[v3] atomics

[Lawrence Crowl]

On 4/18/08, David Daney <ddaney@avtrex.com> wrote:
> David Daney wrote:
>
> > Jakub Jelinek wrote:
> >
> > > On Fri, Apr 18, 2008 at 10:51:33AM -0700, David Daney wrote:
> > >
> > > > At this point I don't really have an opinion as to how to fix the
> problem.  One thought that comes to mind is to change the definition of
> atomic_flag so that the size of the atomic variable is appropriate for the
> target architecture (32 bits in the case of MIPS)
> > > >
> > >
> > > Best is to add support for the 8 and 16-bit sync builtins.
> > > See e.g. sparc or s390 backends how it can be done using 32-bit
> > > compare and swap instruction.
> > >
> > >
> >
> > Thanks Jakub,
> >
> > Would it make sense to handle this in a more generic manner where the
> operations are expanded?
> >
>
>  Well, that's not likely to work...
>
>
> > Or should each target just write patterns for 8 and 16 bit operations if
> they don't natively support it?
> >
>
>  I will do this for MIPS.

The intent was that either implementations expand the size of the atomics
to the minimum supported size or implement the operation with a
compare-and-swap on the word containing the atomic.

-- 
Lawrence Crowl