Intel(R) Fortran Compiler for Linux* Systems User's Guide Volume I ...

Intel® Fortran Compiler for Linux* Systems User's Guide, Volume I: Building
Applications
Native IEEE* Floating-Point Representations
Native IEEE* Floating-Point
Representations Overview
The REAL(4) (IEEE* S_floating), REAL(8) (IEEE T_floating), and REAL(16)
(IEEE-style X_floating) formats are stored in standard little endian IEEE binary
floating-point notation. (See IEEE Standard 754 for additional information about
IEEE binary floating point notation.) COMPLEX() formats use a pair of REAL
values to denote the real and imaginary parts of the data.
All floating-point formats represent fractions in sign-magnitude notation, with the
binary radix point to the right of the most-significant bit. Fractions are assumed to
be normalized, and therefore the most-significant bit is not stored (this is called
"hidden bit normalization"). This bit is assumed to be 1 unless the exponent is 0.
If the exponent equals 0, then the value represented is denormalized
(subnormal) or plus or minus zero.
Intrinsic REAL kinds are 4 (single precision), 8 (double precision), and 16
(extended precision), such as REAL(KIND=4) for single-precision floating-point
data. Intrinsic COMPLEX kinds are also 4 (single precision), 8 (double precision),
and 16 (extended precision).
To obtain the kind of a variable, use the KIND intrinsic function. You can also use
a size specifier, such as REAL*4, but be aware this is an extension to the Fortran
95 standard.
If you omit certain compiler options, the default sizes for REAL and COMPLEX
data declarations are as follows:
• For REAL data declarations without a kind parameter (or size specifier),
the default size is REAL (KIND=4) (same as REAL*4).
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