Date:	Wed, 15 Mar 2000 19:12:28 +0200 (IST)
From:	Eli Zaretskii <eliz AT is DOT elta DOT co DOT il>
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To:	Dieter Buerssner <buers AT gmx DOT de>
cc:	djgpp-workers AT delorie DOT com
Subject:	Re: Unnormals???
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On Wed, 15 Mar 2000, Dieter Buerssner wrote:

> So there will be 
> bitpatterns, with a finite exponent and a non set msb in the 
> mantissa. We called those unnormal in this threat. They could in 
> principle be renormalized (when the mantissa is not zero). But I 
> think, they are just invalid.

Yes, these numbers are invalid.  They cannot result from any FP 
operation, only from passing arbitrary buffers to functions or casting 
such buffers to long double.

> They are not numbers so we could call them NaNs.

I don't think this is a good idea, because, unlike NaNs, unnormals 
*always* mean there's a bug lurking somewhere.  So it makes sense to tell 
the user explicitly about this.  If we print NaN, the user cannot know 
whether this is the normal IEEE NaN with its distinct bit pattern or 
something else.

> Perhaps there is a reader of this list, who has access to IEEE
> floating point standards, and can check whether it allows an 
> unnormalized mantissa with finite exponent for the extended
> IEEE type.

Note that C9X and IEEE are two different standards which don't 
necessarily coincide.

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