Intel corrected the bug in June of 1994, and any new Pentium computer sold after January of 1995 probably has the newer corrected chip in it. Intel will also replace upon request any Pentium chip which has the floating point division flaw with a new one, just ask. I myself have never bothered replacing my flawed Pentium chip. The flaw is too insignificant to affect everyday users like myself. All my software runs just fine with no problems, and quite fast I might add. Actually that part about no problems is a lie -- I have endless problems with bugs in software for IBM-PC compatible computers, but none of the bugs are the result of the Pentium's floating point division flaw explained here.

For most people the flaw itself is just an entertaining curiosity since it's rare and the error in precision when it does occur is small. The flaw does arouse one's curiosity though, and it is quite interesting to study the details behind the flaw, as it brings together many aspects of computer science. Like any technical field, computer science can be made easy to understand, or it can be made difficult to understand. I hope most people find this paper easy to understand.

-David W. Deley June 1995

CHAPTER 1: REVIEW

CHAPTER 2: REVIEW

2.1 | EXAMPLE | |

2.2 | ABSTRACT DIVISON | |

2.3 | THE ITERATIVE FORMULA FOR DIVISON | |

2.4 | BOUNDS ON RESULTING REMAINDER | |

2.5 | LOOKUP TABLE | |

2.6 | NEGATIVE QUOTIENT DIGITS |

CHAPTER 3: REVIEW

3.1 | THE SRT DIVISION ALGORITHM | |

3.2 | THE ITERATIVE FORMULA FOR DIVISION BASE 4 | |

3.3 | BOUNDS ON RESULTING REMAINDER | |

3.4 | THE PENTIUM LOOKUP TABLE (P-D PLOT) | |

3.5 | ITERATION USING THE P-D PLOT AS A LOOKUP TABLE |

CHAPTER 4 | EXAMPLE OF BUG | |

CHAPTER 5 | OBSERVATIONS ON HITTING THE ERROR CELL | |

CHAPTER 6 | TOPICS FOR FURTHER STUDY | |

CHAPTER 7 | HISTORY OF THE BUG'S DISCOVERY | |

CHAPTER 8 | HOW TO TEST FOR THE PENTIUM BUG | |

CHAPTER 9 | PENTIUM JOKES | |

REFERENCES |

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