Mon, 23 Nov 1992 20:32:17 GMT

Related articles |
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[4 earlier articles] |

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: | Dik.Winter@cwi.nl (Dik T. Winter) |

Organization: | CWI, Amsterdam |

Date: | Mon, 23 Nov 1992 20:32:17 GMT |

References: | 92-11-041 92-11-121 |

Keywords: | arithmetic |

jlg@cochiti.lanl.gov (J. Giles) writes:

> This is easily accomplished. Let `b' be the base of your floating point

> representation and let `p' be the number of digits in your significand.

> Then, output followed by input is the identity if:

>

> (m-1) p

> 10 >= b - 1

>

> Where `m' is the number of decimal digits output.

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

> This doesn't seem to work. Take an example: let b=2, p=4. Thus

> p

> b - 1 = 15, so m=3. Now consider the binary number 1.001, which has

> 4 binary digits (as dicated by p=4). This number, in decimal, is exactly

> 1.125, which requires 4 decimal digits, thus exceeding the number m.

No problem, you output 1.12 or 1.13 whatever you fancy. Now when you read

that back in you get your original back. Unless your read routines are

wrong of course and read 1.12 or 1.13 back in as 1.25 or 1.00. That is

the major part, not that output is exact but that output followed by input

is exact.

> (Of course, a computer using base 3 would be pretty strange.

> :-)

On occasion on alt.folklore.computers you will read about that Russian

ternary beast.

--

dik t. winter, cwi, kruislaan 413, 1098 sj amsterdam, nederland

home: bovenover 215, 1025 jn amsterdam, nederland; e-mail: dik@cwi.nl

--

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