On Mon, 22 Jan 2001, MagerValp wrote: > RB> Thanks for all who answered. Reading the answers I have the > RB> feeling that my question is misunderstood. Maybe I can ask it in > RB> this way: How does the Super-CPU manipulate the I/O registers of > RB> the original 6510 at the addresses $0000 and $0001? > > Dude. Yes, how the hell does it do that? :) Does it need to do that? JiffyDOS doesn't support the tape drive. So, the only reason for accessing $0000 and $0001 is altering the status of the CHAREN, LORAM and HIRAM lines. This can be achieved (to some extent) with the -EXROM and -GAME lines on the cartridge port. If the SuperCPU really boots up the 6510 before halting it and giving all control to the 65816, it can write something to $01 that allows the SuperCPU to control the memory configurations. I think that the only thing SuperCPU needs to control is whether writes to $d000 go to RAM or to the I/O area. The SuperCPU doesn't need to read anything from the C64 RAM or ROM; it only needs to read from the I/O space. [Oh, now I see that Nicolas Welte wrote basically the same answer.] BTW, I managed to sort out most of the /pub/cbm/incoming.old files on ftp.funet.fi. The remaining files are for the PET and a collection of plus/4 games in disk images. The new uploads (since about 1998) are roughly 8 megabytes, half of which is for the c64. Marko - This message was sent through the cbm-hackers mailing list. To unsubscribe: echo unsubscribe | mail email@example.com.
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