RFR: 8339698: x86 andw/orw/xorw encoding missing 0x66 prefix

Mon Sep 9 17:56:09 UTC 2024

On Sat, 7 Sep 2024 17:26:45 GMT, Vladimir Kozlov <kvn at openjdk.org> wrote:

>> x86 andw/orw/xorw encoding is missing 0x66 prefix. This bug was discovered as part of the x86 instruction encoding test generation tool and gtest ([JDK-8339507](https://bugs.openjdk.org/browse/JDK-8339507)). This fix is a precursor to the PR for JDK-8339507 (https://github.com/openjdk/jdk/pull/20857).
>> 
>> Best Regards,
>> Sandhya
>
> Good.

> I am ok either way, removing these instructions or fixing the encoding. @vnkozlov Please let me know your thoughts.

Remove them. Check `addw(Register dst, Register src)` - I think it is not used too.

All these instructions were added for first JEP 8223347: Integration of Vector API (Incubator)
May be there were experiments with using them during development.

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PR Comment: https://git.openjdk.org/jdk/pull/20901#issuecomment-2338730973