µfck is a minimal bios including a brainf*ck interpreter for Arduino Uno (ATmega 328p) with the total binary size of less than 1000 bytes.

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This is my first project here on Hackaday, I hope I did not forget something.

Yet Another Brainfck Project.

µfck is a minimalistic project and only a proof-of-concept that an individual can have a binary for the Arduino smaller than 1000 bytes. As the default Arduino IDE outputs a giantic blob of binary – without any usable content - always was a no-go for me.
The output binary only includes the C-initialization code, the Serial Communication initialization and the Brainfck Interpreter - which was also handcrafted by me. Nothing else, not even a C library.
Please feel free to comment, criticize and ask any questions.
Also see my story (added later) how µfck was created.

Compiled with:

  • 'avr-gcc -v' gcc version 4.9.2 (GCC)
  • Arduino SDK 1.6.13

  • The Beginning

    wille.io01/02/2017 at 18:39 0 comments

    This was my first try, code that does nothing:

    Then I compiled it to see in what size it comes out:

    What? That’s hughmungus! That can’t be it.

    The basic disassembly told me nothing what caused that giantic blob.

    Adding the size optimization flag didn’t do much. 31 bytes saved. If I would add a little functionality that would kill the 1024 bytes.

    ObjCopy it into Intel Hex will result in a minimalistic 30 bytes, that’s impressive for hex in text.

    But extracting it into binary is even better!

    2 bytes is more my league!

    Taking a look at the hex output:

    On which 08 95 is the return oft he main function. So I guess it works.

    The next steps were a little bit more complicated, as I wanted Serial Communication for my Brainfck Interpreter. So I copied all relevant code and munched it together, resulting in a really small bunch of code.

    (It works :)

    After the Serial Communication was working, I went on to build the Brainfck Interpreter. But at first I wrote it for the x86 Architecture to have faster builds to test. I took a look at Wikipedia on how these ‚Opcodes‘ work. After a few minutes I came to the famous ‚while‘ opcode, which is a little more complicated. I used a stack for the while-calles, as I like the CPU-way of doing stuff (me, as a mostly low-level developer).

    (Basic Example Debug Output for Testing)

    After flashing my final results, I wanted to cry:

    But after I remembered that there were a whole bunch of non-PROGMEM Debug String, I took them out and flashed it..

    Yay, success! Done! :)

View project log

  • 1
    Step 1

    It's easy to feed your Arduino Uno with µfck.
    µfck comes with an pre-inserted brainfck code which prints a simple text. Feel free to enter your own code or add your code to load it from eeprom.

    Clone from

  • 2
    Step 2

    Run make install with the following arguments:

    • Specify your Device to communicate and flash the binary with it: DEVICE=% Your Serial Device % [examples => Linux: /dev/ttyACM3; Windows: COM6]
    • Your AVR Dude Flash Configuration File: DUDE_CFG=%Your AVR Dude Configuration File% [located in your Arduino SDK folder + "Arduino/hardware/tools/avr/etc/avrdude.conf"]
  • 3
    Step 3

    Open the Terminal Emulator of your choice and open the previously selected serial device at 9600 baud.

View all 3 instructions

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