Procedure GotoPrev;

    Moves to the previous  item  in  the  list.   If  the current item is
    at the front of the list when  calling  this, the current item points
    before the start of the  list.   You  can  then insert an item before
    the first item in the list.

    The  list  is  not   circular.    Calling   GotoPrev   when  pointing
    before the front of the list is not permitted.