Re: mmu for 65c02

From: Jim Brain (
Date: 2005-04-29 00:17:06

A. Fachat wrote:

> fachat wrote:
>> On Tue, Apr 26, 2005 at 11:17:53PM -0500, Jim Brain wrote:
>>> The only thing I think of doing is to stretch the cycle during a 
>>> page fault to the maximum allowed and use another processor to do 
>>> something during the time you have.  Or, if the processor is static, 
>>> simply stop the CPU and use another to map the page in.   
>> Yes, I think this is the only way. Only for the 6502 you have to queue
>> the write accesses as they cannot be stretched, right?
> Just got another thought - you mean not to stop the CPU with "RDY" 
> (like I thought) but to
> really make the clock cycle longer, stretch it? Maybe that would do 
> it, although I doubt

Yes, that was my thought, and yes, there is probably not enough time to 
page RAM in from disk.  If all that was needed is to page another bank 
of RAM into the limited address range, you might be able to stretch long 
enough to do that.


Jim Brain, Brain Innovations                      
Dabbling in WWW, Embedded Systems, Old CBM computers, and Good Times!

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