A faster alternative to (Microsoft's) _remapallpalette.

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#4879

From: H Bruce
Date: Mon, 25 Feb 1991 14:46

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I am using the 320 X 200 X 256 colour graphics mode to display greyscale images.
This involves setting up each of the 256 entries in the palette with 
a grey scale. Using the _remapallpalette function this takes several seconds for
what must be a trivial task. I guess the BIOS is getting in the way.
Assuming I have a "register compatible" VGA card (which almost all of them are)
I should be able to write directly to the VGA chip.
Does anyone know the relevant port addresses for programming the VGA palette ?

Thanks,

Henry Bruce.

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Path: arc1-ca.pugleaf.net!utzoo!utgpu!news-server.csri.toronto.edu!bonnie.concordia.ca!ccu.umanitoba.ca!herald.usask.ca!alberta!ubc-cs!uw-beaver!mit-eddie!wuarchive!zaphod.mps.ohio-state.edu!samsung!spool.mu.edu!uunet!mcsun!ukc!edcastle!elee24
From: elee24@castle.ed.ac.uk (H Bruce)
Newsgroups: comp.os.msdos.programmer
Subject: A faster alternative to (Microsoft's) _remapallpalette.
Message-ID: <8705@castle.ed.ac.uk>
Date: 25 Feb 91 14:46:55 GMT
Distribution: comp
Organization: Dept. Electrical Engineering, Edinburgh University, Scotland, UK.
Lines: 11