J3/05-111
Date: 4 Jan 2005
To: J3
From: Fred Tydeman
Subject: Signbit of NaN
NUMBER: F03/0032
TITLE: Sign bit of IEEE NaN
KEYWORDS: IEEE-754, NaN, sign bit, negative
DEFECT TYPE: Contradiction ???
STATUS: For consideration
QUESTION:
Do IEEE-754 NaNs have a sign bit? Can they be negative? Does a
sign bit imply a value can be either positive or negative?
DISCUSSION:
Fortran 2003 in 14.10.2 (IEEE_COPY_SIGN) says that NaNs have a
sign bit. But, 14.10.10 (IEEE_IS_NEGATIVE) says NaNs are not
negative. This appears to be a contradiction between two parts
of Fortran 2003.
ANSWER:
EDITS:
All edits refer to 04-007.pdf.
SUBMITTED BY: Fred Tydeman
HISTORY: J3/05-111 m171 Submitted