Fixed-point-cpp

A lightweight, header-only C++ class that implements fixed-point arithmetic as a replacement for floating-point operations in performance-critical or hardware-constrained environments.

---

💡 Motivation

Floating-point math is a brilliant invention... but let's face it — it's not always ideal.

In many situations, especially on microcontrollers or older hardware, floating-point operations:

• Consume more power
• Require more computational overhead
• May not be supported natively (no FPU)
• Can introduce rounding errors in places you don’t expect

So here’s an attempt at creating a simple fixed-point type, where we prioritize speed over precision, range, or safety. It’s not for every use case, but in low-level systems, embedded devices, or performance-critical inner loops — it just might shine. 🚀

---

⚙️ What It Is

This project provides a Fixed class using variable fractional bits (Q24.8 format included) to:

• Represent floats as integers under the hood
• Replace float/double types where feasible
• Gain some speed (especially on targets without FPUs)
• Keep things simple and educational

---

✨ Features

• Fixed-point math using integer ops
• Arithmetic: +, -, *, /
• Comparisons: <, >, ==, etc.
• Prefix/postfix ++ / --
• Casting to int and float
• min() and max() helpers
• std::ostream support (<<)
• Inline, header-only implementation
• Implementing the variable fractional precision using templates.

---

🧪 Example

#include "Fixed.hpp"
#include <iostream>

int main() {
    Fixed8_t a(10);          // from int
    Fixed8_t b(3.5f);        // from float

    std::cout << "a: " << a << ", b: " << b << "\n";
    std::cout << "a + b = " << (a + b) << "\n";
    std::cout << "a * b = " << (a * b) << "\n";

    if (a > b)
        std::cout << "a is greater than b\n";
}

---

🔧 How to Use

Just include the header:

#include "Fixed.hpp"

No extra dependencies. No build system required. Use with any modern C++ compiler: You can build the project using the provided Makefile.

✅ Build & Run:

make
./Fixed

🧹 Clean Build Files:

make clean     # removes object files
make fclean    # removes object files + binary
make re        # full rebuild

Alternatively, you can compile manually:

c++ -Wall -Wextra -Werror main.cpp -o Fixed

🛠️ TODO

Chosing between using int (2^32 bits) under the hood or long (2^64 bits) or even a more flexible hybrid structure (variable bits), probably using template for that.

Most IDEs highlights code in the .tpp files since it doesn't see the full difinition (no real compiling errors), I'll probably do a workaround (or not.. ).

Handle overflow cases gracefully.

Add unit tests (GoogleTest?...), I did provide the main.cpp for fast testing tho.

Explain the math behind fixed-point and and why Fixed shines(or send a PR and do it for me 😄)

📜 License

MIT — do whatever you want, just don’t blame me if it breaks.

❤️ Contribute

Floating point may not be the root of all evil, but this repo is open to improvement. Found a bug? Want to optimize the math? add more tests? Submit a PR or open an issue.