[Coco] Coco 3 Memory Map Questions

William Astle lost at l-w.ca
Tue Feb 9 14:40:59 EST 2016

On 2016-02-09 08:39, Barry Nelson wrote:
> Really? A 64 column screen? Where? How? Where can I find the info? I have never hear of this.
>> To cap it off, there are bits that are not listed in the "usual" places,
>> like the "64 column 'VDG' screen" I wrote about some years ago on the list.

There's actually two different 64 column screens in the coco3. There's 
the standard "official" high resolution 64 column screen that works just 
like the 40 and 80 column screens (though it is not supported by the 
WIDTH command - you have to set it directly in the GIME). The bit 
patterns for setting it up should be listed in regular GIME references. 
Note that there is also as 32 column "high resolution" text screen 
(distinct from the "WIDTH32" screen).

The one I was referring to is having things set up for the 32 column 
"SG4" screen and then setting a specific bit in one of the GIME 
registers. It's not nearly as useful as it sounds. It looks like an 
accidental effect of some aspect of the GIME internals. If you search 
around in the list archives you should be able to find the messages 
about it.

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