[Coco] ML Question: MMU Block Switching

Robert Gault robert.gault at att.net
Tue Feb 17 20:37:15 EST 2015


William Mikrut wrote:
> Thank you Robert.
>
> I am playing around with this some more tonight an I want to go into the
> unraveled document and look at how LPOKE specifically sets registers for
> execution.
>
> If i interpret what you are saying, FF9D/E just remaps vidram to a
> different starting address in high ram.
>
> I still need to load the MMU with that page to read/write data to that
> location... but could easily offset the default of 6C000 with the example
> you listed above.... or to any place in High ram as long as the MMU was in
> sync with the address block I selected.
>
> Sorry if I am such a noob at this, but I have wanted to learn these things
> for a LONG, long time.
>
>

The video pointer and MMU registers are completely independent. The only time 
you need to change an MMU register is when you want to read/write to memory in a 
specific MMU block.
Put another way, video will be displayed (hi-res Coco3) where $FF9D/E point 
regardless of the MMU values.

Robert



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