[Color Computer] [Coco] ASM Coders - Round two!

[Mike Pepe]

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.

-Mike