The  INITIALIZE  attribute  can  be  applied  to  procedures  to
  indicate  that  the  procedure  is  to be called before the main
  program is entered.  A compilation unit might include any number
  of  INITIALIZE  procedures,  all  of  which  are  called  in  an
  unspecified order before the main program is entered.

  See the "HP Pascal Language Reference Manual" for  the  complete
  description of using the INITIALIZE attribute.