Set up your SME2 development environment

Choose your SME2 setup: native or emulated

To build or run SME2-accelerated code, first set up your development environment. This section walks you through the required tools and two supported setup options:

• Native SME2 hardware - build and run directly on a system with SME2 support, see Devices with native SME2 support

• Docker-based emulation - use a container to emulate SME2 in bare metal mode (without an OS)

Download and explore the code examples

To get started, begin by downloading the code examples .

Now extract the archive, and change directory to: code-examples/learning-paths/cross-platform/multiplying-matrices-with-sme2.

    

        
        
tar xfz code-examples-main-learning-paths-cross-platform-multiplying-matrices-with-sme2.tar.gz -s /code-examples-main-learning-paths-cross-platform-multiplying-matrices-with-sme2/code-examples/
cd code-examples/learning-paths/cross-platform/multiplying-matrices-with-sme2

    

The directory structure should look like this:

    

        
        
code-examples/learning-paths/cross-platform/multiplying-matrices-with-sme2/
├── .clang-format
├── .devcontainer/
│   └── devcontainer.json
├── .git/
├── .gitignore
├── Makefile
├── README.rst
├── docker/
│   ├── assets.source_me
│   ├── build-all-containers.sh
│   ├── build-my-container.sh
│   └── sme2-environment.docker
├── hello.c
├── main.c
├── matmul.h
├── matmul_asm.c
├── matmul_asm_impl.S
├── matmul_intr.c
├── matmul_vanilla.c
├── misc.c
├── misc.h
├── preprocess_l_asm.S
├── preprocess_vanilla.c
├── run-fvp.sh
└── sme2_check.c

    

Among other files, it includes:

• Code examples.
• A Makefile to build the code.
• run-fvp.sh to run the FVP model.
• A docker directory containing:
  • assets.source_me to provide toolchain paths.
  • build-my-container.sh, a script that automates building the Docker image from the sme2-environment.docker file. It runs the Docker build command with the correct arguments so you don’t have to remember them.
  • sme2-environment.docker, a custom Docker file that defines the steps to build the SME2 container image. It installs all the necessary dependencies, including the SME2-compatible compiler and Arm FVP emulator.
  • build-all-containers.sh, a script to build multi-architecture images.
• .devcontainer/devcontainer.json for VS Code container support.

Set up a system with native SME2 support

To run SME2 code natively, ensure your system includes SME2 hardware and uses a compiler version that supports SME2.

For the compiler, you can use Clang version 18 or later, or GCC version 14 or later. This Learning Path uses clang.

You can check your compiler version using the command:clang --version

Install Clang

Install Clang using the instructions below, selecting either macOS or Linux/Ubuntu, depending on your setup:

    

        
        

  sudo apt install clang
  

    

    

        
        

  brew install llvm
  

    

You are now all set to start hacking with SME2.

Set up a system using SME2 emulation with Docker

If your machine doesn’t support SME2, or you want to emulate it, you can use the Docker-based environment.

The Docker container includes both a compiler and Arm’s Fixed Virtual Platform (FVP) model for emulating code that uses SME2 instructions. You can either run the prebuilt container image provided in this Learning Path or build it yourself using the Docker file that is included.

If building manually, follow the instructions in the sme2-environment.docker file to install the required tools on your machine.

Install and verify Docker

To begin, start by checking that Docker is installed on your machine:

    

        
        docker --version
__output__Docker version 27.3.1, build ce12230

        
    

If the above command fails with an error message similar to “docker: command not found”, then follow the steps from the Docker install guide to install Docker.

Once you have confirmed that Docker is installed on your machine, you can check that it is working with the following:

    

        
        docker run hello-world
__output__Unable to find image 'hello-world:latest' locally
__output__latest: Pulling from library/hello-world
__output__c9c5fd25a1bd: Pull complete 
__output__Digest: sha256:940c619fbd418f9b2b1b63e25d8861f9cc1b46e3fc8b018ccfe8b78f19b8cc4f
__output__Status: Downloaded newer image for hello-world:latest
__output__
__output__Hello from Docker!
__output__This message shows that your installation appears to be working correctly.
__output__
__output__To generate this message, Docker took the following steps:
__output__ 1. The Docker client contacted the Docker daemon.
__output__ 2. The Docker daemon pulled the "hello-world" image from the Docker Hub.
__output__    (arm64v8)
__output__ 3. The Docker daemon created a new container from that image which runs the
__output__    executable that produces the output you are currently reading.
__output__ 4. The Docker daemon streamed that output to the Docker client, which sent it
__output__    to your terminal.
__output__
__output__To try something more ambitious, you can run an Ubuntu container with:
__output__ $ docker run -it ubuntu bash
__output__
__output__Share images, automate workflows, and more with a free Docker ID:
__output__ https://hub.docker.com/
__output__
__output__For more examples and ideas, visit:
__output__ https://docs.docker.com/get-started/

        
    

You can use Docker in the following ways:

• Directly from the command line - for example, when you are working from a terminal on your local machine.

• Within a containerized environment - by configuring VS Code to execute all the commands inside a Docker container, allowing you to work seamlessly within the Docker environment.

Run commands from a terminal using Docker

When a command is executed in the Docker container environment, you must prepend it with instructions on the command line so that your shell executes it within the container.

For example, to execute COMMAND ARGUMENTS in the SME2 Docker container, the command line looks like this:

    

        
        
docker run --rm -v "$PWD:/work" -w /work armswdev/sme2-learning-path:sme2-environment-v2 COMMAND ARGUMENTS

    

This invokes Docker, using the armswdev/sme2-learning-path:sme2-environment-v2 container image, and mounts the current working directory (the code-examples/learning-paths/cross-platform/multiplying-matrices-with-sme2) inside the container to /work, then sets /work as the working directory and runs COMMAND ARGUMENTS in this environment.

For example, to run make, you need to enter:

    

        
        
docker run --rm -v "$PWD:/work" -w /work armswdev/sme2-learning-path:sme2-environment-v2 make

    

Use an interactive Docker shell

The standard docker run commands can be long and repetitive. To streamline your workflow, you can start an interactive Docker session that allows you to run commands directly - without having to prepend docker run each time.

To launch an interactive shell inside the container, use the -it flag:

    

        
        
docker run --rm -it -v "$PWD:/work" -w /work armswdev/sme2-learning-path:sme2-environment-v2

    

You are now in the Docker container, and you can execute all commands directly. For example, the make command can now be simply invoked with:

    

        
        
make

    

To exit the container, simply hit CTRL+D. Note that the container is not persistent (it was invoked with --rm), so each invocation will use a container freshly built from the image. All the files reside outside the container, so changes you make to them will be persistent.

Develop with Docker in Visual Studio Code

If you are using Visual Studio Code as your IDE, the container setup is already configured with devcontainer/devcontainer.json.

Make sure you have the Microsoft Dev Containers extension installed.

Then select the Reopen in Container menu entry as shown below.

It automatically finds and uses .devcontainer/devcontainer.json:

Figure 1: Setting up the Docker container.

All your commands now run within the container, so there is no need to prepend them with a Docker invocation, as VS Code handles all this seamlessly for you.

Devices with native SME2 support

These Apple devices support SME2 natively.