Re: [Qemu-devel] [PATCH 1/6] softfloat: remove HPPA specific code

[Nathan Froyd]

On Thu, Jan 06, 2011 at 03:34:38PM +0000, Peter Maydell wrote:
> Similarly I'm dubious about uses in helper_fsel, helper_fcmpu
> and helper_fcmpo, efsctsi, efsctui, efsctsiz, efsctuiz, efsctsf,
> efsctuf and all the helper_efd* functions. I haven't actually
> checked them all, but for instance efdctsi in the Power ISA
> 2.03 spec says "NaNs are converted as though they were zero",
> but qemu's code says:
>     /* NaN are not treated the same way IEEE 754 does */
>     if (unlikely(float64_is_quiet_nan(u.d)))
>         return 0;
> 
> which is not going to do the right thing for signaling NaNs.

I think you are correct about fsel, fcmpu, and fcmpo.

The E500 FP instructions are broken for various corner cases (and there
are a lot of them, because E500 is screwy).  I've been meaning to go
through and fix them up, but haven't taken the time to do so.

-Nathan