From: Michiel Boland (michiel_at_boland.org)
Date: 2005-02-17 09:33:30
Now that the VIC article has come up again, I am curious if anyone has done any research into the following. If you remove the side borders on a C64 and put any of the sprites 1-7 at X-position 356, or any position >= 356 "before" the data fetch for that sprite begins, the sprite is moved up one pixel vertically and the first line contains apparent garbage rather than what is supposed to be displayed. In the top line, the second byte appears to be read from $3fff, and the first and third bytes are $ff. Anyway, this is what the VICE emulator does. But in real life, things appear to be a little more complicated. The first and/or third bytes contain something other than $ff, depending on how many sprites are active at that time. Who has any clue as to where these bytes are fetched from? Cheers Michiel Message was sent through the cbm-hackers mailing list
Archive generated by hypermail pre-2.1.8.