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From: mp1u+@andrew.cmu.edu (Michael Portuesi)
Newsgroups: comp.sys.amiga
Subject: Re: Amiga serial questions
Message-ID: 
Date: Mon, 7-Dec-87 01:30:00 EST
Article-I.D.: andrew.MViYfcy00W0Wy3g0xY
Posted: Mon Dec  7 01:30:00 1987
Date-Received: Sat, 12-Dec-87 07:09:32 EST
Organization: Carnegie Mellon University
Lines: 33
In-Reply-To: <8712050831.AA11465@cory.Berkeley.EDU>



 dillon@CORY.BERKELEY.EDU (Matt Dillon) writes;

> The Amiga can
> read data at that speed, but not scroll at that speed.

[speed = 19.2Kb]

Sure it can.  If you set up a circular buffer in memory and set up a copper 
list to point the hardware at each display line, performing a scroll operation 
is as easy as updating a few pointers and clearing a line's worth of memory.  
Of course, this has to be on a custom screen, and you can forget about using 
any of the system software to do your text rendering and/or your interface 
stuff, but it *is* possible.  I thought about writing such an emulator on the 
Atari 800, which also has the display hardware to pull off such "tricks," but 
doesn't have a large complement of system software whose functionality would 
have to be duplicated for the project.

The folks writing software for the Amiga haven't even begun to investigate the 
kinds of things you can do with "dirty tricks."  (which is probably good, 
since it probably wouldn't stand a chance of running on a future Amiga).  The 
ST people are; witness the recent paint program the ST community has been 
raving about which displays all 512 colors on the screen with a tight 68000 
loop.

				--M


Michael Portuesi / Carnegie Mellon University
ARPA/UUCP: mp1u+@andrew.cmu.edu		BITNET: rainwalker@drycas

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