vgabios: Framebuffer fixes for CGA and planar graphics modes.

Fix missing divide by 2 in CGA mode scroll.  Consistently use
cheight/2 for all uses.

Planar graphics character write has a read to video memory with a side
effect - mark that as volatile so the compiler doesn't optimize it
away.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
1 file changed
tree: 41889ca152166985f32c6d25fee1ee8b4a5cb574
  1. .gitignore
  2. COPYING
  3. COPYING.LESSER
  4. Makefile
  5. README
  6. TODO
  7. src/
  8. tools/
  9. vgasrc/