RFR: 8256431: [PPC64] Implement Base64 encodeBlock() for Power64-LE [v4]

Tue Dec 15 20:26:04 UTC 2020

On Tue, 15 Dec 2020 20:02:31 GMT, Corey Ashford <github.com+51754783+CoreyAshford at openjdk.org> wrote:

>> It'd be possible to put them into a struct and have the offsets computed by the C++ compiler, but I'm fine with your version. I guess there won't be many manual changes any more.
>> I'll test the code a bit longer, but it looks good so far.
>
> Oh, that's a great idea!  I'm willing to make that change, if you don't mind one last cycle of review.

It's your choice. I'm also fine with your current version.
Btw. I had also thought a bit about the division by constants. It's only used outside the loop. Otherwise I'd have suggested to use mulhd (e.g. positive long can get divided by 3 by mulhd with 0x5555555555555556, division by 12 by mulhd with 0x2aaaaaaaaaaaaaab + right shift by one). Such fast code gets generated by C2 compiler.

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PR: https://git.openjdk.java.net/jdk/pull/1245