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

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

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.

> 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)

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.

> 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'

> 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 :-)

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 ;-)

> 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.

> 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.