> On 19 Jun 2015, at 09:31, Paolo Bonzini <pbonz...@redhat.com> wrote:
>
>
>
> On 19/06/2015 09:29, Mark Burton wrote:
>> Does anybody know if the current atomic_cmpxchg will support 64 bit
>> on a (normal) 32 bit x86, or do we need to special case that with
>> cmpxchg8b ? (I get the impression that it will automatically use
>> cmpxchg8b, but not cmpxchg16b - but I’m by no means sure).
>
> Both cmpxchg8b and cmpxchg16b are used, respectively on 32-bit and
> 64-bit x86.
>
Thanks Paolo, so we are OK for x86, but we would need to disable multi-thread
for other 32 bit hosts, and provide a correct implementation for non
multi-thread…
You dont happen to know of a convenient macro we can use to test for ’32 bit
hosts that dont support 64bit cmpxchg ….’
Cheers
Mark.
> Paolo
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mark.burton
