Re: [boost] [atomic] unconditional cmpxchg8b support

Subject: Re: [boost] [atomic] unconditional cmpxchg8b support
From: Tim Blechmann (tim_at_[hidden])
Date: 2012-10-23 07:46:42

>> using boost.atomic on ia32/gcc causes me quite some headaches these
>> days, as the cmpxchg8b instruction is enabled via the __i686__ or
>> __x86_64__ macros.
>> however on debian for example, the compiler defaults to generate code
>> for i486. cmpxchg8b has been introduced with the p5 architecture,
>> though, so compiling without specifying a -march flag won't generate the
>> instruction.
> 
> GCC will not let you use instructions outside of the target architecture.

fyi, boost.atomic is using inline assembly