You're running out of time! Or you don't know how long your game's
operations are taking.
Suck it up and learn to cycle count: learn how to know
exactly how long each 6502 operation takes.
I'll be honest: in general, I wasn't as pressed for time
as I thought I would be through most of my own Atari game.
The big exception to that, of course, is "the kernal",
the part of the game that's active when the TV picture is
You have exactly 76 machine cycles per scanline, and most
assembly instructions take 2-6 machine cycles. If you're really
macho, you can learn to time things so exactly that you don't even
have to WSYNC.
Nick Bensema's Guide to Cycle Counting stands as the canonical (and readable!) document on the subject. That's
probably your best bet, along with asking [stella] for specific kernal-optimization ideas for your problems.
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