Re: Tailgunner has a special monitor?

> >BTW, Tail Gunner was the only game to use JUMP EXTERNAL. Space War uses
> >it as an unconditional jump and all the other games have it wired to
> >the sign bit so it's Jump Minus (JMI). Uhhh Zonn what does Speed Freak
> >do with it? I still can't make that run without locking up :-)
>
> I'm a little confused about the "unconditional jump" use in Space War.
>
> A read once (on RGVAC) that you found this to be the case, but I couldn't
> find the jump used anywere in the code. I placed breakpoints in my emulator
> on the jump external instruction, and I never found it. I then burned some
> Space War ROMs and place them in an unmodified Star Castle board and they
> ran just fine.

So you've got Vectorbeam Space War roms eh?? The Cinematronics version
uses the jump-external instruction and assumes it always jumps. I tried
running the emulator with a patch to change these to a regular jump and
saved the images - this produced something that seemed to run OK while
emulating a Star Castle board. Someone (I think Sean Riddle?) was going
to test these on real hardware and I never heard how it went. So what does
a guy have to do to get Vectorbeam rom data? This would slightly simplify
our emulator code :-)

> Also looking at the schematic, the external input is not pulled hi or low.

Are you sure? I thought there was a pullup right near the jump condition
selector. Near the jumper that switches it to JMI.
 ___ __ _ _ _
| \ / \ | | | || | phkahler@oakland.edu Engineer/Programmer
| _/| || || |_| || |__ " What makes someone care so much?
|_| |_||_| \___/ |____) for things another man can just ignore. " -S.H.
Received on Tue Aug 12 06:41:41 1997