[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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