Re: __sync_lock_test_and_set on ARM

["Phil Endecott" <spam_from_gcc_help_2 at chezphil dot org>]

Andrew Haley wrote:
> Phil Endecott writes:
>  > Andrew Haley wrote:
>  > > David Daney writes:
>  > >  > There is nothing that says that __sync_compar_and_swap() cannot expand 
>  > >  > to a libcall.
>  > >
>  > > Err, if a port doen't have an implementation, that's what gcc does
>  > > anyway.  :-)
>  > 
>  > That's what the docs say, but actually if you try to use __sync_* on 
>  > ARM you'll get a linker error.  A library implementation would need to 
>  > be OS-specific.
>
> Well, yes.  What else would you expect?  I don't understand your
> point.

OK, there's a (subtle) difference between "expands to a library call" 
and "expands to a library call which is actually implemented in libgcc".

"My point", now about a thousand messages ago (:-!), is that I'd quite 
like for __sync_lock_test_and_set to expand to a SWP instruction 
please; and that's all.


Phil.