Re: [Qemu-devel] [PATCH] Fix NaN handling in softfloat

[Thiemo Seufer]

Daniel Jacobowitz wrote:
> On Thu, Nov 08, 2007 at 12:05:25AM +0100, Aurelien Jarno wrote:
> > Has Thiemo already said, there is no IEEE behavior. If you look at the
> > IEEE 754 document you will see that it has requirements on what should
> > be supported by an IEEE compliant FPU, but has very few requirements on
> > the implementation.
> 
> If folks don't like the target conditionals there, I recommend we just
> set some low bit to be sure it's a NaN and move on.

I disagree. I chose on purpose the format recommended in the MIPS
architecture specification. The general format seems to be commonly
preferred beyond the MIPS world.

> The softfloat
> implementation is not all that close to matching any one hardware FPU.

At least for MIPS I expect it to be close enough to real hardware.


Thiemo