From: rossi AT cs DOT unibo DOT it (Davide Rossi)
Newsgroups: comp.os.msdos.djgpp
Subject: Re: VESA Bank Switching...Please Help Me!
Date: 24 Mar 1998 05:12:17 GMT
Organization: Department of Computer Science, University of Bologna, Italy
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References: <3511DA80 DOT A17208CE AT gold DOT com DOT br>
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Sérgio Vale e Pace (space AT gold DOT com DOT br) wrote:


: > I am working with VESA 1.2 and I have got the 32-bit address of the
: > bank-switching function...but can I call it without crashing? No.
: >

: Well, you have two options, the easy one it's use the VESA bios function
: (0x4f05), but you are probably saying "Oh NO! again somebody telling me to
: use the function 5", and you have the hard way, you can use the DPMI
: function to call real mode procedure, to be precise
: "__dpmi_simulate_real_mode_procedure_retf", and call the function using this
: (use the on-line manuals for more information about how exactly do this, but
: it is not really dificult).

: The bios method is really easier to use in real code, but in a test in the
: "i'm not sure if this will work" style I find the direct method a little bit
: faster. If you want to make more perfermonce tests about this I will be glad
: if you let me know your results.

I tried that a lot of time ago and I noticed no relevant speed difference.
You need to raise an interrupt anyway when using
__dpmi_simulate_real_mode_procedure_retf...

CIao,
	Davide.