Function 39h            Create Directory (MKDIR)

    Creates a subdirectory by using the specified path.

        Entry   AH    = 39h
                DS:DX = Pointer to ASCIIZ directory name

        Return  AX = Error code, if CF is set
                     | 03h Path not found
                     | 05h Access denied (pathname exists)

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    Function 39h creates a subdirectory whose path is specified in
    the zero-terminated string at address DS:DX; the string length is
    limited to 64 characters. The string must be a valid DOS directory
    name; it may include a drive letter, but no wildcards.

    If any of the parent directories in the path does not exist, the
    directory is not created.