Date: Wed, 22 Mar 2000 10:25:22 +0200 (IST)
From: Eli Zaretskii <eliz AT is DOT elta DOT co DOT il>
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To: Hans-Bernhard Broeker <broeker AT physik DOT rwth-aachen DOT de>
cc: djgpp-workers AT delorie DOT com
Subject: Re: Unnormals???
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On Mon, 20 Mar 2000, Hans-Bernhard Broeker wrote:

> > "Intel Architecture Software Developer's Manual", v.1 "Basic 
> > Architecture" (I downloaded it from their site as 24319002.pdf, but that 
> > was quite a while ago), Section 7.6, Table 7-18.  The Result column only 
> > mentions a real indefinite if neither of the operands is a NaN.  Your 
> > case appears to be covered by the third possible combination (two QNaNs), 
> > whose result should be a QNaN, i.e. either with the sign bit reset or 
> > with a mantissa that doesn't fit the real indefinite description.
> 
> It's not just 'a QNaN'. You get 'the QNaN with the bigger significand'
> (i.e. mantissa), according to my book.

Yes, but in this case the mantissas were identical.

> Thinking about, this seems to imply
> that the sign bit of the QNaN with the (absolutely) bigger significand is
> just copied as-is.

How do you deduce that?  The manual keeps suspicious silence about the 
sign bit.