To: J3 J3/07-113
From: Van Snyder
Subject: RRSPACING (UTI 092)
Date: 2007 January 22
1 Introduction
UTI 092 argues that RRSPACING(X) should be an IEEE NaN if X is IEEE Inf.
On the other hand, how- ever, RRSPACING(X) can be written as
ABS(FRACTION(X)) * RADIX(X) / EPSILON(X). RADIX and EPSILON are inquiry
functions, so their result values don't depend upon their argument values,
while the result value of FRACTION(X) is defined to be "the same value as
X" if X is an IEEE infinity. I would be really surprised if ABS(Inf ) or
ABS(-Inf ) were not Inf, so RRSPACING(ħInf ) ought to be +Inf.
2 Edits
Edits refer to 07-007. Page and line numbers are displayed in the margin.
Absent other instructions, a page and line number or line number range
implies all of the indicated text is to be replaced by associated text,
while a page and line number followed by + (-) indicates that associated
text is to be inserted after (before) the indicated line. Remarks are
noted in the margin, or appear between [ and ] in the text.
[420:9] ------------------------------------------------------------------
[Editor: "zero" => "an IEEE NaN".]
[420:10+] ----------------------------------------------------------------
[Editor: Delete UTI 092.]
3 On the other hand
[420:7] ------------------------------------------------------------------
[Editor: insert "= ABS(FRACTION(X)) * RADIX(X) / EPSILON(X)" after "bp ".]
[420:9] ------------------------------------------------------------------
[Editor: "zero" => "IEEE VALUE(X,IEEE POSITIVE INF) (14.1, 14.10.36)" or
"zero" "positive IEEE infinity".]
[420:10+] ----------------------------------------------------------------
[Editor: Delete UTI 092.]