RFR: 8319716: RISC-V: Add SHA-2 [v8]

[Robbin Ehn]

On Fri, 22 Dec 2023 05:10:11 GMT, Fei Yang <fyang at openjdk.org> wrote:

>> Robbin Ehn has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   index store state back
>
> src/hotspot/cpu/riscv/stubGenerator_riscv.cpp line 3942:
> 
>> 3940: 
>> 3941:       // Step-over a,b, so we are pointing to c.
>> 3942:       // const_add is equal to 4x state variable, div by 2 is thus 2, a,b
> 
> I don't quite understand this code comment.

State is: `{a,b,c,d,e,f,g,h}`
The index used assumes the pointer is at 'c'.
As we know const_add is equal to the size of 4 state variables, if we divide it by 2 we have the size of two state variables.

If that make sense, can you suggest a comment change?

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PR Review Comment: https://git.openjdk.org/jdk/pull/16562#discussion_r1434785945