RE: mmu for 65c02

From: Baltissen, GJPAA (Ruud) (ruud.baltissen_at_abp.nl)
Date: 2005-04-21 15:18:24

Hallo Gabor,


> I was writing about a theoretical system not a C64 ;-)

I know, I only used it as an example to emphasize the need of saving the
contents of various registers. And the I/O port is a good example IMHO.
Saving the contents of the SID or VIC in a multi-tasking enviroment is less
obvious.


> I mean if a memory area is write protected, ....

Ah, good idea! 


> Even the read can be denied by simply eg read always
> zero if page is not readable by a process. 

Even better! And zero is the code code for BRK which means that even an
illegal jump is intercepted. I really learned some nice things today :)


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