From:	oak9755 AT silver DOT sdsmt DOT edu (Olav Kindt)
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: Directly calling bank switch function?
Date:	22 Oct 1996 16:22:00 GMT
Organization:	South Dakota School of Mines and Technology
Lines:	50
Distribution:	world
Message-ID:	<54isb8$4p8@news.sdsmt.edu>
References:	<53j43r$dcq AT oravannahka DOT Helsinki DOT FI> <326B406F DOT 2CD0 AT seitz DOT de>
NNTP-Posting-Host:	silver.sdsmt.edu
To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp

Mirko Geffken (mirko AT seitz DOT de) wrote:
: Joonas W N Reynders wrote:
: > 
: >         If I have a segment:offset (16:16) pointer to a function (this
: > case the bank switch function ptr returned by a VESA GetModeInfo function),
: > how can I call it directly? The bank switch interrup is too slow...
: > 
: >         Thaks in advance,
: > 
: >         Joonas
: > 
: > PS. Email would be nice: I allways forget that I've posted something ;)
: Simply don't use bank switching, as there is something nice as VBE 2.0
: with linear frame buffer.
: 
What if the card doesn't support VBE2.0???

If you want to do bankswitching you can use the
_go32_dpmi_simulate_real_mode_... (Look up the correct spelling)
or __dpmi_simulate.... (Also look up spelling)
You'll find the manuals somewhere at http://www.delorie.com

This is how it would look:

	__dpmi_regs regs;
	regs.x.cs = segment;
	regs.x.ip = offset;
	regs.x.bx = 0;		// Set the page
	regs.x.dx = page;	// The pagenumber
	regs.x.sp = regs.x.ss = 0;	// Don't know why, just do it
	__dpmi__simulate_real_mode_...(&regs);

Well that sould do, hope this helps.

PS: Is there anyway you can access the linear frame buffer when the VBE
version in the VESAINFO is 1.2 ?

I have a videocard that returns this version, but it would be nice if i
could use the linear frame buffer.

Let me know if you know.

Cheers



-- 
Olav Kindt		     | email:	oak9755 AT silver DOT sdsmt DOT edu
737 E. Anamosa Street #103   |		xedb_oak AT debet DOT nhh DOT no
Rapid City SD-57701	     | 		MAIL me man.......

- Raw text -