DRAFT IEEE Standard for Binary Floating-Point Arithmetic - Sonic.net

DRAFT IEEE Standard for Floating-Point Arithmetic – 2003 August 12 10:20
more exceptions (listed in section 7) by invoking the default (section
7) or user-specified alternate (section 8) handling. Note that
“exception” and “signal” are defined in diverse ways in different
programming environments.
significand. A component of an unencoded binary or decimal floating-point number
containing its significant digits. The component of a binary floating-point number that
consists of an explicit or implicit leading bit to the left of its implied binary point and a
fraction field to the right. In this standard, the significand is represented as an integer.
By redefining the bias, the significand may be thought of as an integer, a fraction, or
some other fixed-point form.
status flag. A variable that may take two states, raised or lowered set and clear. A
user may can raise a status flag, lower it, test it, clear a flag, copy it, or restore it to a
previous state. When raised set, a status flag may convey contain additional systemdependent
information, possibly inaccessible to some users. The operations of this
standard, when exceptional, can may as a side effect raise set some of the following
status flags: inexact result, underflow, overflow, divide by zero, and invalid operation.
[A program that does not inherit status flags from another source,
begins execution with all status flags lowered.]
subnormal denormalized number. In a particular format, a nonzero floatingpoint
number with magnitude less than the magnitude of that format's smallest normal
number. A subnormal number cannot be represented in that format with an implicit
(binary) or explicit (decimal) nonzero leading significand digit. exponent has a
reserved value, usually the format's minimum, and whose explicit or implicit leading
significand bit is zero. Supersedes 754–1985's denormalized number. §2
user. Any person, hardware, or program not itself specified by this standard, having
access to and controlling those operations of the programming environment specified
in this standard.
Copyright © 2003 by the Institute of Electrical and Electronics Engineers, Inc. This document is an unapproved
draft of a proposed IEEE-SA Standard - USE AT YOUR OWN RISK. See statement on page 1.
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