On 11/02/2011 11:25 AM, Richard Henderson wrote:
On 11/02/2011 07:18 AM, Andrew MacLeod wrote:
OK, I think i need to revert my position and introduce
__atomic_test_and_set() and __atomic_clear(). bah. I'll work on
that today.
I don't think you do. We already have the __sync functions,
and we should just use those.
actually, that should be sufficinent.
What we need is a preprocessor flag that tells you that you
need to use those older sync routines.
why?
its only for the atomic_flag object that those routines are even used,
so the C++ or C1x implementation of atomic_flag can just use the
existing __sync routines. Since they are defined by the standard as
being required to be lock free, I dont need to worry about them in the
library which is what I was thinking.
I'd just change store and exchange to not try to use those patterns, and
then use the sync patterns in implementing atomic_flag. They would be
documented as required for that functionality.
that should work shouldnt it?
Andrew
