RISC-V (pronounced “risk-five”) is a license-free, modular, extensible instruction set architecture (ISA). Originally designed for computer architecture research at Berkeley, RISC-V is now used in everything from $5 microcontroller boards to the pan-European supercomputing initiative. RISC-V is suitable for custom silicon chips, as a soft core in an FPGA, or as a high performance software Virtual Machine. riscv.org