HP-UX Floating-Point Guide

230 Glossary
Glossary
most significant word In
double-precision and quad-
precision floating-point
formats, the 32-bit word in the
representation that contains the
sign bit, the exponent field, and
the first part of the fraction. See
also least significant word.
multiplication One of the basic
operations defined by the IEEE
standard.
NaN (Not-a-Number) A
floating-point value that is
represented by a sign bit, a
fraction with at least one bit set
to 1, and an exponent with all
bits set to 1. See also signaling
NaN (SNaN), quiet NaN
(QNaN).
natural alignment The
alignment that corresponds to the
length of the object. For example,
the natural alignment of an HP C
int is 4-byte alignment.
non-aware A version of a
comparison assertion that
behaves the same as the aware
version, except that if either or
both operands is a quiet NaN
(QNaN), it also signals an invalid
operation condition for the <,
<=, >, and >= assertions. See also
aware.
normal See normalized value.
normalization bit See fraction
implicit bit.
normalized value A floating-
point value that is represented by
a sign bit, a fraction, and an
exponent whose bits are not all
zeros and not all ones. A
normalized value has a magnitude
greater than any denormalized
value and less than infinity.
numerically unstable See ill-
conditioned.
operand errors See invalid
operation condition.
operation errors See invalid
operation condition.
overflow condition The
exception condition that occurs
when a floating-point operation
attempts to produce a result whose
magnitude, after rounding, is
greater than the maximum
representable value.
performance bottlenecks The
sections of code that require the
most execution time.