Path: utzoo!utgpu!water!watmath!watdcsu!magore
From: magore@watdcsu.waterloo.edu (Mike Gore, Institute Computer Research - ICR)
Newsgroups: comp.sys.atari.st
Subject: Re: ST hardware scrolling
Message-ID: <4650@watdcsu.waterloo.edu>
Date: 27 Apr 88 17:49:27 GMT
References: <544@csvax.liv.ac.uk> <4484@batcomputer.tn.cornell.edu>
Reply-To: magore@watdcsu.waterloo.edu (Mike Gore, Institute Computer Research - ICR)
Organization: U. of Waterloo, Ontario
Lines: 18


My 2 cents to do 'hardware' scrolling would be to do it partly
in software and hardware. If we were to use the horizontal interrupt
we could maintain a linked list of scan lines - or even a group of
scan lines. This could be run as a interrupt driven display process that
would then be a set up as a display list of sorts.  In order to scroll the 
entry link for the beginning of the display would only need to be changed. If 
a group of scan lines were used to make up a single character line interrupt 
Overhead could be reduced and character I/O would be slightly easier. The 
disadvantage to this method would be the waisted space at the end of each line 
[ required to fall on 256 byte offsets ] and interrupt overhead.

	Comments ???

 
# Mike Gore 
# Institute for Computer Research. ( watmath!mgvax!root - at home )
# These ideas/concepts do not imply views held by the University of Waterloo.