Compatibility: EGA VGA
Expects: AX    1120H
ES:BP address of 8x8 font-definition info for > chars 128
Returns: (none)
Info: This just saves ES:BP into the vector for INT 1fH; that is it
defines how the BIOS will display characters from 80H-ffH when in
CGA-graphics mode (200 vertical res).

ES:BP points to a table containing the character-definition codes.  It
should be 2048 bytes long.

See Video Font Definition for byte layout.

Note: This fn requires that you modify BP.  When calling from high-
level languages such as C, be very careful to save and restore
BP, since it is used to keep track of the "stack frame".

- -

INT 10H 1120H: Setup INT 1fH Vector