All posts tagged cycles

Simple c64 interrupt

Having done some work with interrupts now, I’ve realised just how powerful they can be for demo coding and how time sensitive some effects / routines are. I’ve looked at a few different ways to set them up and thought I’d recap.

Interrupts occur every 60th of a second. On the C64, memory locations $0314 and $0315 (788 & 789 in decimal) contain a vector to the execution address of the normal interrupt service routine. The default values here are $31 (49) and $ea (234), which form $ea31.
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