DF               Define Farword                                     Directive

  DF name

     This directive defines a 48-bit pointer normally only used with the
     80386 (a segment selector followed by a 32-bit offset address). With
     it you can set aside 6 bytes of data that make up:

                o  An expression with a value from -140,737,488,355,328 to
                   281,474,976,710,655
                o  Uninitialized data (if you use the ? symbol)
                o  A segment:32-bit offset address

     The memory unit defined this way is known as an FWORD.