[Coco] Assembly GIME programming...

[Roger Merchberger]

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

>Registers $ff9d and $ffde are the 16 bit vertical offset.

*that's* what I needed. I had no idea:

"16-bit vertical offset" == "start of video memory"

;-)

>This pointing only needs to be done if you start your ml routine from a 32 
>column screen.

>  If you enter WIDTH80 before starting your ml routine, the registers are 
> already correctly pointing to the high res text screen.

Eventually, I'll be starting it from "Blank Slate." The closest I can come 
to that right now is from the 32-column screen, but eventually, I'm 
building a CoCo3 with a totally different ROM running an OS called Cubix 
from Dave Dunfield... which is why I won't have access to any of the ROM 
routines. This may eventually get backported to a CoCo2 w/64K, but going 
back to a 32x16 for any serious amount of time just seems... painful. ;-)

I already have the "hackable" CoCo3, I have enough good tools to replace 
the ROM and maybe the CPU socket with a ZIF socket [[ Just in case a 6309 
just *happens* to drop into my lap... ;-) ]] and now that I'm starting to 
get used to Portal-9, some good development tools as well. That, and an AT 
keyboard adapter that I'd like to design & build (I just happen to have a 
couple spare AVR8515's about...) but that's for a later date... ;-)

Anyway, thanks for the info - that should give me more than enough to get 
started...

Laterz,
Roger "Merch" Merchberger

--
Roger "Merch" Merchberger   | "Profile, don't speculate."
SysAdmin, Iceberg Computers |     Daniel J. Bernstein
zmerch at 30below.com          |