> >Modified Files:
> > src/sys/arch/sparc/dev: if_ie_obio.c kd.c tctrl.c ts102.c
> > src/sys/arch/sparc/include: pmap.h
> > src/sys/arch/sparc/sparc: cpuvar.h memecc.c timer.c
> >
> >Log Message:
> >- remove unused but set variables.
> >- use __USE() where necessary.
> >- remove useless 'volatile' markers
>
> I am not sure that those volatile markers are useless.
>
> For example:
>
> > #define raise_ipi(cpi,lvl) do { \
> >- volatile int x; \
> >+ int x; \
> > (cpi)->intreg_4m->pi_set = PINTR_SINTRLEV(lvl); \
> >- x = (cpi)->intreg_4m->pi_pend; \
> >+ x = (cpi)->intreg_4m->pi_pend; __USE(x); \
> > } while (0)
>
> I think that the change from the use of volatile to the use of
> __USE() is a change from reliance on the C standard's guarantee
> that the memory location behind (cpi)->intreg_4m->pi_pend really
> will be accessed, to a reliance on what a particular compiler
> happens to do in this situation.
the volatile applies to the access to pi_pend, which is
marked a volatile (via the whole intreg_4m pointer.)
i'm not sure that "volatile int x;" actually means
anything useful. it's pointer accesses that matter.
i could be wrong; volatile is a pretty tricky area.
certainly, the generated code is fine (and in most
cases, identical).
.mrg.
