Reports of New Intel Floating Point Flaw Hit the Internet; Story Posted on EE Times Online at

May 5, 1997

Reports of a new floating-point bug involving Intel (NASDAQ: INTC) have hit the Internet, according to CMP Media's EE Times Online ( This time, the purported glitch involves Intel's high-end Pentium Pro and Pentium II processors.

"It's a bug in the floating-point integer store," said Robert Collins, who added the he will post details today on his "Intel Secrets" Web page, found at

"If you have a floating-point number and then try to store it as an integer, where the store would result in an overflow, the processor signals the wrong type of error," Collins told EE Times. "What the processor should do is signal and invalid-operand error; it does not."

According to Collins, the Pentium Pro and Pentium II chips will instead report that an overflow has occurred. Although this might seem to be the correct action, Collins said that Pentium Pro manual notes that an invalid- operand error is in fact a proper response.

Intel said it was keeping a close watch on Collins' Web site. An Intel spokesman said the company called Collins, but Collins declined to provide any information in advance of his posting.

"We won't know what we've got until we see it on his Web site," said Intel spokesman Howard High. "We'll start investigating and characterizing it once we get the information."

High added that Intel may post a response at some point on the newsgroup. However, he said it might be some time before the complete results of any investigation are available. High also told EE Times that the purported glitch may be one that's already been identified in the errata document for the Pentium II, which will be officially unveiled by the microprocessor giant this Wednesday.

The new floating-point report is reminiscent of the flaw that plagued Intel's Pentium chip in November, 1994. That flaw, first reported by EE Times, resulted in an eventual $475 million charge against the company's earnings.

EE Times Online is the Web arm of CMP Media Inc.'s EE Times. EE Times delivers news of both business and technology to engineers and technical/corporate managers at electronics and computer systems manufacturers in the United States.

CMP Media Inc. provides publishing, marketing and information services to the broad high-technology spectrum -- the builders, sellers and users of technology -- through print and electronic media. All of CMP's publications and online products can be accessed through the company's TechWeb® site on the World Wide Web ( Print titles include EE Times, Computer Reseller News, InformationWeek and WINDOWS Magazine.

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SOURCE: CMP Media Inc.

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