Procedure Push(Item:Data);

    This pushes  Item  onto  the  stack.   If  debug  information  is on,
    a check to see if the stack is  full  is made.  If the stack is full,
    then the  unit  aborts  and  returns  an  error  message.   If  debug
    information is  off  (the  unit  checks  FINAL),  no  check  is  made
    and the unit will write to  the  stack  anyway,  probably  corrupting
    memory and possibly crashing the program.