[comp.sys.hp] How does one directly access display memory on the HP 110?

nyenhuis@pur-ee.UUCP (John Nyenhuis) (02/07/90)

Hi,

   I am nearly done porting Kermit 3.0 to the HP 110 and 
Portable Plus computers. One new feature is Tektronix
graphics terminal emulation. As part of this, I am 
saving the display memory when the user toggles between
the graphics and alpha displays. I think I have this 
figured out on the Plus. The alpha display begins at 
8000:0000, each line is 160 bytes long, and successive
lines are offset by 256 bytes. Doing an "in al,83h" gives
the offset in lines from 8000:0000 of the top line of the
display. However, using this on the 110 always results in 
the first page of display memory getting stored.

So the question is: How can one directly access the 
alpha display memory on the HP 110?  (I didn't find 
anything on this in the Programmers Tools.)

Thanks,

   John

P.S.
Please advise if you would be interested in testing Kermit
3.0 for the 110 and Portable Plus.


John Nyenhuis   Purdue University  School of Electrical Engineering
West Lafayette IN 47907   (317)494-3524     nyenhuis@ee.ecn.purdue.edu