RISC-V.

ISA Specification

The specifications shown below represent the current, ratified releases. Work is being done on GitHub.

• Volume 1, Unprivileged Spec v. 20191213  [PDF]
• Volume 2, Privileged Spec v. 20211203  [PDF]
• Recently ratified, but not yet integrated, extension specifications

Past ratified releases include the term “ratified” in the release tag.

Non-ISA Specifications

If  you are looking for a complete list of specifications, including our non-ISA specifications and our Compatibility Test Framework, visit the RISC-V Technical Specifications page.

RISC-V International is the global non-profit home of the open standard RISC-V Instruction Set Architecture (ISA), related specifications, and stakeholder community

More than 3,100 RISC-V members across 70 countries contribute and collaborate to define RISC-V open specifications as well as convene and govern related technical, industry, domain, and special interest groups.

RISC-V combines a modular technical approach with an open, royalty-free ISA — meaning that anyone, anywhere can benefit from the IP contributed and produced by RISC-V. As a non-profit, RISC-V does not maintain any commercial interest in products or services. As an open standard, anyone may leverage RISC-V as a building block in their open or proprietary solutions and services.

RISC-V does not take a political position on behalf of any geography. We are proud to see organizations from around the world working together in this new era of processor innovation. RISC-V was founded in 2015 as the RISC-V Foundation and is incorporated today as RISC-V International Association in Switzerland.

Understanding the RISC-V ISA Open Standard

At the base level, the RISC-V ISA and extensions ratified by RISC-V International are royalty free and open base building blocks for anyone to build their own solutions and services on. The RISC-V ISA and ratified extensions are provided under globally accepted open licenses that are permanently open and remain available for all.

Beyond RISC-V International, the community has opportunity to provide their own free or proprietary IP, implementations, solutions, and services for which RISC-V has no commercial or governance interest.

RISC-V International is wholly committed to design freedom, choice, and flexibility, and supports open architecture extensions to the RISC-V ISA. We do not support work on alternative versions of the RISC-V ISA.

Open source and global standards have a long history of success because they have a license framework that ensures anyone, anywhere can have ongoing access to them.