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From: dyer@atari.UUCP
Newsgroups: comp.sys.atari.st
Subject: Re: Vertical Blank Interrupts
Message-ID: <660@atari.UUCP>
Date: Sat, 14-Mar-87 11:33:44 EST
Article-I.D.: atari.660
Posted: Sat Mar 14 11:33:44 1987
Date-Received: Sun, 15-Mar-87 14:04:21 EST
References: <741@eneevax.UUCP>
Organization: Atari Corp., Sunnyvale CA
Lines: 20

In article <741@eneevax.UUCP>, iarocci@eneevax.UUCP (John Iarocci) writes:
> Then, at some point, the system randomly
> writes its own vector right on top of mine.  Great!
> 
> Well, I set the program to start checking for an empty slot with the second
> entry in the vbi queue next.  Now, my handler survives the boot process.  Un-
> fortunately, now I can no longer run Degas Elite!

The first vblqueue slot is reserved for the VDI, and the
documentation says so.  If an application is hard-coded to use
(say) the 2nd slot, it is doing things wrong, wrong, wrong.

You can always intercept the interrupt itself.  You will have to
do your own mutual exclusion (trivial).

-- 
-Landon Dyer, Atari Corp.	    {sun,lll-lcc,imagen}!atari!dyer

The views expressed here do not not		
necessarily reflect those of Atari Corp.	Segments are for worms.