Re: [patch 5/6] lightweight robust futexes: i386

[Chuck Ebbert]

In-Reply-To: <a36005b50602210838wa87764eof7b5d6e5a8a5ab3a@xxxxxxxxxxxxxx>

On Tue, 21 Feb 2006 at 08:38:04 -0800, Ulrich Drepper wrote:
> On 2/21/06, Chuck Ebbert <76306.1226@xxxxxxxxxxxxxx> wrote:
> > > +             : "=a" (oldval), "=m" (*uaddr)
> >                                  ^^^^
> >    Should be "+m" because it's both read and written.
> 
> No, this is why there is the "0" input parameter.

 But this is arg 1, not 0. With a memory clobber it's irrelevant
anyway though.

> > > +             : "memory"
> >                   ^^^^^^^^
> >    Is this necessary? Every possible memory location that could be
> > affected has been listed in the operands if the above change is made.
>
> This makes the asm a barrier for the compiler.

 A comment to that effect would be nice; IOW document the reason for it.

-- 
Chuck
"Equations are the Devil's sentences."  --Stephen Colbert

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