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Article #2379Re: ST bus cycles...BLITTER?!?!?!?!?!?!?
From: Jan Gray
Date: Wed, 05 Feb 1986 15:45
Date: Wed, 05 Feb 1986 15:45
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In article <12180482042.28.G.DYER@SU-SCORE.ARPA> G.DYER@SU-SCORE.ARPA (Landon Dyer) writes:
>
>There are two 250ns windows. One window is for "static" system requests
>(video DMA and memory refresh). The other window is available for disk
>DMA, blitter DMA, and processor accesses. Refresh cycles are done during
^^^^^^^^^^^
>horizontal and vertical blank (and take, say, 5% of the first window).
>When the first window is not being used, it is available to fill requests
>that would otherwise go to the second window.
WHAT BLITTER????? Somewhere in the documentation I saw an interrupt
vector for "gpu blt done"...but nothing else! I can't believe there
is special hardware for bitblt on the ST, since vro_cpyfm() is
too damn slow(*). Unless, of course, the "blitter" is only useful for
doing no-skew, whole word transfers...
Please please please tell us more. Maybe you could even fill us in on
how to do bitblt from the line A vector (since my documentation (and
others) were missing the last n pages of the "Long Awaited Line A
Document").
Thanks,
Jan Gray Looking Glass Software, Waterloo Ont. (519) 884-7473
p.s. Are you *the* l. dyer who wrote the BIOS, etc (or at least had his
name on the listings?)
(*) That is, for doing large image processing tasks like "spreading" the
screen, running life on the whole screen etc. (BTW, can anyone beat
400,000 life cell-generations per second on their ST?)
Technical Details
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Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/18/84; site looking.UUCP Path: arc1-ca.pugleaf.net!utzoo!watmath!looking!jan From: jan@looking.UUCP (Jan Gray) Newsgroups: net.micro.atari Subject: Re: ST bus cycles...BLITTER?!?!?!?!?!?!? Message-ID: <493@looking.UUCP> Date: Wed, 5-Feb-86 10:45:18 EST Article-I.D.: looking.493 Posted: Wed Feb 5 10:45:18 1986 Date-Received: Thu, 6-Feb-86 04:46:30 EST References: <12180482042.28.G.DYER@SU-SCORE.ARPA> Reply-To: @looking.UUCP (Jan Gray) Organization: Looking Glass Software Ltd. Waterloo, Ontario Lines: 30