EXPONENT (real-number)

  Class:  Elemental function - Generic

  Returns the exponent part of the argument when represented as a
  model number.

  The result is of type default integer.  If the argument is not
  equal to zero, the result value is the exponent part of the
  argument.  The exponent must be within default integer range;
  otherwise, the result is undefined.

  If the argument is zero, the exponent of the argument is zero.
  For more information on the exponent part in the real model, see
  the HP Fortran for OpenVMS Language Reference Manual.

  Examples:

  EXPONENT (2.0) has the value 2.

  If 4.1 is a REAL*4 value, EXPONENT (4.1) has the value 3.