I just happened to notice this in the manual:
Edit: And even in the manual's example of a DFS *LOADing into sideways RAM, wouldn't the actual writes be done by NMI code executing in page &D, rather than code executing from the DFS ROM directly? Maybe the NMI code would page the DFS in and execute code from there though, I'm definitely no expert on this.
This matches what tricky pointed out earlier, and rather disappointingly seems to add a caveat to the bit I quoted before. If this *is* Marcus's board (and it does seem like it is), there must be more to it than this makes out because as I say, Ozmoo will be poking into sideways RAM from code executing in main RAM and yet Ozmoo is working. I suppose it depends what "accesses come from" means. If having ROMSEL selecting a ROM on the board is enough, that would account for it.In use, the two RAM sockets (14L and 14H - logical socket 14/&E) are only active when accesses come from on the ROM board.
Edit: And even in the manual's example of a DFS *LOADing into sideways RAM, wouldn't the actual writes be done by NMI code executing in page &D, rather than code executing from the DFS ROM directly? Maybe the NMI code would page the DFS in and execute code from there though, I'm definitely no expert on this.
Statistics: Posted by SteveF — Thu Oct 24, 2024 10:33 pm