Re: [PATCH] local_t : powerpc extension - use long for powerpc32

[Kumar Gala <galak@kernel.crashing.org>]

On Feb 15, 2007, at 3:23 PM, Mathieu Desnoyers wrote:

> * Kumar Gala (galak@kernel.crashing.org) wrote:
> > On Feb 15, 2007, at 2:02 PM, Mathieu Desnoyers wrote:
> >
> > > * Kumar Gala (galak@kernel.crashing.org) wrote:
> > > > is there a reason this isn't local_add_return(long a, local_t  
> > > > *l) on
> > > > ppc32?
> > > >
> > > > (same comment for other functions)
> > > >
> > > > - k
> > >
> > > no, except that we use the code is taken from atomic.h and used an
> > > int parameter. However, due to the semantics of local_t, we should
> > > manipulate longs instead of ints, even if they are the same size  
> > > on a
> > > given architecture (ppc32 and mips32 are affectec by this).
> > >
> > > Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
> >
> > Right, this means we can simply for ppc version down to:
> >
> > +static __inline__ int local_add_return(int a, local_t *l)
> > +{
> > +	int t;
> > +
> > +	__asm__ __volatile__(
> > +"1:	PPC_LLARX	%0,0,%2		# local_add_return\n\
> > +	add	%0,%1,%0\n"
> > +	PPC405_ERR77(0,%2)
> > +"	PPC_STLCX	%0,0,%2 \n\
> what about the dot after stwcx ? (stwcx.) ? Is it no longer required ?

Its implied, PPC_LLARX and PPC_STLCW are #defines that expand to  
proper instructions.

(look in include/asm-powerpc/asm-compat.h) for the defines.

Also, the PPC405_ERR77 will preprocess out on ppc64 if you were  
concerned.

- k
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