[Coco] Assembly GIME programming...

[Roger Merchberger]

Rumor has it that Robert Gault may have mentioned these words:

>The high resolution text screen is located at $6C000-$6E000 if created by 

>the Coco ROMs.


Yup. My problem is with what I'm doing, I can't use the CoCo ROMs. ;-)


>  If that is the region you want to access, first decide where in your 64K 

> of RAM you want it to appear, use the appropriate MMU registers for that 

> RAM region, make sure that $FF90 is set for Coco3 mode and the MMU is 

> enabled, and make sure that the IRQs are off when moving around memory 

> until it is reset.


I got that far - I got the machine out of CoCo2 mode, got the 80-column 
screen set & mapped in $6C000-6DFFF into an unused portion of memory -- 
what I don't know and can't seem to find is how to tell the GIME where I 
want it to use video RAM from - as it seems it defaults on boot to thinking 
it should start at $70000 (as I can see the text at $70400 in the 80-column 
screen).

I went thru the CoCo3 TechRef that I have & Sockmaster's GIME page on the 
'net, and other than my sheer stupidity (which is certainly possible! ;-) I 
can't seem to find what registers tell the GIME where in RAM to start the 
80-column Video RAM. :-/

When I get home, I can post the assembly code I have so far...

Thanks,
Roger "Merch" Merchberger

--
Roger "Merch" Merchberger   | "Bugs of a feather flock together."
sysadmin, Iceberg Computers |           Russell Nelson
zmerch at 30below.com          |