SIGN (arg1, sign-arg2)

  Class:  Elemental function - Generic

  Assigns the sign of the second argument to the absolute value of
  the first.

  If the second argument is of type real and zero, the value of the
  result is |arg1|.  However, if the processor can distinguish
  between positive and negative real zero and the compiler option
  /ASSUME=MINUS0 is specified, the following occurs:

   o  If the second argument is positive real zero, the value of the
      result is |arg1|.

   o  If the second argument is negative real zero, the value of the
      result is -|arg1|.

  +------+---------+----------+------------+-------------+
  | Args | Generic | Specific |  Argument  | Result Type |
  +------+---------+----------+------------+-------------+
  |  2   |  SIGN   |  --      | INTEGER*1  | INTEGER*1   |
  |      |         | IISIGN   | INTEGER*2  | INTEGER*2   |
  |      |see note | ISIGN    | INTEGER*4  | INTEGER*4   |
  |      |         | KISIGN   | INTEGER*8  | INTEGER*8   |
  |      |         | SIGN     | REAL*4     | REAL*4      |
  |      |         | DSIGN    | REAL*8     | REAL*8      |
  |      |         | QSIGN    | REAL*16    | REAL*16     |
  +------+---------+----------+------------+-------------+

  NOTE: Or JISIGN.  For compatibility with older versions
        of Fortran, ISIGN can also be specified as a generic
        function.