notes:ieee_754-1985

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notes:ieee_754-1985 [2013/02/24 00:11] andy [Normalised Values] |
notes:ieee_754-1985 [2013/02/24 00:12] andy [Zero] |
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^ Significand | Zero | | ^ Significand | Zero | | ||

- | A value of exactly zero is represented by a exponent and significand of zero. The sign bit may be set or unset and IEEE 754 has the concept of both a positive and negative zero. For standard comparisons, however, these will both compare equal with zero, so the comparison **-0.0 < 0.0** yields **false**. | + | A value of exactly zero is represented by a exponent and significand of zero. The sign bit may be set or unset and IEEE 754 has the concept of both a positive and negative zero. For standard comparisons, however, these will both compare equal with zero, so the comparison $-0.0 < 0.0$ yields **false**. |

To determine the sign of a floating point value including zero, the ''[[man>copysign|copysign()]]'' function can be used with a non-zero value, or the ''[[man>signbit|signbit()]]'' macro can be used more directly on some platforms (not available on WinCE, for example). | To determine the sign of a floating point value including zero, the ''[[man>copysign|copysign()]]'' function can be used with a non-zero value, or the ''[[man>signbit|signbit()]]'' macro can be used more directly on some platforms (not available on WinCE, for example). |

notes/ieee_754-1985.txt · Last modified: 2013/02/24 00:18 by andy