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riscv / riscv-crypto

RISC-V cryptography extensions standardisation work.
https://wiki.riscv.org/x/MVcF
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Is "Vector Bit-manipulation used in Cryptography" an accurate name for Zvbb? #342

Closed topperc closed 1 year ago

topperc commented 1 year ago

As I understand it Zvbb was originally Zvkb and late some non-cryptography instructions like vcpop.v, vclz.v, and vctz.v were added to it to form Zvbb.

I think the cryptography reference should be dropped from the expanded name and instead it should be something like "Vector Basic Bit-manipulation".

nibrunieAtSi5 commented 1 year ago

I agree that it would make more sense to remove the mention to "cryptography", in particular because the extension is no longer prefixed by Zvk. However I do not know if this is just a cosmetic change or if it will have larger impact on other deliverables required in the on-going ratification process (which could make the change less straightforward).

nibrunieAtSi5 commented 1 year ago

If we go done this road we may need to update the description of the extension as well (which should have less impact):

General purpose bit-manipulation instructions which are essential for implementing common cryptographic workloads securely & efficiently.

To maybe:

General purpose basic bit-manipulation instructions, some of which are essential for implementing common cryptographic workloads securely & efficiently and others extend the generic bit manipulation capabilities of RISC-V on vectors.

https://github.com/riscv/riscv-crypto/blob/master/doc/vector/riscv-crypto-vector-zvbb.adoc

aamartin0000 commented 1 year ago

It might also be worth noting that most of the instructions in Zvbb have corresponding scalar instructions in Zbb (and, in some cases, Zbkb). It's not a perfect correspondence though.

nibrunieAtSi5 commented 1 year ago

Note: Following a discussion between the Architecture Review Committee and the TG chair, a new sub-extension containing the instructions for the original Zvkb is going to be split out of Zvbb. This may be a good time to clarify naming.

kdockser commented 1 year ago

Thanks for the suggestion, Craig. We have renamed Zvbb as you suggested.

The specification has been updated such that Zvkb is a proper subset of Zvbb. Zvkb is the mnemonic for "Vector Cryptography Bit-manipulation" and Zvbb is the mnemonic for "Vector Basic Bit-manipulation"