Re: [PATCH 2/2] powerpc: cleanup hw_irq.h

[Christophe Leroy]

Le 27/08/2019 Ã 19:29, Segher Boessenkool a ÃcritÂ:
> On Tue, Aug 27, 2019 at 10:48:24PM +1000, Nicholas Piggin wrote:
> > Christophe Leroy's on August 27, 2019 6:13 pm:
> > > +#define wrtee(val)	asm volatile("wrtee %0" : : "r" (val) : "memory")
> > > +#define wrteei(val)	asm volatile("wrteei %0" : : "i" (val) : "memory")
> >
> > Can you implement just one macro that uses __builtin_constant_p to
> > select between the imm and reg versions? I forgot if there's some
> > corner cases that prevent that working with inline asm i constraints.
>
> static inline void wrtee(long val)
> {
> 	asm volatile("wrtee%I0 %0" : : "n"(val) : "memory");
> }

Great, didn't know that possibility.

Can it be used with any insn, for instance with add/addi ?
Or with mr/li ?

> (This output modifier goes back to the dark ages, some 2.4 or something).

Hope Clang support it ...

Christophe

> Segher