Re: RFC : SOME IDEAS FOR THE APPLE II FPGA'ers

["Michael J. Mahon" <mjmahon@aol.com>]

mdj wrote:
> Michael J. Mahon wrote:
>
>
> > > I think for the most part, it would work, but be of limited utility as
> > > you break compatibility with other 6502 systems. It'd be better to
> > > implement the 65802 or 65816 in that case and use it's superior stack
> > > handling abilities.
> >
> > And look at all the great software that runs on those platforms...  ;-(
>
>
> Merlin 8/16 ;-)
>
> Just pointing out that if you want to improve the 6502 design to run
> more sophisticated software, it's already been done.

True.  And I was pointing out that it was mostly a big yawn.

> > Put another way, if you're emulating all the peripherals, why not
> > just emulate the system itself?  Exactly what "authenticity" of
> > implementation or experience is being preserved?
>
>
> I don't want to emulate the peripherals. I just 'fancy' the idea of
> having working, useful ethernet and USB on such a board, so as to
> simplify software transfer (This coming from someone who's Apple IIe
> has a Workstation Card + Asante ethernet adaptor connected permanently
> to the home network + superdrive for sneakernet transfers)

Sure, but what about all the *existing* Apple II peripherals?
Does my Quickie scanner get emulated?  My stepper motor control
card?  See why I want the peripheral bus, and why I consider all
the other stuff "emulated"?

> I  like the idea of an extension to the system to virtualise 5.25"
> hardware, allowing the permanent archival of all my 5.25" media and
> drives.

Depending on the depth of virtualization, that could be either
a tall order (quarter-track spirals) or a snap (CFFA card).

> > With a little specialization of the RISC core, you could go at
> > *ludicrous* speed.  ;-)
>
>
> Maybe. I doubt you'd get it to go appreciably faster than a synthesised
> 6502, and you'd have to clock it a lot harder to achieve similar
> results. Not my preferred 'solution'

I *was* kidding with that remark.  I fail to see the purpose
of running an Apple II more than 20x its design speed.  ;-)

> > Right!  It's important to me to have my 2000-line assemblies done
> > before I can get my finger off the RETURN key...  ;-)
>
>
> I wrote a mathematics package in Apple Pascal many years ago, and the
> compile/link time was tedious. On my current Apple IIe, watching the
> same thing build is still tedious, but then I only have a Transwarp,
> not one of the ooh-ahh 8Mhz Zip fandangles :-)

An 8MHz Zip Chip is worth about 5MHz on typical compute-bound stuff...

> Seriously, anything worth doing on an Apple II is going to end up I/O
> bound at much more than the speed we can achieve today with the
> 'better' accelerators. (I consider the Transwarp superior to the
> alternative I have, a Zip 4Mhz, except for the heat it generates)
>
> I mean, it's not like we're going to be playing mp3's 'in the
> background' with all the spare CPU horesepower ;-)

Right.

> > Now, playing with emulating an Apple II to learn FPGA's and digital
> > design is a *great* motivation.
>
>
> Agreed. Learning something new and stimulating the mind is the entire
> point of the exercise.

Outstanding!

> > But what are you guys doing with your Apple II's that causes you to
> > get bored waiting for it to finish, anyway?
>
>
> Writing an Operating System, and not getting bored waiting for it to
> build. The assembler runs quite fast enough for me a 3.6Mhz, and my
> hard disk running via my Rev C. SCSI card.

Yes, I regularly assemble a few thousand lines with Merlin 8 Pro, and
with the screen listing turned off, it does it in seconds, not minutes
(with an 8MHz Zip Chip).  That's fast enough that I don't get out of my
chair.  ;-)

-michael

Music synthesis for 8-bit Apple II's!
Home page:  http://members.aol.com/MJMahon/

"The wastebasket is our most important design
tool--and it is seriously underused."