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SubjectRe: [tip:locking/core] locking/atomics: Simplify the op definitions in atomic.h some more
On Tue, May 15, 2018 at 06:53:08PM +0100, Mark Rutland wrote:
> On Tue, May 15, 2018 at 07:10:21PM +0200, Peter Zijlstra wrote:
> > On Tue, May 15, 2018 at 04:43:33PM +0100, Mark Rutland wrote:
> > > I *think* the table can encode enough info to generate atomic-long.h,
> > > atomic-instrumented.h, and the atomic.h ordering fallbacks. I'll need to
> > > flesh out the table and check that we don't end up clashing with
> > > some of the regular fallbacks.
> >
> > Yes, details details ;-)
> >
> > > # name meta args...
> > > #
> > > # Where meta contains a string of:
> > > # * B - bool: returns bool, fully ordered
> > > # * V - void: returns void, fully ordered
> >
> > void retuns are relaxed
>
> How about:
>
> V - void: returns void, no ordering variants (implicitly relaxed)

Works for me.

> > > # * I - int: returns base type, all orderings
> > > # * R - return: returns base type, all orderings
> > > # * F - fetch: returns base type, all orderings
> > > # * T - try: returns bool, all orderings
> >
> > Little more verbose than mine, I think we can get there with X and XB
> > instead of I and T, but whatever :-)
>
> Mhmm. I found it easier to do switch-like things this way, but it works
> regardless.

I'm a minimalist, but yeah whatever ;-)

> > > # Where args contains list of type[:name], where type is:
> > > # * v - pointer to atomic base type (atomic or atomic64)
> > > # * i - base type (int or long)
> > > # * I - pointer to base type (int or long)
> > > #
> > > add VRF i v
> > > sub VRF i v
> > > inc VRF v
> > > dec VRF v
> > > or VF i v
> > > and VF i v
> > > andnot VF i v
> > > xor VF i v
> > > xchg I v i
> > > cmpxchg I v i:old i:new
> > > try_cmpxchg T v I:old i:new
> > > add_and_test B i v
> > > sub_and_test B i v
> > > dec_and_test B v
> > > inc_and_test B v

we might also want:

set V v i
set_release V v i
read I v
read_acquire I v

(yes, I did get the set arguments the wrong way around initially)

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