2025/cable

" Created by Adrian Cable, this tool implements a virtual machine in just 366 bytes of C code. It is designed to evoke surprise and wonder, intentionally prioritizing minimalism and obfuscation over production readiness.

5GB RAM, an 800x512 resolution graphics card, a real time clock, keyboard driver, and pre-emptive multitasking. It is capable of running complex software, including Linux and DOOM, as well as previous IOCCC-winning entries. The VM operates as a One Instruction Set Computer (OISC) based on a variant of the SUBLEQ architecture, with an added indirect addressing mode. This design allows the virtual machine to achieve Turing completeness without self-modifying code, supporting reentrant functions as required by modern operating systems. The emulator features a memory-mapped register bank, framebuffer graphics, keyboard input, interrupts, and timers.

2025/cable is delivered as C source code with a Makefile, intended to be compiled and run from the command line. The only stated dependency is the SDL3 graphics library, which is required for portable graphics output. Users can build the program using standard tools and run it by piping boot images into the executable. Sample boot images include demonstrations such as Mandelbrot and Pong, as well as a downloadable Linux image. The tool is compatible with Linux and macOS environments, with installation instructions for SDL3 provided for both platforms.

This entry is explicitly not intended for production use, but rather as a programming challenge and a demonstration of what can be achieved with extreme code compactness and obfuscation. It is aimed at developers, enthusiasts, and participants in programming contests who are interested in virtual machines, code obfuscation, and minimalistic C programming.