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.
In addition, the specification, based on IEEE 754 and IEEE 854, makes a
distinction between a "signaling NaN" (sNaN) and a "quiet NaN" (qNaN). D
doesn't make this distinction. In essence all D NaNs are signaling.
Signaling vs quiet is not set by the sign bit, but by the most significant bit
of the significand. D does make use of signaling NaNs as they are what are
generated for uninitialized data.
Other than that, the payloads are not used. I did support them in Digital Mars
C, but nobody used them.
