Question about graphics

ComputerPsi · Post by **ComputerPsi** » Wed Aug 16, 2006 2:34 pm

In svga graphics, one can switch banks of memory in order to use all the memory on a video card. In order to completely write to all of the memory, one needs to know the max amount of memory that can be written without switching banks. (64 kb, 128 kb, etc). Does anybody know how to do that efficently?

Dex · Post by **Dex** » Thu Aug 17, 2006 10:30 am

Do they not default to 64k ?.

ComputerPsi · Post by **ComputerPsi** » Thu Aug 17, 2006 1:18 pm

There are some video cards that don't. I am not certain of how to detect it.

carbonBased · Post by **carbonBased** » Thu Aug 17, 2006 9:21 pm

ComputerPsi wrote:In svga graphics, one can switch banks of memory in order to use all the memory on a video card. In order to completely write to all of the memory, one needs to know the max amount of memory that can be written without switching banks. (64 kb, 128 kb, etc). Does anybody know how to do that efficently?

If you're using VESA APIs, this is included as part of the APIs:

Check out int 0x10, ax == 0x4F01;

es:di points to an application allocated VDE_ModeInfo structure which will contain the number of banks, and their sizes.

--Jeff

OSDev.org

Question about graphics

Question about graphics

Re: Question about graphics