ADRHEXADRNAMEDescriptionshadow ofOS
623 $026FGPRIORPriority Selection Register PRIOR all

Priority Settings#

01P0-P1-P2-P3 PF0-PF1-PF2-PF3 BAK
12P0-P1 PF0-PF1-PF2-PF3 P2-P3 BAK
24PF0-PF1-PF2-PF3 P0-P1-P2-P3 BAK
38PF0-PF1 P0-P1-P2-P3 PF2-PF3 BAK
416Four Missiles add up to be 5th player
532Overlapping Players have 3rd color
664GTIA Mode see next table
7128GTIA Mode see next table
P0-P3 Players PCOLR0.../COLPM0...
PF0-PF3 Playfield colors COLOR0.../COLPF0...
BAK background or border color COLOR4/COLBAK

A logical OR is done to the colors of players 0/1 and 2/3 when they overlap. Only the 0/1, 2/3 combinations are allowed; you will not get a third color when players 1 and 3 overlap, the priorities set with bits 0…3 are applied.

If put together into a 5th player (set Bit 4 to '1') the missiles get the color of register 3 COLOR3. They still move independently, e.g. set their horizontal positions with HPOSM0 - HPOSM3

GTIA Modes#

This register can be used to select one of GTIA GRAPHICS modes 9, 10 and 11.
GTIA Mode*Bit 6Bit 7Description
90116 different luminances of the same hue (color)
10109 different colors
111116 different hues (colors) of the same luminance
* the same as GRAPHICS x in BASIC

see also: Player Missile Topics

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