Date: Mon, 20 Mar 2000 18:31:59 +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:

> > Not only because of this, but also because how Intel treats the real 
> > indefinite.  It is clear (to me) from that treatment that they use the 
> > sign bit as a flag, to the effect that this NaN was produced by an 
> > operation wher none of the operands was a NaN.
> 
> The sign bit alone does not identify the 'real indefinite'. The mantissa
> is also fixed. So the 'flag', if any, would be the whole 64 bits of
> information, not just the sign bit.

Not really: if you flip the sign but leave the rest alone, the real 
indefinite becomes a QNaN; you don't need to change the rest of the
bits.