INT 2F CU - NLSFUNC.COM - CHANGE CODE PAGE
        AX = 1401h
        DS:SI -> internal code page structure (see below)
        BX = new code page (see INT 21/AX=6602h)
        DX = country code???
Return: AL = status
             00h successful
             else DOS error code
Note:   this function is called by the DOS v3.3+ kernel
SeeAlso: AX=1400h"NLSFUNC",AX=1402h"NLSFUNC",INT 21/AH=66h

Format of DOS 3.30 internal code page structure:
Offset  Size    Description
 00h  8 BYTEs   ???
 08h 64 BYTEs   name of country information file
 48h    WORD    system code page
 4Ah    WORD    number of supported subfunctions
 4Ch  5 BYTEs   data to return for INT 21/AX=6502h
 51h  5 BYTEs   data to return for INT 21/AX=6504h
 56h  5 BYTEs   data to return for INT 21/AX=6505h
 5Bh  5 BYTEs   data to return for INT 21/AX=6506h
 60h 41 BYTEs   data to return for INT 21/AX=6501h

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