RFR: 8354231: x86: Purge FPU support from (Macro)Assembler after 32-bit x86 removal

[Aleksey Shipilev]

On Thu, 10 Apr 2025 16:30:31 GMT, Vladimir Kozlov <kvn at openjdk.org> wrote:

>> There are lots of cleanups possible in (Macro)Assembler after 32-bit x86 removal. This cleanup is focused on removing the large parts of x87 FPU support that are no longer needed. Note that _some_ math stubs are actually using x87 FPU in a very limited manner, but the implementations use separate definitions (under `LP64`). Those are left alone, and we clean up x86_32 code here.
>> 
>> Additional testing:
>>  - [x] Linux x86_64 server fastdebug, `all`
>
> src/hotspot/cpu/x86/assembler_x86.hpp line 1400:
> 
>> 1398: #ifndef _LP64
>> 1399:   void emms();
>> 1400: 
> 
> So you keeping this 32-bit code for now?

Yeah, I want clean cuts. These are not FPU-related. Once we clear large chunks, leftover removals would be clearer.

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PR Review Comment: https://git.openjdk.org/jdk/pull/24558#discussion_r2037829840