Hello! The second portion of wisdom from the ROM disassembly :-) The routine at $8C1A initializes the CRTC into graphics mode by modifying some of its registers. The modifications are as follows: * Register $01 (horizontal displayed) = #$20 * Register $02 (horizontal sync position) = original + #$02 * Register $06 (vertical displayed) = #$20 * Register $07 (vertical sync position) = original + #$04 * Register $0C (RAM address high) = #$02 As you can see, the registers are set up for a 512x256 bitmap (because the CRTC "characters" are 16x8), sync pulse positions are shifted to better position this bitmap on the screen, and display address is changed. I suspect this change also turns on graphics display - I will verify it in the afternoon because right now I don't have access to the machine. Regards, Michau. Message was sent through the cbm-hackers mailing listReceived on 2012-10-04 09:00:04
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