Int 18  - Nec Pc-9800 Series - Video                                       [J]

   AH = function
       0Ah set video mode
       0Bh get video mode
       0Ch start text screen display
       0Dh end text screen display
       0Eh set single display area
       0Fh set multiple display area
       10h set cursor shape
       11h display cursor
       12h terminate cursor
       13h set cursor position
       14h read font patter
       16h initialize text video RAM
       1Ah define user character
       others
   ???

Return: ???

Notes: details are not available at this time
   text video RAM is located at segments A000h (characters) and A200h
     (attributes), graphics video RAM at segment C000h

Bitfields for NEC PC-9800 series video attributes:
Bit(s) Description (Table 0572)
 0 disable drawing character
 1 blinking
 2 reverse video
 3 underline
 4 vertical line
 7-5   color
   (0=black, 1=blue, 2=red, 3=purple, 4=green, 5=cyan, 6=yellow, 7=white)