On 2013-05-16, at 6:16 PM, Mike Duigou <mike.dui...@oracle.com> wrote:

>> Note that the instruction also works on 32-bit, and once the builds all use 
>> sufficiently modern compilers, the same source code works for both.
> 
> Understood, but it's only going to be available on processors that support 
> also support EMT64, correct? I am not sure what the best way to characterize 
> the required architecture should be.

According to the Intel docs, it has to provide CLMUL and AVX features, so 
that's what the code looks for.  CLMUL gets you CLMUL, AVX adds the 
three-operand form that gets you the better code and keeps the guy writing the 
code from going even more nuts than he already did, because there is no way I 
want to have 4 versions of that assembly language, never mind that there's not 
too many chips in the CLMUL-minus-AVX category anyway.

David

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