Int 21 Fn 47  - Dos 2+ - "cwd" - Get Current Directory                     [D]

   AH = 47h
   DL = drive number (00h = default, 01h = A:, etc)
   DS:SI -> 64-byte buffer for ASCIZ pathname

Return: CF clear if successful
       AX = 0100h (undocumented)
   CF set on error
       AX = error code (0Fh) (see #1366 at AH=59h/BX=0000h)

Notes: the returned path does not include a drive or the initial backslash
   many Microsoft products for Windows rely on AX being 0100h on success
   under the FlashTek X-32 DOS extender, the buffer pointer is in DS:ESI

See Also: AH=19h,AH=3Bh,AH=71h,INT 15/AX=DE25h