Re: [GD-General] ieee754 -0.0f?

[Brian H. <ho...@bo...>]

On Wed, 01 Feb 2006 09:50:00 -0700, Andras Balogh wrote:
> I know that -0.0f =3D=3D +0.0f is true, but the floating point
> representation of the two numbers should be different, no?

They are different, on an IEEE compliant system.  IEEE-754 has the 
high bit reserved for sign, such that on a 32-bit system you would 
have:

-0.0 =3D 0xbf800000
+0.0 =3D 0x3f800000

> Shouldn't the negative zero have the sign bit set? Well, on my
> machine -0.0 and 0.0 are bitwise equal!! What's going on here?

You didn't mention the language or how you're generating those values.  
Using VC6 on a Pentium-M by setting global floats I get the correct 
and expected values.

Brian