RFR: JDK-8216437 : PPC64: Add intrinsic for GHASH algorithm [v6]

[Amit Kumar]

On Thu, 9 Jan 2025 09:07:21 GMT, Suchismith Roy <sroy at openjdk.org> wrote:

>> JBS Issue : [JDK-8216437](https://bugs.openjdk.org/browse/JDK-8216437)
>> 
>> Currently acceleration code for GHASH is missing for PPC64. 
>> 
>> The current implementation utlilises SIMD instructions on Power and uses Karatsuba multiplication for obtaining the final result.
>
> Suchismith Roy has updated the pull request incrementally with one additional commit since the last revision:
> 
>   restore

src/hotspot/cpu/ppc/stubGenerator_ppc.cpp line 640:

> 638: //      subkeyH:    R4_ARG2
> 639: //      data: R5_ARG3
> 640: //      blocks: R6_ARG4

How about aligning the comments like this: 

Suggestion:

// Generate stub for GHASH process blocks.
//
// Arguments for generated stub:
//      state:    R3_ARG1 (long[] state)
//      subkeyH:  R4_ARG2 (long[] subH)
//      data:     R5_ARG3 (byte[] data)
//      blocks:   R6_ARG4 (number of 16-byte blocks to process)

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PR Review Comment: https://git.openjdk.org/jdk/pull/20235#discussion_r1909156084