If you have ever wanted to implement a RISC-V CPU core in about 600 lines of C, you’re in luck! [mnurzia]’s rv project does exactly that, providing a simple two-function API.

Technically, it’s a user-level RV32IMC implementation in ANSI C. There are many different possible flavors of RISC-V, and in this case is a 32-bit base integer instruction set (RV32I), with multiplication and division extension (M), and compressed instruction set extension (C).

There’s a full instruction list and examples of use on the GitHub repository. As for readers wondering what something like RISC-V emulation might be good for, it happens to be the not-so-secret sauce to running Linux on an RP2040.