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From: ose21@wn3.sci.kun.nl (Rene Schreurs)
Newsgroups: comp.graphics
Subject: SPEED UP EGA-MEMORY WRITE
Keywords: EGA write graphics
Message-ID: <2474@wn1.sci.kun.nl>
Date: 22 Nov 90 11:46:15 GMT
Sender: root@sci.kun.nl
Reply-To: ose21@wn3.sci.kun.nl (Rene Schreurs)
Distribution: comp
Lines: 31

Hi there!

I have a little trouble with a program i'm writing.
I want to make a scroll in which a text is displayed and just using
panning doesn't seem right to me, because i don't know yet how large
the text is going to be (perhaps 2000 tokens or more, if i have enough
inspirition).
I want to use EGA-mode 10h (640*350*16) and put some nice graphics on
top of the scroll.
Furthermore i want the program to be able to run on a 4,7MHz pc,
(do they still exist?????).
The problem is that if i want to make a NICE scroll, i'll have to write
about 2000 bytes to the EGA-memory in one vertical retrace, but i just
don't succeed to write more than about 500 bytes!
So my question is, how to write faster to the EGA-memory.
I have been fooling around with the clocking mode register, because i read
in Bradley Dyck Kliewer (EGA/VGA a programmer's reference guide) something
about disabling the display and in that way assigning all memory acces
time to the CPU (which would make it possible to write about 2500 bytes in
1 vertical retrace), but this doesn't work.
Does anybody know why this doesn't work, or how i CAN write more bytes
to the EGA-memory?
Any suggestion would be appreciated!

                                            Rene Schreurs
                                            University of Nijmegen
                                            The Netherlands
                                            email: ose21@wn3.sci.kun.nl
 

                         Have a nice debug!