Re: [boost] Notice: Boost.Atomic (atomic operations library)

Subject: Re: [boost] Notice: Boost.Atomic (atomic operations library)
From: Helge Bahmann (hcb_at_[hidden])
Date: 2009-12-03 16:19:46

Hi Phil,

Am Thursday 03 December 2009 15:58:03 schrieb Phil Endecott:
> Helge Bahmann wrote:
> > I will shortly be adding a small howto on adding platform support to the
> > library.
>
> Please let me know when this is ready.  I currently have a bit of time
> to spend on this.

There is one planned internal API change (switching to the four-parameter 
compare_exchange_*) still pending, but that should be straight-forward 
afterwards. If you want to try, I have started writing things up, the current 
state is at:

http://www.chaoticmind.net/~hcb/projects/boost.atomic/doc/architecture_support.html

(the tarball also contains the generated docs, still busy reworking to use 
boostdoc)

> In summary, the cases that I need to handle are:
>
> 1. Linux kernel provided memory-barrier and CAS operations (only);

does any of these arm platforms (this is pre-v6 probably?) actually support 
smp? if not, then the barriers will probably be NOPs

> 2. Asm load-locked/store-conditional for words (only);
> 3. As 2 but also for smaller types.

sounds like this is going to be one of the most complicated platforms, so I 
really appreciate your experience here... 

> I could probably work this out from the source, but it would save some
> time to have some hints....

It's probably still required to delve into the source, but I hope that the 
write-up provides a good entry point (but of course don't hesitate on 
commenting, there is lots of things to improve).

Best regards
Helge