VMS Help PASCAL, /SYNCHRONOUS_EXCEPTIONS D=/NOSYNCHRONOUS_EXCEPTIONS  *Conan The Librarian (sorry for the slow response - running on an old VAX)

                                   OpenVMS Alpha Only
  /NOSYNCHRONOUS_EXCEPTIONS

  Specifies that the compiler should generate code to insure  that
  exceptions  are  reported as near as possible to the instruction
  that generated the  exception.   This  can  avoid  confusion  in
  tracing  the  source  of  an  exception,  however,  there  is  a
  performance penalty for using this qualifier.