Hello! A.Fachat wrote: > That brings me to the question - what is the memory layout of the hires > mode? That should give us some more hints... OK, here are first results of my ROM disassembly. So far I looked at a routine at $883F which apparently is used to perform various graphics tasks. First of all, the routine banks out the ROMs with these instructions: lda #$83 sta $E888 The address $E888 is in the CRTC register space. Apparently the board intercepts this address with some latch on its own. This latch most probably drives the values of jumpers JU1-JU7 (as you can see on my photo, these jumpers are replaced with a connector that goes to the video board). The routine then reads a command number that is apparently stored at $03A0, and depending on that it does different things. The number #$07 is apparently an initialization code, which stores zeroes in $A000-$DFFF. So this is most probably where the video data resides. Finally the procedure restores ROMs with these instructions: lda #$0F sta $E888 These are the only accesses to the $E888 register in the whole ROM. I will proceed with analysis on how the actual video data is organized. Regards, Michau. Message was sent through the cbm-hackers mailing listReceived on 2012-10-02 21:00:06
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