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What are the Video Card's Ports and How do I use them.
Posted: Thu Dec 16, 2010 1:48 pm
by ThatGuy22
My goal of this is to switch the Graphics Card's Video memory pointer and to change the resolution of the screen while only using ports and not DOS interrupts.
Re: What are the Video Card's Ports and How do I use them.
Posted: Thu Dec 16, 2010 2:16 pm
by Combuster
VGA Hardware. That doesn't get you sane resolutions beyond 640x480 though
But even the regular bios interrupts don't come from DOS so you can use them anywhere from real mode
Re: What are the Video Card's Ports and How do I use them.
Posted: Fri Dec 17, 2010 3:29 am
by Chandra
Combuster wrote:VGA Hardware. That doesn't get you sane resolutions beyond 640x480 though
True. To implement high resolution using ports, you need to write custom drivers for each graphics card. But this is truely a nightmare as much of the graphics card available are not well documented. So far I have been able to find some documents regarding ATI, S3 and few others (that too for limited cards only) so if you find something new, I too would be interested.