more of them in use...

Well, if you managed to make a patchset for Applesoft and somebody
wanted to produce some , it'd be a mighty fine accelerator
companion... How complex is the board ?

Matt