Clone, build the x86 development example, then run on hardware.
git clone https://github.com/SuperTinyKernel-RTOS/stk
STK has an x86 development mode, so you can build and run examples without hardware. See the Quick Start in the README for the exact commands.
Use Git and CMake, copy the files manually, or sparse-clone only the kernel:
git clone --depth 1 --filter=blob:none --no-checkout https://github.com/SuperTinyKernel-RTOS/stk.git cd stk git sparse-checkout init --cone git sparse-checkout set stk git checkout
Platform code lives in stk/src/arch and stk/include/arch. Ready examples exist for STM32 and Raspberry Pi Pico 2 W (including TrustZone).