[Coco] Assembly GIME programming...
zmerch at 30below.com
Mon Jan 23 17:41:04 EST 2006
Rumor has it that Robert Gault may have mentioned these words:
>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
> 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
Roger "Merch" Merchberger
Roger "Merch" Merchberger | "Profile, don't speculate."
SysAdmin, Iceberg Computers | Daniel J. Bernstein
zmerch at 30below.com |
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