RISC-V Extensions update including 29 extensions to stabilize #1987
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a4lg force-pushed the riscv-extensions-2025.1 branch 2 times, most recently from c60bc59 to 25d43f0 Compare a4lg force-pushed the riscv-extensions-2025.1 branch from 25d43f0 to a35f1c8 Compare Contributor Author
Possible ConsiderationSome platform behavior extensions are hard to make a short, concise summary. Do we prefer to keep long(er than usual) descriptions? Or, do we just link to the RISC-V Profiles documentation and let it explain? My Current PositionI prefer the latter if allowed but mdbook design is confirmed not broken so the current approach (long descriptions) is okay for me. |
ehuss added the S-waiting-on-stabilization Contributor Author
| Ping. Can someone review this PR? |
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a4lg force-pushed the riscv-extensions-2025.1 branch from a35f1c8 to d27acfa Compare a4lg changed the title a4lg force-pushed the riscv-extensions-2025.1 branch from d27acfa to 5527d55 Compare Contributor Author
Amanieu approved these changes Sep 18, 2025
a4lg force-pushed the riscv-extensions-2025.1 branch from 5527d55 to 9d250ee Compare 
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| This PR was rebased onto a different master commit. Here's a range-diff highlighting what actually changed. Rebasing is a normal part of keeping PRs up to date, so no action is needed—this note is just to help reviewers. |
a4lg force-pushed the riscv-extensions-2025.1 branch from 9d250ee to 94395db Compare This commit directly corresponds to rust-lang/rust#145948. See that proposal for criteria of 29 new extensions. Notes (for the Rust reference): * Updated existing `a` and `c` to imply its subset(s). * `a` equals `zalrsc` and `zaamo` combined (imply both from `a`). * The C extension always implies the Zca extension and conditionally implies Zcf and/or Zcd extensions (on RISC-V) but `c` (Rust target feature) only implies `zca` as both `zcf` and `zcd` are not to be stabilized on this proposal. * For each extension, linked to the first document containing it with the ratified state. For instance, all extensions present in the RVA23 profiles link to (3) (despite that they are present in (2)) because they were not ratified at the time when (2) is published. References: 1. RISC-V Instruction Set Manual (version 20250508): <https://github.com/riscv/riscv-isa-manual/tree/20250508> 2. RISC-V Profiles (version 1.0 - RVA23 profiles were not ratified at the time): <https://github.com/riscv/riscv-profiles/tree/v1.0> 3. RISC-V Profiles (RVA23/RVB23-ratified version): <https://github.com/riscv/riscv-profiles/tree/rva23-rvb23-ratified>
a4lg force-pushed the riscv-extensions-2025.1 branch from 94395db to 317dbf6 Compare Contributor Author
| Rebased and made some clarification in the commit message (the same as the edited initial comment). |
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This commit directly corresponds to rust-lang/rust#145948.
See that proposal for criteria of 29 new extensions.
Notes (for the Rust reference)
aandcto imply its subset(s).aequalszalrscandzaamocombined (imply both froma).c(Rust target feature) only implieszcaas bothzcfandzcdare not to be stabilized on this proposal.For instance, all extensions present in the RVA23 profiles link to (3) (despite that they are present in (2)) because they were not ratified at the time when (2) is published.
References
https://github.com/riscv/riscv-isa-manual/tree/20250508
https://github.com/riscv/riscv-profiles/tree/v1.0
https://github.com/riscv/riscv-profiles/tree/rva23-rvb23-ratified