INT 21,39 - Create Subdirectory (mkdir)

AH = 39h

DS:DX = pointer to ASCIIZ path name

on return:

CF = 0 if successful

= 1 if error

AX = error code (see ~DOS ERROR CODES~)

- creates specified subdirectory

- returns error if directory already exists, element of the path

is not found, directory full or write protected disk