OSDev.org

Hello,
I am coding a graphic driver for my OS, but I have no idea how to start.
My question is: Do you know any papers on this subject ?
I am looking for how passing in VESA mod without using BIOS interruptions.

VESA itself is a BIOS-only specification.

Setting resolutions beyond 320x200 in 256 Colors or 640x480 in 16 Colors is graphics card-dependant! The VESA BIOS only handles those for you!

Ok, thank you for your answer.
So the best and easier mean to acces to a graphic mode, is to switch mode with the interruptions of the BIOS before going in pmode.

For vesa, you can set vesa up in realmode before go to pmode, this is the simplest way, but you are stuck in that mode.
To change mode from pmode you can set up v86, or swich from pmode to real mode change vesa mode and swich back.
With vesa 3 you can do it from pmode using 16bit pmode (i have not head of any one, who has got this to work)

I have made a demo (Asm with full code )that set vesa2 up, go's to pmode does a 10 second vesa demo, swich's to realmode change's to text mode, goes back to pmode does a 10 second pmode text demo and keep do this until you reboot.

Let me know if you want a copy.

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ASHLEY4.

He Ashley4,

that sounds good. I'm curious how you do it (I'm planning vesa mode GUI after I get my floppy to work)

Can you send a copy to: m.lont (at) student.tue.nl

Thanx in advance,

Lont

If you go here:   http://board.flatassembler.net/viewtopic.php?t=1940
and go to the 4th message by me (ASHLEY4), and download the zip called "VesaDemo.zip" , It has a program the puts the demo on a floppy disk, it come's with full fasm code.
To use the demo you need a vesa2 card, and the program to put it on the disk need's windows.
When you have finished with the demo, you can use the disk to test your own OS or bootable program, by deleting the file called kernel32.exe, renaming your program "kernel32.exe and putting it on the disk and rebooting.

Note: Do not use dos int's in your OS, and assemble as a mz exe (bios are ok).

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ASHLEY4.

I have had the vbe pmode interface working on two seperate cards.
The document that tells you how to do it is VBE3 from vesa.

There are a couple of things that you need to change

1.   Some cards have bios > 32k and you need to allow for this when seting up the code and data segments.

       - nvidia 440mx  64k bios
       - ATI 9660      128k bios

2.   Also you need to setup a callgate (16bitpmode) so that you can do a 32bit  return as the 16bit return in the bios will fail.

Keep Posting if you have any trouble

pkd

He ASHLEY4,

Thanks for the code, I will have a look when I have the time.

MZZLS,

Lont