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HandWiki. Pentium FDIV Bug. Encyclopedia. Available online: https://encyclopedia.pub/entry/32969 (accessed on 13 September 2026).
HandWiki. Pentium FDIV Bug. Encyclopedia. Available at: https://encyclopedia.pub/entry/32969. Accessed September 13, 2026.
HandWiki. "Pentium FDIV Bug" Encyclopedia, https://encyclopedia.pub/entry/32969 (accessed September 13, 2026).
HandWiki. (2022, November 04). Pentium FDIV Bug. In Encyclopedia. https://encyclopedia.pub/entry/32969
HandWiki. "Pentium FDIV Bug." Encyclopedia. Web. 04 November, 2022.
Pentium FDIV Bug
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The content is sourced from: https://handwiki.org/wiki/Software:Pentium_FDIV_bug

The Pentium FDIV bug is a hardware bug affecting the floating point unit (FPU) of the early Intel Pentium processors. Because of the bug, the processor might return incorrect binary floating point results when dividing a number. The bug was discovered in 1994 by Professor Thomas R. Nicely at Lynchburg College. Intel attributed the error to missing entries in the lookup table used by the floating-point division circuitry. The severity of the FDIV bug is debated. Though rarely encountered by most users (Byte magazine estimated that 1 in 9 billion floating point divides with random parameters would produce inaccurate results), both the flaw and Intel's initial handling of the matter were heavily criticized by the tech community. In December 1994, Intel recalled the defective processors. In January 1995, Intel announced "a pre-tax charge of $475 million against earnings, ostensibly the total cost associated with replacement of the flawed processors."

floating-point division floating point fpu

References

  1. Tom R. Halfhill (March 1995). "An error in a lookup table created the infamous bug in Intel's latest processor" (– Scholar search). BYTE (March 1995). Archived from the original on February 9, 2006. https://web.archive.org/web/20060209005434/http://www.byte.com/art/9503/sec13/art1.htm. Retrieved 2006-12-19. 
  2. Nicely, Thomas (August 19, 2011). "Pentium FDIV flaw FAQ". http://www.trnicely.net/pentbug/pentbug.html. 
  3. Alexander Wolfe. "Intel fixes a Pentium FPU glitch". http://davefaq.com/Opinions/Stupid/Pentium.html#glitch. 
  4. "Intel adopts upon-request replacement policy on Pentium processors with floating point flaw; Will take Q4 charge against earnings". Business Wire. 1994-12-20. http://findarticles.com/p/articles/mi_m0EIN/is_1994_Dec_20/ai_15939945. Retrieved 2006-12-24. 
  5. "How many engineers does it take to change a lightbulb?". Boiledbeans. 20 April 2009. http://www.boiledbeans.net/2009/04/20/how-many-engineers-does-it-take-to-change-a-lightbulb/. Retrieved 10 November 2009. 
  6. "How number theory got the best of the Pentium chip". Science 267 (5195): 175. 1995-01-13. doi:10.1126/science.267.5195.175. PMID 17791336.  https://dx.doi.org/10.1126%2Fscience.267.5195.175
  7. "FDIV Replacement Program: Frequently asked questions". Intel. 2009-03-20. http://www.intel.com/support/processors/pentium/sb/CS-012748.htm. Retrieved 2009-11-10. 
  8. "Pentium FDIV bug - a Picture". Kansas University Institute for Policy and Social Research. 1994-11-30. http://www.ipsr.ku.edu/stafffil/hoyle/pentium_fdiv/. Retrieved 2010-11-03. 
  9. "Ivars Peterson's MathTrek: Pentium Bug Revisited". Mathematical Association of America. https://www.maa.org/mathland/mathland_5_12.html. 
  10. Slob, Arie. "Windows 95 Troubleshooting: How to Check for a Faulty Math Coprocessor". http://www.helpwithwindows.com/windows95/troub-58.html. 
  11. "Pentnt". Microsoft. September 11, 2009. https://technet.microsoft.com/en-us/library/bb490967.aspx. 
  12. https://docs.microsoft.com/en-us/windows-server/administration/windows-commands/pentnt
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