RFR: 8338814: [PPC64] Unify interface of cmpxchg for different types

Fri Aug 23 10:02:34 UTC 2024

PPC64 code has very complicated cmpxchg functions in MacroAssembler. We should have at least a unified argument list for the different types and the features should be usable with all types.
I have also cleaned up the `RegisterOrConstant` functions because they are used by the cmpxchg code.

One difference in the argument list still exists: `cmpxchgb` and `cmpxchgh` use extra temp registers to support older processors. They should get removed with [JDK-8331859](https://bugs.openjdk.org/browse/JDK-8331859).

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Commit messages:
 - 8338814: [PPC64] Unify interface of cmpxchg for different types

Changes: https://git.openjdk.org/jdk/pull/20689/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=20689&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8338814
  Stats: 123 lines in 9 files changed: 38 ins; 3 del; 82 mod
  Patch: https://git.openjdk.org/jdk/pull/20689.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/20689/head:pull/20689

PR: https://git.openjdk.org/jdk/pull/20689