Re: Tailgunner has a special monitor?

At 09:45 AM 8/12/97 -0500, you wrote:
>> >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 :-)

The ROM data I found on the NET matched my version of Space War, either way
I'll send you an E-mail package, (I'd use UPS, but the strike and all...)
>
>> 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.

I was really sure until I read this sentence. I went over this pretty
carefully wondering how Cinematronics could justify using the JEI (Jump on
External Input)
instruction, without risking crashes and I couldn't find a pullup. But as I
said earlier I never checked the sound card.

Of course now I'll have to go home and check the sound card & the CPU, I'll
let you know.

-Zonn
Received on Tue Aug 12 10:21:18 1997