This is in favor of bootloader-assisted mode switching. Grub has a
wonderful option we will exploit to set the video mode.
My laptop supports a couple of 32-bit video modes, which is nice,
because I'm not support 24-bit modes.
I'm not sure whether the super-sketchy video memory locator will work
in the real world, but we'll find out sometime soon.
Completely removes:
* The kernel terminal (both VGA and graphical)
* The kernel ANSI parser (obviously)
* kgets() function
* Dozens of other functions that were made useless
Adds:
* Userspace terminal that should work (relatively) well
* Keyboard device driver (implemented with a "pipe" object)
* Stabalized interrupt interface
* `clear` uses the c library
* All panic screens and kprintf() output goes to the serial line ONLY
* The kernel boots directly into /bin/terminal (no arguments, unless you
want to add them (such as -f))
BIOS execution is provided through the `v8086` module, which provides
software emulation of an 8086 processor. It is not currently working
with some BIOSes and may (read: probably will be) replaced with another
emulator (x86emu comes to mind) at some point in the near future. In the
meantime, the default video mode for QEMU works with this and it's
enough to get us on real VESA instead of fake VBE. The `bochs` module
will be renamed in a future commit. Userspace programs have been
adjusted to work at bitrates other than 32 *POORLY*. If you write pixels
left-to-right, they should work fine. They only work with 24-bpp
otherwise, and then you need to be careful of what pixels you are
writing when, or you will overwrite things in other pixels.
You may pass a commandline argument like the following to set display
modes:
vid=vesa,1024,768
Or for stranger modes under QEMU or Bochs, use the bochs VBE
initializer:
vid=bochs,1280,720
Note that the address of the linear framebuffer is still found via
hackish probing instead of PCI or trusting the VBE information, so if
you have things in the wrong memory ranges (0xE0000000+), be prepared to
have them get read.
Once again, this entire commit is a massive hack. I am happy that it
worked, and I will continue to make it less hacky, but in the meantime,
this is what we've got.
Happy holidays.
