The Sparse Synchronous Model Runtime

The Sparse Synchronous Model (SSM) is a deterministic real-time execution technique that allows explicit, precise timing control.

The source code for this library is hosted on GitHub at https://github.com/ssm-lang/ssm-runtime/tree/main.

Documentation

The generated documentation for this library maybe found at https://ssm-lang.github.io/ssm-runtime.

The code documentation is organized in terms of modules, which are listed at https://ssm-lang.github.io/ssm-runtime/modules.html. Note that these modules do not reflect how the documented code is organized in files. Instead, they are purely logical: they group together related families of types and symbols across C translation units and public/private interfaces.

The operation of this library was first described in:

Stephen A. Edwards and John Hui. The Sparse Synchronous Model. In Forum on Specification and Design Languages (FDL), Kiel, Germany, September 2020. http://www.cs.columbia.edu/~sedwards/papers/edwards2020sparse.pdf

Dependencies

The core runtime, which includes the scheduler and memory manager, is written in C99, without library dependencies. The top-level Makefile is used to compile and test this core library, and has the following dependencies:

• Some C99-compatible compiler (gcc required for testing)
• GNU make
• GNU Bash (required for testing)
• Doxygen (required for building documentation)
• Graphviz (required for building documentation)
• valgrind (required for testing)
• gcov (required for testing)

On Ubuntu, Debian, and other Linux distributions that use aptitude, these can be installed using:

sudo apt install build-essential gcc doxygen graphviz valgrind gcov

Platform-specific bindings are provided via the PlatformIO Core (CLI) toolchain manager; see their installation instructions. On Linux, make sure to install the 99-platformio-udev.rules.

Note that PlatformIO does not use the top-level Makefile to build the SSM runtime. Instead, it uses the top-level library.json manifest to compile this library as a PlatformIO package.

Quickstart

The top-level Makefile can be used to build the platform-generic library alone, without platform-specific bindings. To build just the library, just run:

make # `lib' is the default target

All build artifacts, including libssm.a, are placed in the build directory.

To run the included test suite, run the included test script:

./runtests.sh

To build and run any individual example in the examples/ directory, e.g., examples/fib.c:

make build/fib
./build/fib 5