The $XABFHC_STORE macro moves user-specified values into fields
    of the specified XABFHC. The expanded $XABFHC_STORE code executes
    at run time on a previously initialized (allocated) XABFHC, in
    contrast to the $XABFHC macro, which initializes a XABFHC at
    assembly time. The $XABFHC_STORE macro must reside in a code
    program section.

    Format

      $XABFHC_STORE  XAB=xabfhc-address,

                     NXT=next-xab-address