Re: [boost] [atomic] Support for specialized instructions

Subject: Re: [boost] [atomic] Support for specialized instructions
From: Andrey Semashev (andrey.semashev_at_[hidden])
Date: 2013-11-23 10:08:37

On Saturday 23 November 2013 12:37:43 tim wrote:
> 
> >> bts/btr may be
> >> useful, but i suppose they are rather specific to x86? i wonder, how
> >> would they map to arm?
> > 
> > AFAIK, ARM implements atomic ops with LL/SC instructions, so it should
> > be flexible enough to implement it. I'm not very familiar with the
> > architecture though.
> 
> true ... though i'm not sure how well it performs: it emulates cas with
> ll/sc and atomic ops with cas ... but true, this is another issue and
> one of the reasons why i always suggest to use std::atomic if possible ...

Yes, that's worth fixing too. PowerPC also implements LL/SC model and it has 
the complete implementation in Boost.Atomic. We'll need to do the same for 
ARM.