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From: mdavis@pro-sol.cts.com (Morgan Davis)
Newsgroups: comp.sys.apple2
Subject: Re: updating windows fast
Message-ID: <7566@crash.cts.com>
Date: 15 Feb 91 09:36:07 GMT
Sender: root@crash.cts.com
Lines: 12

In-Reply-To: message from acmfiu@serss0.fiu.edu

The fastest way to scroll a window is to calculate the actual video RAM
locations for its content, and then use a fast 65816 routine to do the
pixel shifting on your own, preferably by using a table of offsets, or even
faster, by generating code at runtime that moves pixels in an unrolled loop
of load-store instructions.  Takes up a bit of RAM, but can result in
blindingly fast scrolls, albeit against the rules.

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