On 19.11.2011 01:22, Walter Bright wrote:
On 11/18/2011 1:32 PM, Paul D. Anderson wrote:
From the Decimal Arithmetic Specification
(http://speleotrove.com/decimal/decarith.pdf):
"All special values may have a sign, as for finite numbers. The sign
of an
infinity is significant (that is, it is possible to have both positive
and
negative infinity), and the sign of a NaN has no meaning, although it
may be
considered part of the diagnostic information."
Having no meaning means it is legitimate to not be concerned if the sign
is toggled.
I'm not sure about that. They may simply be saying that it has no
"physical" meaning, without saying that it has no meaningful semantics.
The behaviour is a bit strange, because x86 does define the sign of NaN
for all operations.
If the sign doesn't have reliable semantics, we probably shouldn't be
printing it. It just causes confusion. Personally, I think it would make
more sense to only print the sign if you're also printing the payload.
Maybe print -nan for %a format, but not for %f and %e.
