Switch Video Mode int PMode

AlfaOmega08 · Post by **AlfaOmega08** » Fri Feb 22, 2008 1:43 pm

In Real Mode, we can switch between Video Modes using INT 0x10
In protected mode there is any way to do this or have I to use VMode?

01000101 · Post by **01000101** » Fri Feb 22, 2008 1:47 pm

you have to write the drivers for the video card or standard (vga, svga, etc..).

you might want to consider switching video modes in real-mode then just writing to the buffers in pmode.

xyzzy · Post by **xyzzy** » Fri Feb 22, 2008 2:20 pm

If you want to use VBE, use V8086 mode to perform the mode switch or get card info.

os.hacker64 · Post by **os.hacker64** » Fri Feb 22, 2008 3:51 pm

I believe after reading these posts that I will add switching back to real mode into my kernel so that I can set vesa modes.

EDIT: Is there an interface like VGA for XGA? This sounds weird to me, but you get my point.

Dex · Post by **Dex** » Fri Feb 22, 2008 9:38 pm

I have written a demo to show how to go to realmode from pmode and back, for mode switching (in this case vesa and text mode).
See here: http://www.dex4u.com/demos/VesaDemo.zip
Note: this demo need vesa2.

Also its possible to switch vga modes from pmode, without using BIOS
See here: http://bos.asmhackers.net/docs/vga_without_bios/

AlfaOmega08 · Post by **AlfaOmega08** » Sun Feb 24, 2008 5:26 am

Thanks Dex, I will try with your docs

os.hacker64 · Post by **os.hacker64** » Sun Feb 24, 2008 5:20 pm

os.hacker64 wrote:I believe after reading these posts that I will add switching back to real mode into my kernel so that I can set vesa modes.

EDIT: Is there an interface like VGA for XGA? This sounds weird to me, but you get my point.