Fast Half Float (fhf)

A small library for quickly packing and unpacking half-precision floating point values.

The implementation is based on the Fast Half Float Conversions paper by Jeroen van der Zijp, referenced by the Wikipedia article on half-precision floating point.

The only distinguishing feature of this implementation is that it uses the compile-time lookup table feature of C++20. There are no classical unit tests, just some static_assert's sprinkled around.

Usage

CMake

The easiest way to include this library in your project is to use the CMake's FetchContent functionality, for example:

cmake_minimum_required(VERSION 3.16)
project(integration_test)

set(CMAKE_CXX_STANDARD 11)

include(FetchContent)
FetchContent_Declare(
    fhf
    GIT_REPOSITORY https://github.com/yowidin/fast-half-float
    GIT_TAG master
)
FetchContent_MakeAvailable(fhf)

add_executable(test main.cpp)
target_link_libraries(test PRIVATE FastHalfFloat::library)

C++

You can now be able to pack and unpack the half-precision float values:

#include <fhf/fhf.hh>

#include <iostream>
#include <limits>

void foo() {
   auto h = fhf::pack(std::numeric_limits<float>::infinity());
   std::cout << "Infinity:" << std::hex << h << std::endl;

   h = fhf::pack(-std::numeric_limits<float>::infinity());
   std::cout << "-Infinity:" << std::hex << h << std::endl;

   auto f = unpack(0x3C00);
   std::cout << "0x3C00:" << f << std::endl;
}