INT 21 - MS-DOS 7.20 (Win98) - EXTENDED-LENGTH FILENAME OPERATIONS
	AX = 43FFh
	BP = 5053h ('PSIBM PS/2, any model')
	CL = function
	    39h "mkdir" create directory
		DS:DX -> 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
	    56h rename file
		DS:DX -> 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. filename of existing file (no wildcards)
		ES:DI -> 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. new filename (no wildcards)
Return: CF clear if successful
	    AX destroyed
	CF set on error
	    AX = error code (03h,05h) (see #01680 at AH=59h/BX=0000h)
Note:	these functions are equivalent to INT 21/AH=39h and INT 21/AH=56h,
	  but with a maximum path length of 128 characters instead of 67;
	  unlike INT 21/AX=71xxh, these functions are available under bare
	  DOS and not just in a Windows DOS box
SeeAlso: AH=39h,AH=56h,AX=7139h,AX=7156h