Tue, 17 Nov 1992 18:58:37 GMT

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IEEE arithmetic handling jim@meiko.co.uk (1992-11-11) |

Re: IEEE arithmetic handling tmb@arolla.idiap.ch (1992-11-16) |

Re: IEEE arithmetic handling eggert@twinsun.com (1992-11-16) |

Re: IEEE arithmetic handling bill@amber.csd.harris.com (1992-11-16) |

Re: IEEE arithmetic handling jlg@cochiti.lanl.gov (1992-11-17) |

Re: IEEE arithmetic handling eggert@twinsun.com (1992-11-17) |

Re: IEEE arithmetic handling tmb@arolla.idiap.ch (1992-11-18) |

Re: IEEE arithmetic handling bart@cs.uoregon.edu (1992-11-19) |

Re: IEEE arithmetic handling bill@amber.csd.harris.com (1992-11-20) |

Re: IEEE arithmetic handling bill@amber.csd.harris.com (1992-11-20) |

Re: IEEE arithmetic handling Dik.Winter@cwi.nl (1992-11-23) |

Re: IEEE arithmetic handling bright@nazgul.uucp (Walter Bright) (1993-01-07) |

Newsgroups: | comp.compilers |

From: | eggert@twinsun.com (Paul Eggert) |

Organization: | Twin Sun, Inc |

Date: | Tue, 17 Nov 1992 18:58:37 GMT |

References: | 92-11-041 92-11-087 |

Keywords: | arithmetic |

bill@amber.csd.harris.com (Bill Leonard) writes:

*>Fortran does not *conflict* with the IEEE vis-a-vis negative zero. It merely*

*>says that the processor must never *output* a negatively-signed zero.*

But that conflicts with IEEE Std 754-1985, section 5.6, which requires

that converting a number from binary to decimal and back be the identity

if the proper precision and rounding is used. The Fortran standard says

-0.0 must be output as 0.0; this loses information.

One way to work around the problem is to supply IEEE-specific

binary/decimal conversion routines to the Fortran programmer, but there's

no standard for this, and most implementors don't bother. So in practice,

I'm afraid that Fortran and IEEE are indeed in conflict here.

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