Re: Page flipping on LFB in protected mode...how??!?!


Tim Roberts wrote:
> spamtrap@xxxxxxxxxx wrote:
> >
> >I am messing around with VESA graphic modes. I started
> >writting my own OS from scratch as a personal project and I took
> >a tangent into graphics. I already implanted Bresenham's line drawing
> >algorithm but I can't for the life of me find enough information about
> >page flipping.
> >
> >I am running my kernel in protected mode. Is anyone on here aware of
> >how I can do page flipping or where I can find the information I need
> >to accomplish this. I would be great if I didn't have to come out of
> >protected mode. Coming back to real mode to flip pages through the BIOS
> >to finally go back to protected mode to then again redo the same thing
> >again ad infinitum is not favorably 'drawing' my attention.
> >
> >I am using VESA mode 118h in linear mode (1024x768x24)
>
> Unfortunately, the frame buffer base address is one of the registers that
> is not standardized from manufacturer to manufacturer. If you really want
> to avoid the video BIOS for this, you will have to do a little bit of
> research to figure out where the register lives for the video cards you are
> interested in.

If I'm using the LINEAR frame buffer, which allows me to access any
part of video memory without having to switch bank, is it possible for
me to change the base address of video mapped memory to any other
memory zone if I were to go through the video BIOS? Or am I limited in
some ways?

Regards
Jean-François Michaud


.

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