[Coco] CoCo 3 MMU test for all

[Robert Gault]

Mark Marlette wrote:

><snip> > 128k: 112-127  s/b 0-$0f
> 512k: 64-127   s/b 0-$3f
> 1 meg: 64-255  s/b 0-$7f
> 2 meg: 0-255   s/b 0-$ff  (only one you got right, think hex, it is easier)
> 
 ><snip>

And with Paul Barton's 8-Meg board, bits were added from another I/O byte.