From:	Shawn Hargreaves <Shawn AT talula DOT demon DOT co DOT uk>
Newsgroups:	rec.games.programmer,comp.os.msdos.djgpp
Subject:	Re: VBE Mode List
Date:	Thu, 26 Mar 1998 19:20:55 +0000
Organization:	None
Message-ID:	<5PO9HMAXqqG1Ew7T@talula.demon.co.uk>
References:	<01bd582f$3875e6c0$LocalHost AT ctx>
NNTP-Posting-Host:	talula.demon.co.uk
MIME-Version:	1.0
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To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp

Adrian Francis writes:
>I have created a VBE interface in DJGPP but I am having problems with the 
>VideoModePtr, which is a pointer to a list of available video modes.
>
>I have read the VBE2.0 specification and it does not seem to state what sort of 
>pointer this is.  I have presumed that it is a real-mode far pointer but no 
>matter what I try I cannot get access to the list.

Yes, it is a real mode seg:offset pair. You need to split it up into two
parts, convert to a linear address (using the formula seg*16 + offset),
and then use the dosmemget() or _farpeekw() functions to retrieve the
contents of the list.

>Can anyone help?  A code snippet would be useful!

Look at the find_vesa_mode() function from the Allegro vesa.c file.


--
Shawn Hargreaves - shawn AT talula DOT demon DOT co DOT uk - http://www.talula.demon.co.uk/
"Pigs use it for a tambourine" - Frank Zappa

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