Subj : Re: Memory visibility and MS Interlocked instructions
To   : comp.programming.threads
From : Sean Kelly
Date : Thu Sep 01 2005 10:49 am

Alexander Terekhov wrote:
> Sean Kelly wrote:
> [...]
> >                                                            msync.acq
> > and msync.rel operations (to use atomic<> semantics) would both need
> > the LOCK prefix.  Is this correct?
>
> No.
>
> >                                    I'll admit that until this I was
> > beginning to think that only msync.acq stores needed a LOCK.
>
> That's not true either.

Help me out here :)  It's been established that loads can be migrated
above preceding stores if no membars are present, so LOCK must be used
in some cases to prevent this, correct?  Please note that I'm
considering IA-32 here, not IA-64's emulation of IA-32 behavior.


Sean

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