Document: WG14 N1430

negate

Submitter: Fred J. Tydeman (USA)
Submission Date: 2009-12-01
Subject: negate

Background: IEEE-754-1985 suggests and IEEE-754-2008 requires negate(NaN) to affect just the sign bit.

Change existing F.3

-- The unary minus (-) operator provides the minus (-) operation recommended in the Appendix to IEC 60559.

to

-- The unary minus (-) operator provides the negate (-) operation recommended in the Appendix to IEC 60559. It only affects the sign bit. It reverses the sign bit, including for zeros and NaNs.

Add to Raionale:

In IEEE-754, negate is considered a sign bit operation that affects only the sign bit.