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Article #1586Re: Modified Display Lists
From: Courtney Goeltzenleuchter
Date: Tue, 26 Nov 1985 05:37
Date: Tue, 26 Nov 1985 05:37
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Hi, you've probably already got a dozen answers on this one, but since I know the answer I thought I'd throw in my two cents worth. The Atari OS stores the location of the display list in locations 560, 561 (decimal usual low, high format). Every 60th of a second a vertical blank interupt is generated and this 'shadow' value is put into 54274, 54275 which tells the hardware to really find the display list. So, in effect, it makes the last instruction almost useless, the only thing it does is tell the hardware to stop sending stuff to the screen. In other words if you want to change whereyour display list is located you'll have to chage the 'shadow' memory. If you want to know ALL about the Atari 800 and related computers your best bet is the book "De Re Atari" it's just packed with useful info. Well I hope this answered you question. Have fun. -Courtney Goeltzenleuchter -- c160-1bj@holden@BERKENLEY.EDU
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Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.3 4.3bsd-beta 6/6/85; site ucbvax.BERKELEY.EDU Path: arc1-ca.pugleaf.net!utzoo!watmath!clyde!burl!ulysses!ucbvax!info-atari From: c160-1bj%holden@UCBVAX (Courtney Goeltzenleuchter) Newsgroups: net.micro.atari Subject: Re: Modified Display Lists Message-ID: <8511260537.AA22287@ucbholden> Date: Tue, 26-Nov-85 00:37:28 EST Article-I.D.: ucbholde.8511260537.AA22287 Posted: Tue Nov 26 00:37:28 1985 Date-Received: Wed, 27-Nov-85 06:18:07 EST References: <8511252100.AA22014@ucbvax.berkeley.edu> Sender: daemon@ucbvax.BERKELEY.EDU Organization: University of California, Berkeley Lines: 14