At 09.06.2002, 13:10, Fabrizio Zavagli wrote:
> About the asymmetrical playfields, there's something I don't really
> understand about it.
> I was modifying the above-mentioned sample to squeeze and slightly optimize
> it and decided to use the Y register instead of memory.
> When I've implemented Y, I started having some garbage (black vertical
> lines) on the screen when re-writing to PF0...
> snip
> As you see, I've just replaced ScanPix with the unused Y register... that
> should take less cycles and memory.. but I get that weird artifact!
> Actually I get the artifact whenever I write to the Y register..
If you don't find a bug inside the code, you should check the timings.
Probably a hidden page-crossing cycle is causing that problem.
Where exactly are the artefacts? And how do they look like. The best
would be to post the code and/or a binary.
Have fun!
Thomas
_______________________________________________________
Thomas Jentzsch | *** Every bit is sacred ! ***
tjentzsch at web dot de |
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