[master] RFR: Load narrowKlass from header, AArch64 assembler implementation [v2]

[Andrew Haley]

On Thu, 27 Jan 2022 15:31:46 GMT, Roman Kennke <rkennke at openjdk.org> wrote:

>> src/hotspot/cpu/aarch64/macroAssembler_aarch64.cpp line 3718:
>> 
>>> 3716:   eor(tmp, tmp, markWord::unlocked_value);
>>> 3717:   tst(tmp, markWord::lock_mask_in_place);
>>> 3718:   br(Assembler::NE, slow);
>> 
>> Suggestion:
>> 
>>   tbnz(tmp, exact_log2(markWord::lock_mask_in_place), slow);
>
> Would that work, though? I need to test if the lowest *two* bits are zero (or, together with the preceding eor, test if the lowest two bits are exactly 01). TBNZ only tests a single bit, afaik.

Oh, sorry. Right you are.

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PR: https://git.openjdk.java.net/lilliput/pull/36