On 5/25/2013 4:30 PM, Michał Pleban wrote: > Hello! > > Jim Brain wrote: > >> Not to take this too far off topic, but I would be interested in an idea >> that would allow the ROM areas to be "banked" in such a way that you >> could fit 16kB of KERNAL or BASIC into a 8kB space. I know the trivial >> is to use a "secret" location, but that's too simplistic. I was >> thinking of something where a sequence of address accesses would trip >> the bank, and then if there was an IRQ when in the wrong bank, any >> access to the normal locations would "trip" it back by writing to a >> single location. That way, accesses to ROM routines would incur no more >> than a few cycles to flip back to the correct bank. > How would you like to return to the previous ROM bank upon exit from the > interrupt handler? You can't detect a RTI instruction because the 6510 > doesn't have the SYNC pin. > > Regards, > Michau. > > > Message was sent through the cbm-hackers mailing list To be honest, I was struggling with that. I could see watching the vector locations for a key to snap back into regular ROM mode, but I have no idea about returning to the previous bank. -- Jim Brain firstname.lastname@example.org www.jbrain.com Message was sent through the cbm-hackers mailing listReceived on 2013-05-26 20:02:54
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