Simple sample

The minimal WAMR application on Zephyr: the runtime is initialized, a WASM module embedded in the image as a C array is instantiated, and its main is called. Only the built-in libc is used, so the sample runs on boards without a file system or network stack.

The module is not checked in: wasm-app/main.c is compiled with the wasi-sdk during the build and the resulting test_wasm.wasm is turned into test_wasm.h under the build directory. Building the sample therefore requires a wasi-sdk; it is looked up in /opt/wasi-sdk and /opt/wasi-sdk-*, set WASISDK_ROOT (or WASI_SDK_DIR) if it lives elsewhere.

See the platform README for environment setup, workspace layout, native_sim / QEMU usage and the CONFIG_WAMR_* options.

What to look at

• prj.conf — the CONFIG_WAMR_* selections: interpreter, AOT, built-in libc and a 128 KB global heap pool.
• CMakeLists.txt — the application only adds its own sources; the runtime comes from the wasm-micro-runtime Zephyr module.
• boards/ — per-board Kconfig fragments. Add boards/<board-identifier>.conf for a new board, or put the settings in prj.conf if they are board independent.
• wasm-app/ — the source of the embedded module and the standalone CMake project that compiles it with the wasi-sdk.

The module allocates a buffer, formats a string into it and checks the result, returning 0 on success and 1 (allocation) or 2 (content mismatch) otherwise. The Zephyr application turns that, an exception or its own errors into an exit code and a PASS: / ERROR: line, see Reporting results.

Test status

The scenarios are declared in sample.yaml; twister decides the verdict from the console output. Last run with build_and_run.py on 2026-08-06:

Scenario	Simulator	Result
sample.wamr.simple	native_sim	passed
sample.wamr.simple	qemu_arc/qemu_arc_hs	passed

Build and run

west build . -b qemu_x86 -p always
west build -t run

build_and_run.sh wraps the same commands for a handful of boards, including the ones that need a non-default WAMR_BUILD_TARGET or -DWAMR_BUILD_AOT=0:

./build_and_run.sh qemu_arc

Expected output

*** Booting Zephyr OS build v3.7.0 ***
Hello world!
buf ptr: 0x1458
buf: 1234
PASS: the wasm module ran to completion
elapsed: 10