RFR: 8316592: RISC-V: implement poly1305 intrinsic [v7]

[Andrew Haley]

On Fri, 10 Nov 2023 12:27:49 GMT, Hamlin Li <mli at openjdk.org> wrote:

>> The low 2 bits are 00.
>
> Ah, right, all clear! Thanks!
> 
> But this makes it harder or not that performant to vectorise poly3015 based on this implementation, as for example R will be R^4 or R^8 (depends on lane numbers we have at runtime), these restrictions designed by the author of poly1305 will not hold anymore.

Exactly so. Vectorizing poly1305 is not easy to do at all.

The key paper is Martin Goll and Shay Gueron. _Vectorization of Poly1305 message authentication code_. In 2015 12th International Conference on Information Technology - New Generations, pages 145–150. IEEE, April
2015. 10.1109/ITNG.2015.28.

I have an AArch64 implementation almost ready, but it is complicated.

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PR Review Comment: https://git.openjdk.org/jdk/pull/16417#discussion_r1389729727