These functions allow users to test conformance to IEEE Std 754-1985. Their use is not otherwise recommended.
logb(
x) returns
x's exponent
n, a signed integer converted to double-precision floating-point.
logb(
±infinity) = +infinity;
logb(
0) = -infinity with a division by zero exception.
scalbn(
x,
n) returns
x∗(2**
n) computed by exponent manipulation.
significand(
x) returns
sig, where
x :=
sig ∗ 2**
n with 1 ≤
sig < 2.
significand(
x) is not defined when
x is 0, ±infinity, or NaN.