INT 21 - DOS 2.25 only - GET LEAD BYTE TABLE ADDRESS
AX = 6300h
Return: CF clear if successful
DS:SI -> lead byte table (see below)
CF set on error
AX = error code (01h) (see AH=59h)
Notes:  does not preserve any registers other than SS:SP
the US version of MSDOS 3.30 treats this as an unused function,
setting AL=00h and returning immediately
SeeAlso: AH=07h,AH=08h,AH=0Bh

Format of lead byte table entry:
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

See also: 216301

216300 - DOS 2.25 only - GET LEAD BYTE TABLE ADDRESS