Flute

A C++20 fixed-point single header library, for embedded devices.

⚠️ This project is a work in progress, use at your own risk.

Description

Flute is a C++20 fixed-point library. It aims to provide a modern interface that allows to deal with fixed-point arithmetic. It is meant to be used on systems that don't have an FPU (floating-point unit), such as micro-controllers.

Flute is a bit different from other fixed-point libraries. It includes utilities for look-up tables (LUT, hence the name "flute").

Features

• Zero-overhead: You only pay for what you need. For instance (real-world example), compiling for an ARM Cortex-M3 using GCC 13.2, flute allows to multiply an integer and a ufixed<12, 20> as fast as a regular 32-bit integer multiplication. Compared to multiplying an integer with a 32-bit float, this allows to save about 1277 bytes in the compiled firmware.
• Embedded-friendly: The STL is not required. Flute only needs a few C++ headers: array, concepts, limits, and type_traits.
• Modern C++ standards: Requires C++20. Concepts make the code more reliable and provide readable error messages. Moreover, modern C++ is key to achieve optimal performance.
• Compile-time evaluation: Everything is constexpr! This has a very positive impact on performance too.
• Header-only library: No need to link the library, simply include flute.hpp into your .cpp files.
• Policy-based design: Some fixed-point operations require to make choices, especially regarding overflow.

Usage

Prerequisites

Since this is a header only library, all you need is a C++20 compiler. This library has only been tested with GCC 13.2 (x86-64 and arm-none-eabi). It should compile with GCC 10 and Clang 16.

Installing

It's a single header library, so there's nothing to install. All you need is to include flute.hpp in your C++ files.

Example

#include "flute.hpp"

int main()
{
  using namespace flute;

  constexpr ufixed<16,16> pi{3.1415926};
  constexpr auto two_pi = 2 * pi;

  static_assert((two_pi - pi).as<double>() == pi.as<double>());
}

Building the project

It's a header-only library, include flute.hpp and build your source files as usual.

Documentation

No documentation yet, but there will be one for sure.

Running the tests

Contributing

Versioning

This project will make use of SemVer for versioning.

Authors

• Ronna Technologies - @RonnaTechnologies
• Jeremy Oden - @SpintroniK

License

This project is licensed under the MIT license.