VMS Help PASCAL, Attributes, Allocation, AT  *Conan The Librarian (sorry for the slow response - running on an old VAX)

  The AT attribute  specifies  that  Compaq  Pascal  allocates  no
  storage  for the object (storage has already been allocated) and
  that it resides at the exact, specfied address.

  Syntax:

     AT( n )

  The exact address is specified by  the  constant  expression  n.
  Variables representing machine-dependent entities are frequently
  given the AT attribute.

  See the  "Compaq  Pascal  Language  Reference  Manual"  for  the
  complete description of using the AT attribute.