Re: vcs.h (was: Re: [stella] redline problem OK...THANKS!!!!)

Subject: Re: vcs.h (was: Re: [stella] redline problem OK...THANKS!!!!)
From: Chris Wilkson <ecwilkso@xxxxxxx>
Date: Fri, 19 Jul 2002 17:18:45 -0400 (EDT)
On Sat, 13 Jul 2002, Eckhard Stolberg wrote:

> > Yes, I did make it up.  But that doesn't make it any less valid as
> > a hardware format.  :)  I'm the first to admit that it's vaporware,
> I wasn't trying to put down the Megacart format. I was just
> using the fact that you misspelled it as "Mecacart" as an
> excuse for not having to implement support for it in z26. ;-)

Well, even if you's fair and expected!  :)  This is a
great example of "vaporware".  I completely missed the misspelling.
Twice.  I've been tooling like a mad man to get all the carts and
kits for CGE shipped.  I just realized last night that I'll have
hardware in 5 of the 2600 releases this year.


> No matter how many emulators support the Megacart format, I don't
> think you'd get any programmer support unless you can prove that
> it works in hardware and that you can provide boards in quantity
> at a reasonable price.

I agree.  The target for low quantities would be $15, but I think I
can get it under $10 for larger quantities.  Still, that's pushing
my personal limit for too expensive.  I had it working a few years
back in ROM only form.  The RAM was flakey, but that's because I was
being a cheapskate and refusing to add a clock. :P

> I mean everyone around here always complains
> that 128 bytes of RAM aren't enough for his game, but no-one dares
> to write something for the countless extra-RAM formats that the
> emulators support, because there isn't a ready-to-use way to get
> such a game released in cartridge form.

Yeah...same old story.  If I hadn't been hit with waaayyy too much work
this summer, I was going to try to demo one at CGE.  But it's just not
going to happen.  :(  But it looks like I've got a ***BIG*** block of
time coming after the show.  Woohoo!

> Under DOS you get memory in segments of 64K. If you want more
> memory, you need to mess around with the segment registers. Since

Got it.  ^@@!#$%!! segmented memory!  What a stupid idea.  Grrr!!!!
I hate computer history.  So many bad decisions.  So many poor designs
that became standards.  Sigh.  That's why I deal with game consoles.
No such sad history in this field!  :P

> Or we could copy the entire bank from the other segment to the
> main data segment every time the game switches a bank. This
> it what we do for the Megaboy ROM. Since the Megaboy accesses
> it's banks sequentially and doesn't do too much bankswitching,
> this is working quite alright. But for a game with lots of random
> banks accesses this method would probably quite slow and the code
> to support it would be pretty ugly. So support for the Megacart
> in z26 isn't impossible. It just wouldn't be nice enough to write
> it without a good reason. ;-)

I was going to suggest this, but also had speed concerns.  Maybe you
could use the high order bits of the MegaCart's slot registers to key
to the segment registers?  It might be a little wasteful of PC memory,
but it could work.

At any rate, I can see why it's a pain.  Maybe there will be hardware
with some working demo code by the end of the year.  Then I expect a
couple of long talked about ports to be attempted.  Whee!


Archives (includes files) at
Unsub & more at

Current Thread