Boost.Multiprecision tries hard to implement
for all types as far as possible and meaningful because experience with Boost.Math
has shown that this aids portability.
standard library defines
in section 18.3.2.
This in turn refers to the C standard SC22/WG11 N507 DRAFT INTERNATIONAL ISO/IEC STANDARD WD 10967-1 Information technology Language independent arithmetic Part 1: Integer and floating-point arithmetic.
That C Standard in turn refers to
There is a useful summary at C++ reference.
The chosen backend often determines how completely
Compiler options, processor type, and definition of macros or assembler instructions to control denormal numbers will alter the values in the tables given below.