Field Name

Description

IBETA

The
radix in which numbers are represented. A longword integer.

IT

The number of baseIBETA digits in the
floatingpoint mantissa M. A longword integer.

IRND

A code in the range 0  5 giving information on what type of
rounding is done and how underflow is handled. A longword integer.

NGRD

The number of "
guard digits" used when truncating the product of two mantissas. A longword integer.

MACHEP

The exponent of the smallest power of IBETA that, added to 1.0, gives something different from 1.0. A longword integer.

NEGEP

The exponent of the smallest power of IBETA that, subtracted from 1.0, gives something different from 1.0. A longword integer.

IEXP

The number of bits in the exponent. A longword integer.

MINEXP

The smallest value of IBETA consistent with there being no leading zeros in the mantissa. A longword integer.

MAXEXP

The smallest positive value of IBETA that causes
overflow. A longword integer.

EPS

The floatingpoint number IBETA^{
MACHEP}
, loosely referred to as the "
floatingpoint precision."

EPSNEG

The floatingpoint number IBETA^{
NEGEP}
, which is another way of determining floatingpoint precision.

XMIN

The floatingpoint number IBETA^{
MINEXP}
, generally the smallest usable floatingpoint value.

XMAX

The largest usable floatingpoint value, defined as the number (1EPSNEG)xIBETA^{
MAXEXP}
·
