Re: ti92 programming?
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Re: ti92 programming?
On Thu, 18 Jul 1996, P. Kolbus wrote:
>>Problem is, the TI92 really cant be programmed in assembler unless you figure
>>out how to get around the OS...which the fargo programmers obviously
>>succeeded
>>in. I'm going to try as soon as I get a cable, but it may take a while or not
>>work at all... and all this can be avoided by sharing some few lines of info.
>>
>>I would at least want to know how the screen is adressed, so I can start
>>writing a game on amiga and download it when fargo is released.
>>
>>//Jonas
>>
> This seems to be the key... There is a bug of some sort in the Graph-Link
> utility (or in the calc link, I don't remember) that if you send a backup
> that is too large, it cycles back to the beginning of memory after reaching
> the end. Using this, you can rewrite the registers and interrupt vectors. I
> don't have a '92, nor do I know the internals of the 68000 or assembly
> language, so I cannot work on this. If you know the 68000, you should not
> have any trouble making a Fargo clone...
>
> There are two problems with this approach, though. First, the calc jumps as
> soon as the register is overwritten, and second, the backup is ROM-version-
> specific.
I know a bit about the 68000 since I've been hacking the amiga for around 5-6
years now. Thanks for the info, I will certanly try to abuse this feature as
soon as I get a cable ready (tomorrow hopefully!). I have v1.4 of the
TI92 rom which (I think) is newer than the guys developing Fargo has (v1.3).
I hope they haven't corrected the bug...
//Jonas
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