INT 21 - DOS 2+ - "CWD" - GET CURRENT DIRECTORY
	AH = 47h
	DL = drive number (00h = default, 01h = A:, etc)
	DS:SI -> 64-byte buffer for ASCIZA NUL-terminated ASCII string.	The ASCIZ string "ABC" consists of the four bytes 41h, 42h, 43h, and 00h.  Unless otherwise specified, maximum lengths given in the interrupt list do not include the terminating NUL. pathname
Return: CF clear if successful
	    AX = 0100h (undocumentedInformation about a product which is not publicly available from the manufacturer, and must be determined by reverse-engineering (disassembly, trial-and-error, etc.).	 Undocumented information tends to change -- often dramatically -- between successive revisions of a product, since the manufacturer has no obligation to maintain compatibility in behavior which is not explicitly stated.)
	CF set on error
	    AX = error code (0Fh) (see #01680 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
SeeAlso: AH=19h,AH=3Bh,AH=71h,INT 15/AX=DE25h