The intx header-only C++20 library provides allocation-free extended precision integer types. They are implemented as arrays of std::uint64_t words and closely match the behavior of built-in types.

This is a bit packing library. Bit packing is the process by which you take arrays of (32-bit) integers that fit in [0,2^L) and you write them out using as close to L bits per integer as possible. For ...