VMS Help FORTRAN, Intrinsic Procedures, IEOR  *Conan The Librarian (sorry for the slow response - running on an old VAX)

  IEOR (integer, integer)

  A function that performs an exclusive OR of the arguments on a bit
  by bit basis.

  +------+---------+----------+------------+-------------+
  | Args | Generic | Specific |  Argument  | Result Type |
  +------+---------+----------+------------+-------------+
  |  2   | IEOR    | IIEOR    | INTEGER*2  | INTEGER*2   |
  |      |         | JIEOR    | INTEGER*4  | INTEGER*4   |
  +------+---------+----------+------------+-------------+