Quote:
Originally Posted by Snoopy1234
No expert but kickstart 1.2 included timer.device in rom that checked the Pal/Ntsc status of the amiga and updated timing and screens accordingly. 1.1,1.0 didn't have this and seperate PAL and NTSC versions were released.
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The game takes complete control of the system, so no matter which kickstart you use, the behavior is always identical.
But I checked the code: the IRQ3 handler is very dangerous (and in fact it crashes
).
So is this: "
Maybe in NTSC it try to finish something with 000/7MHz in one frame and there isn't enough time."
Basically it lowers the priority during the management code to allow IRQs of the same priority (by Copper) to be executed anyway, as if they were of higher priority, interrupting the one being executed (VBI).
The problem is that the executed code requires more video lines than those available in NTSC and the new VBI is executed recursively within the previous one, generating a wonderful stack overflow (and since the SP is in low memory it quickly overwrites the exceptions vectors).
This explains perfectly why in NTSC you have to have a 68000 >7MHZ or a 020+
