WasMetal

A project to build a bare metal physical implementation of WebAssembly. That’s right, a WebAssembly CPU. Inspired in part by this amazing talk.

WasMetal is being revived under Millillion in 2026. It implements WebAssembly Core 3.0 instructions in a clocked SystemVerilog stack machine, with a software loading and validation front end.

Completed work lives on main. Temporary development branches are integrated into main and pushed before a task is finished; the README is reviewed with every commit. Main-branch verification runs finish before queued code changes are tested, so frequent commits do not cancel active regressions. Newer pushes can replace an older pending run.

Current status

The CPU now implements integral floating-point rounding directly in the IEEE encoding. All 259 official suites pass without memory stalls and with three wait states, with [every…