[Coco] A question for the (Nit)OS9 Developers

[jdaggett at gate.net]

Boisey, Aaron, and anyone else that can explain

I am looking at some of the source code to get a bit of understanding how OS9/NitrOS9 
handles windows. I see in the device descriptors a reserved byte for extended address and a 
word reference to A.W#. When Ilook at the VTIO.defs file I see a reference to an address 
that is the MMU address in the GIME chip.

Does OS9 use the same address spaces as the GIME chip internal registers?
 
Is OS9 mapping the GIME chip in and out of the memory map to access the variables in 
RAM?

How does the Column size and Row Size varialble map to the actuall hardware registers? Ie 
like HRES and CRES bits. 

I have a good part of the GIME coded but untested and have most of the the video control 
registers interface to VGA section done. What I am thinking of doing is to set the background 
size as 800x600 with a single color and allow a DECB window to be configurable by the 
current software using the HRES and CRES bits. I can easily add a couple of registers to 
function as postion. This can lead to a whole host of expansion ideas that I have been 
thinking of. I know that some of the limitation of NitrOS9 is the hardware itself. I guess for any 
hardware to expand, an Idea of where the software can go is a first place in starting any 
improvements. 

just some thoughts

james