How to reset VGA? & Re: EGA/VGA ReadPixel function in C

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#2194

From: michael k finegan
Date: Wed, 19 Sep 1990 22:09

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hpasanen@niksula.hut.fi (Harri Pasanen) writes:

>Sorry for this simple question:

>Could somebody direct me to a EGA/VGA ReadPixel() function written in C.
>The catch is that it should go directly to video RAM bypassing the EGA/VGA
>bios.  

>Thank's	

>Harri Pasanen

Richard Wilton's "Programmer's Guide To PC & PS/2 VIDEO SYSTEMS" (Microsoft
Press) has just that (starting on page 125 ...).

--

Now - I have a question for the net. Resetting all VGA registers to their
default (or previous) values != calling int 10h to set video mode. What is
different ? I have an application where calling int 10h after various
direct programming operations on the VGA restores the video, but saving all
registers, performing operations, and restoring all registers does not. Why ?
I have tried resetting the sequencer, and hardware, with sequencer register's
reset register and crt controller register's mode control register. No luck.
What does the Bios do that I don't know about ?

						- Mike
						  mfinegan@uceng.uc.edu

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Path: arc1-ca.pugleaf.net!utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!wuarchive!zaphod.mps.ohio-state.edu!sol.ctr.columbia.edu!cica!iuvax!uceng!mfinegan
From: mfinegan@uceng.UC.EDU (michael k finegan)
Newsgroups: comp.os.msdos.programmer
Subject: How to reset VGA? & Re: EGA/VGA ReadPixel function in C
Message-ID: <6154@uceng.UC.EDU>
Date: 19 Sep 90 22:09:38 GMT
References: <HPASANEN.90Sep6195334@silver-surfer.hut.fi>
Distribution: comp.os.msdos.programmer
Organization: Univ. of Cincinnati, College of Engg.
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