GitHub - copy/v86: x86 virtualization in your browser, recompiling x86 to wasm on the fly
v86 emulates an x86-compatible CPU and hardware. Machine code is translated to WebAssembly modules at runtime in order to achieve decent performance. Here's a list of emulated hardware: An x86-compatible CPU. The instruction set is around Pentium III level, including full SSE2 support.
https://github.com/copy/v86