I had to change PhysicalPage around a bit for this. Physical pages can now
be instantiated for any arbitrary physical address without worrying that
such pages end up in the kernel page allocator when released.
Most of the pieces were already in place, I just glued everything together.
This is a monster patch that required changing a whole bunch of things.
There are performance and stability issues all over the place, but it works.
Pretty cool, I have to admit :^)
Use the BochsVGA card's virtual-height + virtual-y features to implement
a "hardware double buffering" type scheme.
This is a performance degradation since we now draw a bunch more than before.
But there's also no tearing or cursor flickering. I'm gonna commit this and
try to improve upon it. :^)
Instead of cowboy-calling the VESA BIOS in the bootloader, find the emulator
VGA adapter by scanning the PCI bus. Then set up the desired video mode by
sending device commands.
The system can finally idle without burning CPU. :^)
There are some issues with scheduling making the mouse cursor sloppy
and unresponsive that need to be dealt with.
