Re: ROM Editing & Prize Offer

["Paul Grammens" <grammens@svn.net>]

"Michael J. Mahon" <mjmahon@aol.com> wrote
>
> S-C Disassembler is a good one in my experience.
>

Reading thru the docs on that, it seems like it doesn't support code for the
65C816 used in the IIgs.  It only mentions the 6502 and 65C02.

> BTW, Bob Sander-Cederlof is the author of the AE firmware,
> as well as the noted S-C Assembler and the Disassembler.
> He went to work for AE after gaining considerable acclaim as
> an Apple assembly language expert.
>

I looked thru the binary of the Vulcan's EPROM with a hex editor, and the
only ASCII I saw was Bob Sander-Cederlof's name and copyright.  Searching
for him on the net led to the S-C Assembly software, which he has now kindly
released as freeware. His home page doesn't mention working for AE, though
it does have a lot of bio info.

> I think that several folks, myself included, would be interested
> in a good disassembly of the Vulcan code.

I'm afraid you're unlikely to get it from me. I took a stab at it, but
concluded that the learning curve was too steep. I hoped that I could just
compare the binaries of my 40 meg and 20 meg Vulcans and figure out a couple
of numbers to to patch, but no dice. I'd like to either make the changes so
that many IDE drives could be used, or failing that, make a variety of
EPROMs that could be used to support a variety of drives. Like if you could
just change three numbers for Cylinders, Heads, and Sectors per track to
match the drive you wanted to use, then burn the EPROM, that would be good
enough.

I took a shot at it
> many years ago (when my reverse-engineering skills (or maybe
> my patience  ;-) were not so developed, but didn't complete it.
> I do remember being impressed at the unrolled loops used for
> moving data from the onboard buffer to Apple RAM.
>

You're way ahead of me.  I did find a disassembler for the Super Nintendo
(SNES) called DSFX131.zip. Apparently the SNES also used the 65C816.  Next
time I see one at Goodwill I'm going to buy it and open it up. Maybe it has
some useful parts.
I was able to run DSFX on the Vulcan binary, but assy language is gibberish
to me.

I'll offer a nice Apple IIc+ or Apple High Speed SCSI card to anyone who can
disassemble the Vulcan EPROM and modify it to work with other drives. I can
supply the binaries to work on, and I'll ship the prize free to the winner.
If you can do this, but want something else, let me know. Perhaps I have it.
-Paul