RFR: 8186670: Implement _onSpinWait() intrinsic for AArch64 [v3]

[Evgeny Astigeevich]

On Tue, 21 Sep 2021 14:47:41 GMT, Andrew Haley <aph at openjdk.org> wrote:

>> To have assembly instructions in `-XX:+PrintAssembly` output `hsdis` needs to be provided:
>> 
>>   0x0000ffff61ba2b5c: ;   {metadata({method} {0x0000000800466ab8} 'isLatin1' '()Z' in 'java/lang/String')}
>>   0x0000ffff61ba2b5c: 0857 8dd2 | c808 a0f2 | 0801 c0f2 | e807 00f9
>>  ;; 0xFFFFFFFFFFFFFFFF
>>   0x0000ffff61ba2b6c: 0800 8092 | e803 00f9
>> 
>>   0x0000ffff61ba2b74: ;   {runtime_call counter_overflow Runtime1 stub}
>> 
>> 
>>  However it can help to skip to the place where instructions are expected and to check instructions' hex code.
>
> True. There's no C1 equivalent.

I rewrote a test to parse `XX:+PrintAssembly` hex instructions.

-------------

PR: https://git.openjdk.java.net/jdk/pull/5562