[znwu]

RVA22 Profile: https://github.com/riscv/riscv-profiles/blob/main/profiles.a...

Zba and Zbb are both mandatory extensions. Zbc, Zbkb, Zbkc, Zbkx are all supported extensions. Zba and Zbb contain most useful bitmanip instructions. For example, POPCOUNT is in Zbb.

Implementations are free to choose their extension combinations and go out of standard profiles. But doing so will void them from mainstream *nix support.

Edit: Also for the already sold units, there is a RVA20 profile without any bitmanip which most of them will match. You can assume no newer application uarch will use RVA20 since year 2022.

[ncmncm]

Thank you, this is very helpful. I am more optimistic about the usefulness of RISC-V than before reading this.