Hello! Dr Jefyll wrote: > Huh -- or maybe we CAN! The question is, are /writes/ to $0000 and $0001 > also passed on to RAM? With the present arrangement I think they are. That > means it's OK to have two bus masters later when the read occurs, because > the data will be the same! > > But is the present arrangement acceptable? I heard some discussion somewhere > about writes to $0000 and $0001 /not/ being passed on to RAM. Is that a > desirable thing? Here's where my lack of CBM knowledge becomes apparent... > :o/ They shouldn't be, because that could corrupt bytes 0 and 1 in a bank where BASIC data is stored. BASIC program area starts at $10000 not $10002 so the BASIC ROM expects that nothing corrupts the ram at $0 and $1 location. However, it is possible that these locations ARE corrupted but in the current execution bank; since the ROM code always runs from bank $F, corrupting values $F0000 and $F0001 is not a big deal. I think a test program should be written to confirm / deny this. Regards, Michau. Message was sent through the cbm-hackers mailing listReceived on 2018-02-25 13:02:13
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