RFR: 8319716: RISC-V: Add SHA-2

[Robbin Ehn]

On Wed, 8 Nov 2023 14:47:07 GMT, Robbin Ehn <rehn at openjdk.org> wrote:

> Hi, please consider.
> 
> Main author is @luhenry, I only fixed some minor things and tested it.
> 
> Such as:
> test/hotspot/jtreg/compiler/intrinsics/sha/
> test/jdk/java/security/MessageDigest/
> test/jdk/jdk/security/
> tier1
> 
> And still running some test.

AFIACT the are pretty much the same, except for constants handling in 256.
Openssl preloads the constants into V10->V25 for 256.
I think that is beneficial for multi block, but not for single pass.

Compare these 512 round 2s:

    __ vl1re64_v(v15, consts);     |    @{[vle64_v $V20, ($KT)]}
    __ addi(consts, consts, 32);   |    addi $KT, $KT, 32
    __ vadd_vv(v14, v15, v12);     |    @{[vadd_vv $V18, $V20, $V14]}
    __ vsha2cl_vv(v17, v16, v14);  |    @{[vsha2cl_vv $V24, $V22, $V18]}
    __ vsha2ch_vv(v16, v17, v14);  |    @{[vsha2ch_vv $V22, $V24, $V18]}
    __ vmerge_vvm(v14, v10, v13);  |    @{[vmerge_vvm $V18, $V10, $V16, $V0]}
    __ vsha2ms_vv(v12, v14, v11);  |    @{[vsha2ms_vv $V14, $V18, $V12]}


I suggest we create a new enhancement for preload constants in 256 multi-block and ship this.

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PR Comment: https://git.openjdk.org/jdk/pull/16562#issuecomment-1803627957