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

  The BITSIZE function returns an integer value that indicates the
  number  of  bits  that  would  be allocated for one field of the
  specified type in a packed record or if the  specified  variable
  appeared as a field in a packed record.

  Syntax:

  BITSIZE( x )

  The parameter 'x' can be a variable or any type identifier.