I'm using Aaron Giles' port of Stella 0.7 on a PowerMacintosh.
I've also ported Dillon's "DASM" to MPW (look for it on Mactari's web site), and
even spiffed it up with Commando help interfaces, etc. [I've given it to
Mactari site owner - it's up there]
Now, I've built some ROMs (nbcombat was my first, worked like a charm first
time).
I then went on to clock003.asm (a demo written by Chris "Crackers" Cracknell) --
I find it doesn't work when I compile it straight w/o modifications. Stella
says it executed an illegal instruction, I may need to setup the cartridge type,
blahblah. As provided, it's a 4K ROM image, which I was under the impression
that Stella auto-detected and configured itself properly to handle that sort of
thing. (Note: the file size was exactly 4096 bytes, and had the right things in
the right places, reset vectors, etc).
Well, I changed the ORGs so as to make it a 2K ROM ($FFxx->F7xx basically) and
it worked it perfectly.
Question is.... WHY? I touched no code at all. Just the ORGs. It was
otherwise identical, except for it being 1/2 the size.
I also tried to setup a stella.vcs file in the same directory as Stella itself,
no dice (with the 4K image) -- I explicitly set the Cart type to 4K, fiddled
with the 6507 strictness flag, the works. It would refuse to accept the binary
image.
Note: I did compile each of these with my ported DASM with the -f3 setting.
It's also worth mentioning that nbcombat.bin is a 2K image also.
Is there a problem with running compiled .BIN images larger than 2K on Stella?
Is there some piece of magic I need to put in the images themselves for them to
load properly?
=Rob=
------------ Message 2 ------------------
Does MacStella 0.7 allow stella.vcs files? I've been playing around with
building my own cart images, and find that sometimes carts don't work (wrong
auto-detect) at certain sizes. For instance, I compiled Cracker's clock003.asm
out of the box (with DASM, which I've ported to MPW btw, FAT with a Commando
interface and all), Stella says it's the wrong cart type, blahblah. I change
the ORG statements to make it a 2K image, and Stella runs it happily.
ARGH. Did Aaron pull support for stella.vcs settings files? Could I have the
source to resync it w/normal Stellas? Please don't remove it -- for 2600
hackers like us, we'll need the functionality for quite some time. Even if you
embed it into a big TEXT resource or something. Just let us have manual
controls over cartridge detection!
=Rob=
---------- Message 3 --------------------
I guess MacStella "checksums" the ROMs, and uses a built-in table. Its checksum
must be "weak" since it mistook my clock003.bin rom for something that evidently
had a different memory layout.
When I manually defined some random junk in the rom image (outside of needed
code or data) it worked fine. It's a "mis-correspondence" of ROM type via a
flawed checksum algorithm, not a codegen issue at all. *SIGH*
Aaron! We need stella.vcs access for MacStella!!
=R=
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