RE: Building my monster C64 accelerator

From: Baltissen, R (Ruud) (
Date: 2003-08-20 08:25:11

Hallo Oliver,

> Yeah, but wouldnt this actually kill the i/o space in the 
> other banks? 

Yep, that is, outside the first 64 KB area.

> This would also kill the idea of having the virtual C64s...

No, not at all. See it as putting a EMS-card into a PC-AT. You have _and_ 16
MB normal lineair space _and_ ?? MB RAM wich is accessible in blocks as big
as 64 KB. In C64 language: 512 KB in the first 64 KB area and then another
255 64 KB-blocks lineair area for RAM and/or extra I/O.

My idea has even a big advantage. I upgraded my C64 once to 256 KB. This
meant extra I/O to tell the circuit what bank to, what the common areas were
etc. And whatever configuration or addressrange you choose, it will always
conflict with one or another program and/or cartridge. My idea gives you the
possibility to place the needed I/O _outside_ the first 64 KB bank. This
simply means that only a dedicated 65816 instruction can access this I/O.
And no normal C64 cart or program can do that.

But, please tell us what idea you had in mind? I tried thinking of several
altenatives but all had at least one disadvantage: the needed I/O was
visible for all the virtual C64.

   / __|__
  / /  |_/     Groetjes, Ruud
  \ \__|_\


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