Re: [OpenRISC] [PATCH v3 08/25] openrisc: add cmpxchg and xchg implementations

[Richard Henderson]

On 02/23/2017 01:20 AM, Stafford Horne wrote:
> On Wed, Feb 22, 2017 at 12:19:40PM +0100, Peter Zijlstra wrote:
> > On Wed, Feb 22, 2017 at 04:11:37AM +0900, Stafford Horne wrote:
> > > +	__asm__ __volatile__(
> > > +		"1:	l.lwa %0, 0(%1)		\n"
> > > +		"	l.sfeq %0, %2		\n"
> > > +		"	l.bnf 1f		\n"
> > > +		"	 l.nop			\n"
> > > +		"	l.swa 0(%1), %3		\n"
> > > +		"	l.bnf 1b		\n"
> > > +		"1:	 l.nop			\n"
> > > +		: "=&r"(old)
> > > +		: "r"(ptr), "r"(old), "r"(new)
> > > +		: "cc", "memory");
> >
> > I just noticed this, but having both labels have the same name is
> > somewhat confusing.
>
> Right, better to use '2' for the second one.

Better still to put the second label after the delay-slot nop.
You don't need to execute that on the way out.


r~