J3/05-115r1

Date:    31 Jan 2005
To:      J3
From:    John Reid
Subject: REM(inf,y), REM(x,0.0)

Here is a draft response for F03/0036, with thanks to Malcolm Cohen
for his help.

NUMBER:  F03/0036
TITLE:  IEEE_REM()
KEYWORDS: IEEE-754, remainder()
DEFECT TYPE: Interpretation
STATUS: For consideration

QUESTION:

What is REM(infinity,Y)?  REM(X,0.0)?

What is REM(X,Y) if X and/or Y is NaN?

IEEE-754 requires (in 7.1) both REM(infinity,Y) and REM(X,0.0)
shall be a NaN and raise invalid.

REM(X,Y) when both X and Y are NaN shall be a NaN, and should be
one of NaN arguments.

REM(X,Y) when one of X and Y is a NaN shall be a NaN, and should
the NaN argument.

ANSWER:

The first paragraph of 14.8 states "Complete conformance with the
is not required, but ... the IEEE operation rem shall be provided by
the function IEEE_REM."

The behaviour of IEEE_REM for the cases cited here is as defined
for REM by the IEEE International Standard.

EDITS: None.

SUBMITTED BY: Fred Tydeman

HISTORY: J3/05-115  m171 Submitted