floating underflow
(foldoc) | underflow
floating point underflow
floating underflow
(or "floating point underflow", "floating
underflow", after "overflow") A condition that can occur
when the result of a floating-point operation would be
smaller in magnitude (closer to zero, either positive or
negative) than the smallest quantity representable. Underflow
is actually (negative) overflow of the exponent of the
floating point quantity. For example, an eight-bit {twos
complement} exponent can represent multipliers of 2^-128 to
2^127. A result less than 2^-128 would cause underflow.
Depending on the processor, the programming language and the
run-time system, underflow may set a status bit, raise an
exception or generate a hardware interrupt or some
combination of these effects. Alternatively, it may just be
ignored and zero substituted for the unrepresentable value,
though this might lead to a later divide by zero error which
cannot be so easily ignored.
(2006-11-09)
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