RFR: JDK-8216437 : PPC64: Add intrinsic for GHASH algorithm [v28]

[Suchismith Roy]

On Tue, 18 Mar 2025 09:08:34 GMT, Suchismith Roy <sroy at openjdk.org> wrote:

>> I still find it hard to read. Can you describe the algorithm in pseudo code or mathematical equations? We can try to map it to a shorter instruction sequence.
>> Btw. the comment looks wrong here: vxor(vLowProduct, vLowProduct, vReducedLow); // Reduction using constant
>
> @TheRealMDoerr  
> https://www.researchgate.net/publication/285612706_Implementing_GCM_on_ARMv8
> 
> I think the same algorithm used for polynomial reduction -Section 4.3

Hi @theRealAph Do you see a scope to reduce these swaps in the algorithm , for the above mentioned instructions. 
I feel there is a similar set of instructions used to perform reduction in 
https://www.researchgate.net/publication/285612706_Implementing_GCM_on_ARMv8

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PR Review Comment: https://git.openjdk.org/jdk/pull/20235#discussion_r2002800508