RFR: 8290324: Move atomic operations outside of os_xxx.hpp

[David Holmes]

On Thu, 14 Jul 2022 21:38:58 GMT, Ioi Lam <iklam at openjdk.org> wrote:

> The os_xxx.hpp files inject extra methods/fields that are specific to atomic operations into the `os` class. However, the injected methods/fields are used only by a specific os/cpu combination. Therefore, they should not be inside the `os` class, which should contain only APIs that are used across platforms.
> 
> - For ports where the `atomic_copy64()` function is used in a single file, I moved it as an inline function in that file
> - Otherwise it's moved to `atomic_<os>_<cpu>.hpp`
> - The linux/arm port is a little more involved, but the new code should be a little cleaner than the old code.

Seems okay - good cleanup.

I'm okay with it if Aarch64 folk are.

Thanks.

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Marked as reviewed by dholmes (Reviewer).

PR: https://git.openjdk.org/jdk/pull/9501