VBE in Protected Mode Tutorial?

[OniLink10]

Hey guys, I'm new here. Does anyone know a simple way to activate VBE Mode 0x112 in Protected Mode Assembly? Here is my current .text section for my Kernel loaded by GRUB:

Code: Select all

;;;;;;;;
; Text ;
;;;;;;;;
section .text
align 4

MultiBootHeader:
	dd MAGIC
	dd FLAGS
	dd CHECKSUM

STACKSIZE equ 0x4000

loader:
	mov esp,stack+STACKSIZE
	push eax
	push ebx
	call kmain
	cli
hang:
	hlt
	jmp hang

Also, how do I find out where VRAM starts in that mode? A Final Question, VBE is supported on all Built-In/PCI/AGP/PCI-E Video Cards, right? I'm confused. D:

EDIT: Oops, I think this is the wrong board. D:

[JackScott]

Moved.

[Troy Martin]

Welcome!

We have a great wiki, I suggest you check it out, especially the Getting VBE Mode Info page which helps you get a VBE mode. VBE mode numbers are no longer standardized as of, I think, VBE 2.0.

Have fun,
--Troy

[Combuster]

This is a good time to add a FAQ entry on mode changes in general...

[Troy Martin]

We have VGA mode setting-ness in the FAQ, but we need VBE. (it will be done in three minutes)

[gedd]

This is a good time to add a FAQ entry on mode changes in general...

If you are not in VBE 3.0, unless you have not a V86 mode manager you cannot change VESA mode in PM if you have not VBE version on you graphics card
- Bochs, virtual PC, vmWare, virtualbox are all in VBE 2.0
- having a V86 mode manager is a lot of work

[Combuster]

We have VGA mode setting-ness in the FAQ, but we need VBE. (it will be done in three minutes)

Already there. Infact, I plan on deleting the VGA entry to make the new one more obvious (it covers both VGA and VBE).

Unless you have not a V86 mode manager you cannot change VESA mode in PM

That's not true. Read the FAQ entry to see why.

[gedd]

Unless you have not a V86 mode manager you cannot change VESA mode in PM

That's not true. Read the FAQ entry to see why.

How to ? Return in real mode ? Great difference ..., This solution is worse.

[kmtdk]

well

first
if you got VBE 3.0 you can use Pmode
secound:
combuster is one of the best here at graphic's.

[Combuster]

the Protected Mode entry point would be the fourth option. I have not listed it in the FAQ since it's practically nowhere supported.

I do find it sad that gedd is putting up this reply and obviously did not read the FAQ entry in question.

[Dex]

well

first
if you got VBE 3.0 you can use Pmode

This is a 16bit pmode, that is not much differant to going back to realmode as you still need to switch back, but just not as far.

@All, Please try something before you knock it, the best and easist way to switch graphic modes is to goto and from realmode, its simple and works.
Put your heads in the sand if you want and do not give people a chose to switch modes.
But do not knock it, just because one person says it so, so it must be true, following like a bunch of sheep.

Pmode vesa mode switching demo available here: http://www.dex4u.com/demos/VesaDemo.zip

And remember the world is not flat.

[Combuster]

Let me rephrase that: "People should not be telling you what is right and wrong. However I am telling you that dropping to real mode is the only acceptable option"

[JamesM]

well

first
if you got VBE 3.0 you can use Pmode

This is a 16bit pmode, that is not much differant to going back to realmode as you still need to switch back, but just not as far.

@All, Please try something before you knock it, the best and easist way to switch graphic modes is to goto and from realmode, its simple and works.
Put your heads in the sand if you want and do not give people a chose to switch modes.
But do not knock it, just because one person says it so, so it must be true, following like a bunch of sheep.

Pmode vesa mode switching demo available here: http://www.dex4u.com/demos/VesaDemo.zip

And remember the world is not flat.

Please understand that not everyone uses 16-bit real mode assembly. Most here write multitasking operating systems with some kind of soft time deadlines (i.e. something can't take so long that the user notices a response lag). Moving to realmode means you have to disable interrupts during the process, and you lose paging and thus access to the majority of your kernel's runtime data.

There are multiple methods for a reason. If you expect people to keep an open mind, please extend the same courtesy to yourself.

And remember, the world may not be flat, but neither is the world still living in the caveman era.

James

[Dex]

And remember, the world may not be flat, but neither is the world still living in the caveman era.
James

But you are ( as in all OS Dev's ) in the caveman era, but you try to pretend your not, you have basic graphics, basic drivers, basic apps.
Thats what a hobby desktop OS is, its a caveman OS, just get real.

[gedd]

well

first
if you got VBE 3.0 you can use Pmode
secound:
combuster is one of the best here at graphic's.

Yes you can in VBE 3, that's what i was saying but my post was not clear.
You can chnage mode but "get " functions are not operationnal (so you have to call them before going in PMode)
Unfortunaly as i said none of the virtual machine got VBE 3 card
You can have also a PM interface in VBE 2 but only for 3 functions i believe to manage window ,granularity (if no LFB) and color
So in this case you haveto change mode before going to PM, and keep it unless ...

And at last it was not a personnal attack for combuster so dont be sad !!
I have read the FAQ and VESA standard too !