INT 10H 1123H: Setup ROM 8x8 Font for Graphics Mode

                                                      Compatibility: EGA VGA 
 Expects: AX    1123H
          BL    screen rows code: 00H = user-specified (in DL)
                                  01H = 14 rows
                                  02H = 25 rows
                                  03H = 43 rows
          DL    (when BL=0) custom number of character rows on screen
 Returns: (none)
    Info: Sets up to use the ROM-defined 8x8 characters when the BIOS
          displays text while in graphics modes.  This sets the INT 43H
          vector and sets BIOS variables needed to use the font.

See Also: INT 10H 11H: EGA/VGA Character Generator Functions
          INT 10H: Video Services
          EGA/VGA Data Areas