StateOS is free, extremely simple and very fast real-time operating system (RTOS) designed for deeply embedded applications.

ARM Cortex-M, STM8.

StateOS was inspired by the concept of a state machine. Procedure executed by the task (task state) doesn't have to be noreturn-type. It will be executed into an infinite loop. There's a dedicated function for immediate change the task state (task function).

All documentation is contained within source files, in particular header files.

Building an application for a specific compiler is realised using the appropriate makefile script.

• kernel can operate in preemptive or cooperative mode
• kernel can operate with 16, 32 or 64-bit timer counter
• kernel can operate in tick-less mode
• implemented basic protection using MPU (use nullptr, stack overflow)
• implemented functions for asynchronous communication with unmasked interrupt handlers
• spin locks
• once flags
• events
• signals with protection mask
• flags (any, all, protect, ignore)
• barriers
• semaphores (binary, limited, counting)
• mutexes with configurable type, protocol and robustness
• fast mutexes (error checking)
• condition variables
• read/write locks
• memory pools
• raw buffers
• message queues
• mailbox queues
• event queues
• job queues
• timers (one-shot, periodic)
• hierarchical state machine
• cmsis-rtos api
• cmsis-rtos2 api
• nasa-osal support
• c++ wrapper
• support for std::thread
• all documentation is contained within source files, in particular header files
• examples and templates are in separate repositories on GitHub
• archival releases on sourceforge

• std::thread, std::jthread, std::stop_callback, std::this_thread, ...
• std::mutex, std::shared_mutex, std::condition_variable, ...
• std::binary_semaphore, std::counting_semaphore, ...
• std::lock_guard, std::unique_lock, std::shared_lock, ...
• std::future, std::promise, std::assync, ...
• std::barrier, std::latch, ...
• std::chrono, ...
• thread local storage (thread_local)
• and more ...

This project is licensed under the terms of the MIT License (MIT).