[Python-Dev] Signalling NANs

Steven D'Aprano steve at pearwood.info
Sun Nov 11 16:50:23 EST 2018

On Sat, Nov 10, 2018 at 04:27:29PM -0800, Nathaniel Smith wrote:

> Apparently loading a sNaN into an x87 register silently converts it to
> a qNaN, and on Linux C compilers are allowed to do that at any point:
>    https://stackoverflow.com/questions/22816095/signalling-nan-was-corrupted-when-returning-from-x86-function-flds-fstps-of-x87

Thanks for finding that.

> So the Debian/RH difference may just be different register allocation
> in two slightly different compiler versions.

The Debian box uses an ARM processor, so there's that difference too.


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