Everybody is familiar with commercial licensing from traditional processor IP vendors such as Arm, Cadence, and Synopsys. But in discussing the RISC-V Open Instruction Set Architecture (ISA), there is widespread confusion of terminology with RISC-V often being described as “open source.” Some have even accused vendors of commercial RISC-V IP such as Codasip or Andes as not being in the spirit of RISC-V. But what is reality?
Let’s look at definitions briefly. An open standard like C, Verilog, or HTTP is defined by a document that is maintained by an independent organization. Thus, C is maintained by ISO, Verilog by IEEE, and HTTP by IETF. These organizations maintain the technical standards using a set of impartial rules. Such open standards are generally freely accessible.