Re: [Xen-devel] [PATCH v8 02/17] Add cmpxchg16b support for x86-64

["Wu, Feng" <feng.wu@xxxxxxxxx>]

> >>
> >> >>> On 14.10.15 at 11:29, <feng.wu@xxxxxxxxx> wrote:
> >> > I understand your comments above. My understanding about the gcc
> >> > online doc is we don't need to add memory clobber when the variable
> >> > is either an input _or_ output one. However, seems your options is
> >> > memory clobber can be removed only when it is an input _and_ output
> >> > one. It would be highly appreciated if you can correct me if I understand
> >> > the doc incorrectly.
> >>
> >> Yes, I'm pretty convinced you read it wrong: "performs memory
> >> reads or writes to items other than those listed in the input and
> >> output operands" means _any_ operation not expressed by the
> >> ams operands. The two sentence following that actually explain
> >> this in more detail. IOW - unless your operands correctly express
> >> _everything_ the assembly instruction(s) do(es), you need a
> >> clobber (and this is not limited to memory).
> >
> > Thanks for the clarification. So do you think it is better to send only
> > this single patch after fixing the issue in your comments, or wait
> > for the next version of this whole patch set?
> 
> I don't know - I didn't get around to look at the rest of the series yet.

No problem, then I will wait for your comments about other patches in
this series. 

Thanks,
Feng

> 
> Jan


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