From:	Shawn Hargreaves <Shawn AT talula DOT demon DOT co DOT uk>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: VESA 1.2
Date:	Mon, 30 Jun 1997 17:48:17 +0100
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Distribution:	world
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References:	<33B7C265 DOT 7794 AT wanadoo DOT fr>
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To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp

Alan & Vivien Poppleton writes:
>I am using 640*480*256 VESA 1.2 graphics mode.  Is there a 
>faster method of switching banks rather than thtough the BIOS?

No.

>       I know in real-mode there is a pointer to the video card 
>provided in the vesa_modeinfo structure that works on VESA 1.2.  And in 
>protected mode there is also a pointer but only for VESA 2.0!  Is 
>ther a protected mode function for VESA 1.2 as well, 

VESA 1.2 is purely a real mode API. That's why VBE 2.0 is such a nice
thing!

>or is it possible to call the real-mode address from protected mode? If 
>so how?

You could use DPMI function 0x0301 (via the libc routine 
__dpmi_simulate_real_mode_procedure_retf()), but there's no great
advantage in using that over calling the real mode interrupt: both
methods require the expensive mode switch. For fast graphics, VBE 2.0 is
the way to go...


--
Shawn Hargreaves - shawn AT talula DOT demon DOT co DOT uk - http://www.talula.demon.co.uk/
Beauty is a French phonetic corruption of a short cloth neck ornament.

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