Single byte Atomic::cmpxchg implementation

[David Holmes]

On 11/09/2014 6:22 PM, Andrew Haley wrote:
> On 08/09/14 03:11, David Holmes wrote:
>> Note there is currently no ARM code in the OpenJDK itself. Of course the
>> Aarch64 project will hopefully be changing that soon, but I would not
>> think they need the logic you describe below.
>
>  From the AArch64 project's point of view, all we need is for the
> single byte Atomic::cmpxchg implementation to be move into os_cpu/
> and we can do the rest.
>
> The question in my mind is the extent to which we need to maintain
> compatibility with old C++ compilers.  Modern ones have all the
> primitives we need as builtins, and will often generate better code
> than with inline assembler.

For things like Atomic::*  the definitions are in platform specific 
files so you should be able to use whatever mechanism you want and 
require whatever minimal compiler version is needed.

David

> Andrew.
>