Re: Detecting VGA retrace! HELP!

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#608

From: Dave Kirsch
Date: Wed, 08 Apr 1992 02:19

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In article <1992Apr8.105623.7301@waikato.ac.nz>, singlis@waikato.ac.nz writes:
> Can anyone tell me which interrupt/mem location I can check to see if the
> raster is in a retrace, this is so I can perform "nice" palette adjustments
> without a lot of flicker...

If you're using C, this handy macro will do it for you:

#define vblstat()       (inp(0x3DA)&8)   /* use for MCGA/VGA only! */

And a simple 'if (vblstat())' will work in your code.

Basically, you have to read the MCGA/VGA port 0x3da and see if bit 3 is set.

/// Dave.
--
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/// Dave 'Zoid' Kirsch         | Vancouver, BC |Internet:
MIND LINK! Communications Corp.|   CANADA      |  zoid@mindlink.bc.ca
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Life is a wonderfully strange game.   The coincidental and the planned all
merging together into this mass of events which bewilders us.  It can only
get better.

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Path: arc1-ca.pugleaf.net!sparky!uunet!spool.mu.edu!agate!rsoft!mindlink!a563
From: Zoid@mindlink.bc.ca (Dave Kirsch)
Newsgroups: comp.os.msdos.programmer
Subject: Re: Detecting VGA retrace! HELP!
Message-ID: <11308@mindlink.bc.ca>
Date: 8 Apr 92 02:19:45 GMT
Article-I.D.: mindlink.11308
Organization: MIND LINK! - British Columbia, Canada
Lines: 22