=== LMMV ===
* Write mask is directly related to which VRAM is written to.
* FC low then FC high are used to write pixels. The order is not reversed when DIX=1.
e.g. When 8bpp, fc=&1234, DIX=0 and nx=4 then after LMMV has executed we will see the bytes in vram: &34,&12,&34,&12.