Int 10 Fn 18  - Video - Dos/v - Get/set Font Pattern                       [J]

   AH = 18h
   AL = subfunction
       00h get font pattern
       01h set font pattern
   BX = 0000h
   CL = character size in bytes (01h,02h)
   CH = 00h
   DH = character width in pixels
   DL = character height in pixels
   ES:DI -> buffer for/containing font image

Return: AL = status (00h successful, else error)
   ES:DI buffer filled for function 00h if successful

Note:  the supported font sizes are 8x16 single-byte, 8x19 single-byte,
     16x16 double-byte, and 24x24 double-byte

See Also: AH=19h,INT 16/AH=14h