[jmm-dev] bitwise RMW operators, specifically testAndSetBit/BTS

Martin Buchholz martinrb at google.com
Fri Jul 22 20:29:58 UTC 2016

On Wed, Jul 20, 2016 at 10:16 PM, David Holmes <david.holmes at oracle.com>

> On 21/07/2016 4:20 AM, Hans Boehm wrote:
>> You are not alone.  I have the suspicion that "word tearing" used to mean
>> 17.7 before the 2005 JLS revision.  But the JLS usage seems to have won,
>> for better or worse, at least in Java circles.
> No not at all. word-tearing has "always" concerned the inability to
> perform sub-word atomic accesses - ie the subword has to be torn out of the
> word.
> Here's a 2001 reference which was part of the discussion that led to the
> JLS update :)
> http://www.cs.umd.edu/~pugh/java/memoryModel/archive/0967.html

Thanks for the history lesson.  "word tearing" still seems unintuitive to
me - it's the INability to tear up a word into sub-words that's the
problem.  That is, "word tearing" is not the problem, it's the solution we
can't use!  But my own "word bleeding" is also not that great, and unlikely
to catch on.

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