[comp.sys.ibm.pc] Difficult EGA Question

toma@tekgvs.TEK.COM (Tom Almy) (08/10/87)

I have written a small (4k) Terminate-and-Stay-Resident routine that
makes color screen copies of the EGA display to a Tektronix color printer.
To detect changes in the color palatte, I take over INT 10, and watch for
functions 0B and 10.  This works fine for all programs except for those
which insist on setting the palatte registers directly (BOO! HISS!) such
as PC-PAINT.

Now the IBM Tech Ref says that the registers are write only, yet there must
be some way to read these registers since I have a copy of a large TSR,
Pizazz!, which does it.

Do any Net readers know how?  Just reading from the write-only port does
not work.  A cursory look into Pizazz revealed nothing (it is about 90k).
It also detects changes in the 4 color palattes.

Thanks in advance to anyone who knows the answer and replies.

Tom Almy
...tektronix!tekgvs!toma
toma@tekgvs.TEK.COM