Real and complex numbers are floating-point representations.

  The exponent for REAL(KIND=4) (or REAL*4) (F_floating) and DOUBLE
  PRECISION (REAL(KIND=8) or REAL*8) (D_floating) formats is stored
  in binary excess 128 notation.  Binary exponents from -127 to 127
  are represented by the binary equivalents of 1 through 255.

  The exponent for the DOUBLE PRECISION G_floating format and
  T_floating format is stored in binary excess 1024 notation.  The
  exponent for the REAL*16 format is stored in binary excess 16384
  notation.  In DOUBLE PRECISION (G_floating) format, binary exponents
  from -1023 to 1023 are represented by the binary equivalents of 1
  through 2047.  In REAL*16 format, binary exponents from -16383 to
  16383 are represented by the binary equivalents of 1 through 32767.

  For floating-point format, fractions are represented in
  sign-magnitude notation, with the binary radix point to the left of
  the most significant bit for F_floating, D_floating, and G_floating,
  and to the right of the most significant bit for S_floating and
  T_floating.  Fractions are assumed to be normalized, and therefore
  the most significant bit is not stored.  This bit is assumed to be 1
  unless the exponent is 0.  in which case the value represented is
  either zero or is a reserved operand.

  REAL(KIND=4) (or REAL*4) numbers occupy four contiguous bytes and
  the precision is approximately one part in 2**23, that is,
  typically 7 decimal digits.

  DOUBLE PRECISION (D_floating) numbers occupy eight contiguous bytes
  and the precision is approximately one part in 2**55, that is,
  typically 16 decimal digits.

  DOUBLE PRECISION G_floating numbers occupy eight contiguous bytes
  and the precision is approximately one part in 2**52, that is,
  typically 15 decimal digits.

  REAL*16 (H_floating) numbers occupy sixteen contiguous bytes and
  the precision is approximately 2**112, that is, typically 33
  decimal digits.

  For more information on real data type ranges, see DATA CONSTANTS
  REAL and DATA CONSTANTS DOUBLE_PRECISION in this Help file.