RFR: 8316592: RISC-V: implement poly1305 intrinsic [v3]

[null]

On Wed, 1 Nov 2023 15:47:04 GMT, Hamlin Li <mli at openjdk.org> wrote:

>> src/hotspot/cpu/riscv/stubGenerator_riscv.cpp line 4424:
>> 
>>> 4422:   void pack_26(Register dest0, Register dest1, Register dest2, Register src) {
>>> 4423:     const Register t3 = x28;
>>> 4424:     const Register t4 = x29;
>> 
>> Hardcoding is not nice here. Maybe add two extra formal parameters like `tmp1` and `tmp2` for this function? We could ask for two usable registers (with *++regs) in the caller and pass them to this function.
>
> Seems the tmpx in generate_poly1305_processBlocks do not carry state for long time, maybe t1/t2 or t2 can be used here.
> And as Fei indicated, better to passed in register by parameters.

Added parameters for `pack_26` function.

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PR Review Comment: https://git.openjdk.org/jdk/pull/16417#discussion_r1379178295