This is the mail archive of the gcc@gcc.gnu.org mailing list for the GCC project.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

Re: Bug related to floating-point traps?


On 2005-06-15 15:45:34 +0200, Gabriel Paubert wrote:
> The exception flags are sticky. So you get the exception because
> operations before feenableexcept set the overflow flag.

I know that the flags are sticky. But I thought the traps were linked
to the FP operations only (not to the flags).

> The  difference is that the PPC triggers the exception as soon
> as you unmask the exception while the x86 only checks for
> pending exceptions at the beginning of an arithmetic FP instruction. 

OK, the PPC behavior seems to be more logical to me.

[...]
> On x86, SSE exception handling is much saner.

and the rounding precision too. :)

Thanks for the explanations.

-- 
Vincent Lefèvre <vincent@vinc17.org> - Web: <http://www.vinc17.org/>
100% accessible validated (X)HTML - Blog: <http://www.vinc17.org/blog/>
Work: CR INRIA - computer arithmetic / SPACES project at LORIA


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]