The RISC-V Instruction Set Manual is a specification document repository that contains the authoritative source for the RISC-V instruction set architecture.
The repository serves as the central source of truth for the RISC-V ISA, organized into three volumes covering unprivileged architecture, privileged architecture, and profiles. It maintains both officially ratified specifications and draft versions, with compiled outputs available as PDFs and HTML snapshots. The manual is written in TeX and built using Docker-based tooling, with alternative local and GitHub Actions build methods available. The repository also maintains a canonical registry of open-source RISC-V implementations' marchid CSR values.
Developers and architects implementing RISC-V systems should use this repository as their reference for instruction encoding, behavior, and system-level specifications. It is essential for anyone building RISC-V processors, compilers, emulators, or other tools that need authoritative ISA documentation. The repository distinguishes between official ratified versions published through RISC-V International and draft versions available through GitHub releases, allowing users to choose between stable specifications and the latest proposed changes. Older official versions are archived and accessible for historical reference.
The project maintains active development with regular updates to draft specifications and contributions from the RISC-V community. Build infrastructure relies on containerized Docker images to ensure reproducible documentation generation across different environments. The repository provides clear contribution guidelines and documentation developer resources to facilitate community participation in specification development and refinement.
