Function 43h (67)        Get or Set File Attributes (CHMOD)

    Gets or sets the attributes of a specified file.

     1.  To get attributes

       On entry:      AH         43h
                      AL         00h
                      DS:DX      Pointer to filespec (ASCIIZ string)

       Returns:       CX         File's attributes, or
                      AX         Error code, if CF is set

     2.  To set attributes

       On entry:      AH         43h
                      AL         01h
                      CX         Desired attributes
                      DS:DX      Pointer to filespec (ASCIIZ string)

       Returns:       AX         Error code, if CF is set

       Error codes:   1          Invalid function code
                      2          File not found
                      3          Path not found
                      5          Access denied

                      Call Function 59h for extended error code information
                      (DOS 3.0 and above).

       Network:       To change any attribute bit other than archive,
                      requires Create access rights.

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    This function returns or sets the attribute byte of the specified
    file. To determine the current attributes, put 00h in AL; the
    attribute byte is returned in CX. To set attributes, put 01h in AL and
    the desired attribute byte in CX.

       Notes:         The CX register specifies the attribute of the file
                      you're creating, as follows:

                               CX         Attribute specified
                               00h        Normal
                               01h        Read-only
                               02h        Hidden
                               04h        System
                               20h        Archive

                      Sum the values to combine attributes.

                      Setting any of the bits other than the above will
                      generate an error.