[PATCH 1/2] Document HLE / RTM intrinsics

Andi Kleen andi@firstfloor.org
Sun Jan 27 21:22:00 GMT 2013


On Sun, Jan 27, 2013 at 07:15:42PM +0100, Florian Weimer wrote:
> On 01/12/2013 04:28 PM, Andi Kleen wrote:
> 
> >The TSX HLE/RTM intrinsics were missing documentation. Add this to the
> >manual.
> 
> Are these intrinsics restricted to free-standing implementations?  Or 
> are these instructions designed in such a way that they work as expected 
> even if the threading library uses them internally?  (That would be 
> quite a feat.)

They can be combined with a threading library, with some restrictions.
See the manual for details. All transactions are flattened.

http://software.intel.com/sites/default/files/m/a/b/3/4/d/41604-319433-012a.pdf
chapter 8

"restrictions" may lead to not eliding or abort, but never to
correctness problems.

Documenting all that is out of scope for the gcc manual though.

-Andi

-- 
ak@linux.intel.com -- Speaking for myself only.



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