RFR: 8339113: AccessFlags can be u2 in metadata [v2]

[Martin Doerr]

On Thu, 19 Dec 2024 20:27:28 GMT, Coleen Phillimore <coleenp at openjdk.org> wrote:

>> src/hotspot/cpu/ppc/interp_masm_ppc_64.cpp line 691:
>> 
>>> 689: 
>>> 690:     // Skip if we don't have to unlock. (???is this right???)
>>> 691:     rldicl_(R0, Raccess_flags, 64-JVM_ACC_SYNCHRONIZED_BIT, 63); // Extract bit and compare to 0.
>> 
>> Using `testbitdi` might make it more readable to non-experts.  It took me a while reading aix docs to realize that this platform numbers LSB as 63 and MSB/sign as 0.
>
> yes I like testbitdi better.  I found a sample in the templateInterpreterGenerator code.

Right, Bit 0 refers to the MSB on IBM platforms (not only AIX). Using `testbitdi` is also fine.

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PR Review Comment: https://git.openjdk.org/jdk/pull/22246#discussion_r1897419817