[Coco] CoCo 3 MMU test for all

Roger Taylor operator at coco3.com
Sun Jan 20 21:02:54 EST 2008


At 07:43 PM 1/20/2008, you wrote:
>Roger,
>
>You must be still sleep deprived or you don't understand the GIME.

Thanks, Mark.  :)  I'd have to lean towards me needing a nap, which I 
just woke up from.

You say $0-$f is for a 128k CoCo, so why are blocks 48-63 used within 
BASIC?   56-63 are stored in the TASK 0 64k map.



>I always thought programmers did it in hex? I know hardware designers do!

I'm a decimal + hex guy, using both randomly depending on the mood 
I'm in.   Believe me, I realize the frustration to other coders when 
I post decimal values.  Robert Gault probably pulls his hair out 
every time we have a technical chat.




>Per your table below. You can't look at it that way. Bits 6/7 ARE 
>NOT READABLE. That is why you AND out bits6/7.
>
>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)

The table was a "maybe this is what's really happening, and not what 
I've believed has been happening all these years".  I didn't post the 
table as a guideline.  It was more of a question than the answer.

I always use 48-63 on a 128k CoCo.  I don't read back the MMU 
registers.  I make my own values and write only.  I realize the upper 
2 bits behave this way and is why I'm trying to gather more 
information so I can pull off a LOADM trick.






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