floating-point

1 definition found

floating-point - Free On-line Dictionary of Computing (26 May 2007) :

  floating-point
  
     <programming, mathematics> A number representation consisting
     of a mantissa, M, an exponent, E, and a radix (or
     "base").  The number represented is M*R^E where R is the
     radix.
  
     In science and engineering, exponential notation or
     scientific notation uses a radix of ten so, for example, the
     number 93,000,000 might be written 9.3 x 10^7 (where ^7 is
     superscript 7).
  
     In computer hardware, floating point numbers are usually
     represented with a radix of two since the mantissa and
     exponent are stored in binary, though many different
     representations could be used.  The IEEE specify a
     standard representation which is used by many hardware
     floating-point systems.  Non-zero numbers are normalised so
     that the binary point is immediately before the most
     significant bit of the mantissa.  Since the number is
     non-zero, this bit must be a one so it need not be stored.  A
     fixed "bias" is added to the exponent so that positive and
     negative exponents can be represented without a sign bit.
     Finally, extreme values of exponent (all zeros and all ones)
     are used to represent special numbers like zero and positive
     and negative infinity.
  
     See also floating-point accelerator, floating-point unit.
  
     Opposite: fixed-point.
  
     (2006-11-09)