Tuesday 20 October 2009

Disassembling Jaguar Games...

...is a long and convoluted process it seems!

The best source for all things Jaguar I have found is the Jaguar Sever Homepage which contains pretty much everything a budding Jaguar hacker could hope for, unfortunately though if you're running 64-bit vista or windows 7 then hoping is about as far as it gets.

Sooo it goes a little something like this:

The Jag has three main processors, Tom, Jerry, and a Motorola 68000 who was picked on unrelentingly for his silly name. Srsly though, Tom contained the main dedicated GPU, in addition to the 64-bit object processor, and blitter chip (which is where the 64-bit ends). Jerry did all the bitch tasks like sound and Input whilst also being available for other non-specific stuff if the occasion called for it.

The 68000 was, and still is, a general 32-bit control processor.

This gives us quite a few disassembly options; however...While Atari ranted on about how developers could use the 64-bit blitter for all their logic processing needs this turn out to be a tad more involved or at least non-deadline-compatible than game devs at the time cared to be complicating their lives with. Consequently most game logic was processed on the 68000. 

For the sake of interesting times in assembly I decided to attempt to disassemble some of the 68000 code. 

If you are really eager and have already clicked on the Jaguar Sever Homepage link up there you'll notice the only option for 68000 disassembly seems to be a program called "easyrid4", which 'runs with' a Jag emulator (?); well it certainly wasn't content to run without one... The emulator Pacifist being the only suggested option I install it and discover that I am not DOS and that this just doesn't sit right with it. Not being one to give up that easily I crack open the DOSBox (a DOS emulator) and then attempt to emulate my emulator (ha)... Ultimately I am met with some variety of 'deferred success'.

I think I'll wait till I regress into a nice retro-friendly OS before having another stab at this, in the mean time there are plenty of  more popular retro consoles to satiate my disassembling desires.

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