[comp.os.msdos.programmer] Reading VGA memory 320x200x256 need help

cs442a07@cs.iastate.edu (Sunny G) (02/02/91)

Dear Experts:

I have a problem.  Whenever I view anything using CSHOW in the "skip-a-pixel"
modes (simulated 640x480, etc) I find that all the TSR screep capture utilities
I have mess up - its as though they cant find the right size of the screen...

Therefore, I want to write a TSR which will only do one thing:  Save the 320x
200x256 screen, without even checking to see if I am in that mode.  

I know how to write TSRs, barely, but what I dont know is how to read VGA 
memory directly.... I know it begins at 0xa000 segment, but I've also heard of
wierd things like "latches" etc etc.  

Could someone explain to me how I would go about reading the picture out of 
VGA memory?  ALso, how are the bytes stored (planes? no planes? horizontally?
interlaced?) and where (how) do I read the pallette.  

OR, EVEN BETTER:  Could someone show me where I can get a ($free) TSR which 
will work?

Ones that have not worked (off the top of my head): Camera (Deluxe Paint), Grab
(Word Perfect 5.1), about 3-4 shareware ones.

Oh, and if you are wondering about disk writes from my TSR: I wont.  I'll just
write the address of my buffer to a disk file, and then go resident.  I'll have
another program grab the stuff out of the buffer (whose address I read in from
the disk file.)

Thank you, anyone.

Sunjeev "Sunny" Gulati

cs442a07@zippy.cs.iastate.edu
cs442a07@zaphod.cs.iastate.edu
taa65@ccvax.iastate.edu
xdd16@ccvax.iastate.edu

(515) 296-9537

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