compilers

3 Articles

A console is shown displaying a system’s startup information, followed by “Booting from Hard Disk …”, “Hello World!” in a green font, and “The keyboard is working!”

A Forth OS In 46 Bytes

May 27, 2025 by 26 Comments

It’s not often that we can include an operating system in a Hackaday article, but here’s the full 46-byte source of [Philippe Brochard]’s 10biForthOS in 8086 opcodes:

50b8 8e00 31d8 e8ff 0017 003c 0575 00ea
5000 3c00 7401 eb02 e8ee 0005 0588 eb47
b8e6 0200 d231 14cd e480 7580 c3f4

Admittedly, this is quite a minimal operating system. It’s written for the Intel 8086, and consists of a Forth implementation with only two instructions: compile (1) and execute (0). It can receive commands over a serial connection or from a keyboard. This allows a host computer to load more complex software onto it, one byte at a time. In particular, [Philippe] provides instructions for loading more advanced compilers, such as subleq-eForth for a more complete Forth implementation, or SectorC for C programming. He’s also written a 217-byte port of the OS to Linux Intel x64.

[Philippe] doesn’t take a strong stance on whether this should technically qualify as a Forth implementation, given that the base implementation lacks stacks, dictionaries, and the ability to define words. However, it does have an outer and inner interpreter, the ability to compile and execute code, and most importantly, “the simplicity and hacky feeling of Forth.”

[Philippe] writes that this masterpiece of minimalism continues the tradition of the minimal Forth implementations we’ve covered before. We’ve even seen Forth run on an Arduino.

DIY Forth On Arduino

July 8, 2021 by 32 Comments

On a recent rainy afternoon, [Thanassis Tsiodras] decided to build his own Forth for the Arduino to relieve the boredom. One week of intense hacking later, he called it done and released his project as MiniForth on GitHub. [Thanassis] says he was inspired by our series of Forth articles from a few years back, and his goal was to build a Forth interpreter / compiler from scratch, put it into a Blue Pill microcontroller. That accomplished, he naturally decides to squeeze it into an Arduino Uno with only 2K of RAM.

Even if you are ambivalent about the Forth language, [Thanissis]’s project has some great ideas to check out. For example, he’s a big proponent of Makefile automation for repetitive tasks, and the project’s Makefile targets implements almost every task needed for development, building and testing his code.

Some development and testing tasks are easier to perform on the host computer. To that end, [Thanassis] tests his programs locally using the simavr simulator. The code is also portable, and he can compile it locally on the host and debug it using GDB along with Valgrind and AddressSanitizer to check for memory issues. He chose to write the program in C++ using only zero-cost abstractions, but found that compiling with the ArduinoSTL was too slow and used too much memory. No problem, [Thanassis] writes his own minimalist STL and implements several memory-saving hacks. As a final test, the Makefile can also execute a test suite of Forth commands, including a FizzBuzz algorithm, to check the resulting implementation.

Here’s a short video of MiniForth in action, blinking an LED on an UNO, and the video below the break shows each of the various Makefile tasks in operation. If you want to learn more, check out Elliot Williams’s Forth series which inspired [Thanassis] and this 2017 article discussing several different Forth implementations. Have you ever built your own compiler? Let us know in the comments below.

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Frances Allen Optimised Your Code Without You Even Knowing

August 25, 2020 by 9 Comments

In 2020, our digital world and the software we use to create it are a towering structure, built upon countless layers of abstraction and building blocks — just think about all the translations and interactions that occur from loading a webpage. Whilst abstraction is undoubtedly a great thing, it only works if we’re building on solid ground; if the lower levels are stable and fast. What does that mean in practice? It means low-level, compiled languages, which can be heavily optimised and leveraged to make the most of computer hardware. One of the giants in this area was Frances Allen, who recently passed away in early August. Described by IBM as “a pioneer in compiler organization and optimization algorithms,” she made numerous significant contributions to the field. Continue reading “Frances Allen Optimised Your Code Without You Even Knowing” →