Subject: Re: [boost] [atomic] Availability detection
From: Andrey Semashev (andrey.semashev_at_[hidden])
Date: 2010-01-31 08:13:12
On 01/31/2010 03:22 PM, Helge Bahmann wrote:
> (you mean cmpxchg8b probably)
Right.
> Because the compiler cannot always know if you
> might intend to run the code on a 486 unless you explicitly tell it?
>
> FWIW if you pass -march=i686 to gcc then the compiler will unconditionally
> generate code that cannot run on 486 (cmov& friends), Boost.Atomic will
> detect that case as well and also unconditionally generate cmpxchg8b. If you
> do *not* pass this flag, the decision whether to use cmpxchg8b can only be
> made at runtime.
Ok, this behavior is fine with me. Thanks, and looking forward for your
library in Boost!