>>>>> "Zak" == Radioactive Warrior <firstname.lastname@example.org> writes: Zak> Hi all, I am trying to find out what the 6510 sees at addresses Zak> $1000 - $7FFF in "ultimax mode". My code kept crashing when I Zak> tried switching into ultimax mode (I had the ML at $2000) Makes sense. Switching to ultimax mode makes everything between $1000 and $7FFF disappear. Zak> and as soon as I moved the ML to $0F00 (toggling /EXROM & /GAME Zak> with an external latch at $DE00, ala super snapshot) it worked on Zak> the first go... What decodes ULTIMAX addresses, the PLA? Yup. Zak> Could someone list how the PLA behaves when /EXROM = 1 & /GAME = Zak> 0 ??? The c64 PRG does a piss-poor job, as per usual, of Zak> explaining it saying only $1000-7FFF and $A000-CFFF is "OPEN" in Zak> ultimax mode. Open means that nothing is answering at these addresses and you'll only get bus noise if you try to read from it, like $DE00-$DFFF behaves if you don't have a cartridge plugged in. So in ultimax mode you have 4K of ram at $0000-$0FFF 8K of cartridge rom at $8000-$9FFF 4K of I/O registers at $D000-$DFFF 8K of cartridge rom at $E000-$FFFF The rest of the address space is unusable (unless you're Marko Mäkelä :). -- ___ . . . . . + . . o _|___|_ + . + . + . . Per Olofsson, konstnär o-o . . . o + MagerValp@cling.gu.se - + + . http://www.cling.gu.se/~cl3polof/ - This message was sent through the cbm-hackers mailing list. To unsubscribe: echo unsubscribe | mail email@example.com.
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