Subj : Re: AMD has cmpxchg16b now - sort of
To   : comp.programming.threads
From : Joe Seigh
Date : Tue Mar 08 2005 12:49 pm

On 08 Mar 2005 16:47:19 GMT, Casper H.S. Dik <Casper.Dik@Sun.COM> wrote:

> "Joe Seigh" <jseigh_01@xemaps.com> writes:
>
>> No I meant versioning.  When they add a new architectural feature,
>> it becomes present on every processor of a certain version or later.
>> That way, all you need to know when getting a processor is the version
>> number.
>
> And version X from competeitor A, version Y from B, version Z from C,
> etc.  There are four or five viable x86 CPU producers.  The
> version bits work much better in x86 space because of that.
>

That's all well and fine if the feature is optional and you have a viable
workaround if the feature is not available.   There isn't any workaround
for cmpxchg16b.

Not a problem in the short term since I'm switching to powerpc and keeping
my 32 bit intel system for the time being.   There is no short term need to
have atomic_ptr work on x86-64 so the longer I wait the better.

-- 
Joe Seigh

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