J3/05-110

Date:    4 Jan 2005
To:      J3
From:    Fred Tydeman
Subject: 0.0/0.0, inf/inf, inf-inf, 0.0*inf

NUMBER:  F03/0031
TITLE:  IEEE invalid
KEYWORDS: IEEE-754, invalid exception
DEFECT TYPE: ???
STATUS: For consideration

QUESTION:

What exceptions (if any) are raised by the following:
 infinity + (-infinity)
 infinity - infinity
 0.0 * infinity
 infinity / infinity
 0.0 / 0.0

DISCUSSION:

Fortran 2003 is silent on these expressions.
IEEE-754 defines (in 7.1) those as invalid.

ANSWER:

EDITS:

All edits refer to 04-007.pdf.

[365:??] Add ....
 infinity + (-infinity)
 infinity - infinity
 0.0 * infinity
 infinity / infinity
 0.0 / 0.0

SUBMITTED BY: Fred Tydeman

HISTORY: J3/05-110  m171 Submitted