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From: alf@edstip.EDS.COM (John Hamill)
Newsgroups: comp.graphics
Subject: IBM CGA, Using Stack Pushes to Screen Memory.
Message-ID: <313@edstip.EDS.COM>
Date: 14 Jul 89 18:15:55 GMT
Distribution: comp
Organization: EDS - Tech Pubs, Bloomfield Hills, MI
Lines: 17

I am writing a MASM program for the IBM PC CGA monitor.  I am setting the
stack pointer to the screen memory and using PUSHes to move data to this
area of the screen.  This works fine for the whole screen, but when I
do a small rectangle area there is a problem.  The problem is:  I think
the computer is doing an interupt and pushing and poping from the stack,
which is the screen, so now there is garbage on the screen.  This doesn't
happen when I do the whole screen becouse I write over the whole screen and
this writes over the garbage.  Is there a way to make the computer not do
any interupts while I'm doing this screen push?  Any other comments would
be helpful.  I am doing this form of screen update becouse it is very very
fast, and I don't want to see the screen being painted, I want the screen
to snap to a new image.
-- 
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