From:	Endlisnis <s257m AT unb DOT ca>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: VESA: hints, clue but no examples
Date:	Tue, 18 Aug 1998 11:17:22 -0300
Organization:	NBTel Internet
Lines:	26
Message-ID:	<35D98CF1.F906723E@unb.ca>
References:	<1998081519323200 DOT PAA25189 AT ladder01 DOT news DOT aol DOT com> <35D66C0C DOT 8D8F94C8 AT geocities DOT com> <35D70CC1 DOT BCA4F4EF AT unb DOT ca> <35D93933 DOT 40CF1D5 AT geocities DOT com>
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To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp

Merlin wrote:

> >     To get the 256-byte buffer, you need to use the Transfer Buffer, this is very
> > well documented in the FAQ. (Section #18.2 How to use buffers with DOS/BIOS
> > services).
> ahh..ok thanks...i'll take a look at that...
> do all vesa 1.2 modes use bank switching?
>       Merlin.

    Not nessecarily, but yes.  There do exist VESA 1.2 modes, usually card specific ones
that don't need bank-switching.  My ATI card supports VESA 320x200x256 where bank
switching isn't nessecary unless you want to do hardware scrolling.  Some SVGA cards
(Tridents) also support SVGA Text modes which don't require bank switching, but for all
intensive purposes, you should expect all VESA 1.2 modes to requires bank-switching.  To
make things even worse, if you are in a 24-bit mode, a bank can switch in the middle of
the 24-bits.

--
     (\/) Endlisnis (\/)
          s257m AT unb DOT ca
          Endlisnis AT GeoCities DOT com
          Endlis AT nbnet DOT nb DOT ca

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