HP-UX Floating-Point Guide

232 Glossary
Glossary
representable value closest to
negative infinity (that is, the
algebraically lesser value).
round toward zero The IEEE
rounding mode that specifies
that the result of an operation
should be the representable value
closest to zero (that is, the value
with the smaller magnitude).
rounding The act of choosing a
representable value when the
exact value produced by a
floating-point operation is not
representable. The IEEE
standard specifies four methods
of rounding, called rounding
modes. See also rounding error.
rounding error The error that
occurs when the result of an
operation is rounded to the nearest
representable value using an
algorithm specified by the
rounding mode.
rounding mode One of four
rounding methods specified by
the IEEE standard: round to
nearest (the default), round
toward +INFINITY, round
toward −INFINITY, and round
toward zero.
shared library A collection of
object modules. When the linker
scans a shared library, it does not
copy modules into the application’s
code section, as it does with an
archive library. Instead, the
linker preserves information in the
application’s code section about
which unresolved references were
resolved in each shared library. At
run time, the shared library is
mapped into memory.
sign bit In a floating-point
representation, the bit that
indicates the sign of the value. In
IEEE formats, the sign bit is the
leftmost bit. See also exponent,
fraction.
signal handler See trap
handler.
signaling NaN (SNaN) A NaN
(Not-a-Number) that generates
an invalid operation condition
whenever it is used. On HP 9000
systems, an SNaN has the most
significant bit of the fraction set
to 1. See also quiet NaN (QNaN).
significand See fraction.
single-precision An IEEE
floating-point format in which
the value occupies 32 bits: 1 bit for
the sign, 8 bits for the exponent,