Int 21 Fn 6300  - Far East DOS 3.2+ - Get Double Byte Character Set Lead-  [D]

   AX = 6300h

Return: AL = error code
       00h successful
       DS:SI -> DBCS table (see below)
       all other registers except CS:IP and SS:SP destroyed
       FFh not supported

Notes: probably identical to AH=63h/AL=00h for DOS 2.25
   the US version of MS-DOS 3.30 treats this as an unused function,
     setting AL=00h and returning immediately
   the US version of DOS 4.0+ accepts this function, but returns an empty
     list

See Also: AX=6300h"DOS 2.25"

Format of DBCS table:
Offset Size    Description
 00h  2 BYTEs  low/high ends of a range of leading byte of double-byte chars
 02h  2 BYTEs  low/high ends of a range of leading byte of double-byte chars
   ...
  N   2 BYTEs  00h,00h end flag