[Color Computer] [Coco] ASM Coders - Round two!
lamune at doki-doki.net
Wed Aug 30 12:57:46 EDT 2006
L. Curtis Boyle wrote:
> This was actually a fairly common technique, which a lot of us
> referred to as "stack blasting" (Steve Bjork is the first person that I
> know who used that term). Just off the top of my head, the XMas GRFDRV
> patch from Kevin Darling, et al used it for screen scrolls, Flight Sim
> II used it to draw each half of the screen, and Biosphere used it for
> scrolling as well. Only problem is is that you have to shut interrupts
> off to prevent IRQ's from dumping garbage onto the S stack that you just
> reprogrammed as either your source or destination pointer (one of the
> reasons that the 6309 patch for Flight Sim II using TFM helped modem
> users so much... it originally stack blasted a large chunk of the screen
> on every screen update, with IRQ's shut off the whole time).
Hey, that's a cool idea. If you didn't disable the interrupts, you could
"see" the stack!
I should try that! I never saw the stack before.
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