{"title":"It takes six ones to reach a flaw [Pentium processor]","authors":"T. Coe, P. T. P. Tang","doi":"10.1109/ARITH.1995.465365","DOIUrl":null,"url":null,"abstract":"The initial release of the Pentium processor has a flaw in its radix-4 SRT division implementation. It is widely-known that five entries were missing in the lookup table, yielding reduced-precision quotients occasionally. In this paper, we use mathematical techniques to analyze the divisors that can possibly cause failures. In particular, we show that Bits 5 through 10 (where Bit 0 is the MSB) of such divisors must be all ones. This result is useful in compiler-level software patches for systems with unreplaced chips; and we believe that the techniques used here are applicable in analyzing SRT division as well as other hardware algorithms for floating-point arithmetic.<<ETX>>","PeriodicalId":332829,"journal":{"name":"Proceedings of the 12th Symposium on Computer Arithmetic","volume":null,"pages":null},"PeriodicalIF":0.0000,"publicationDate":"1995-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"15","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Proceedings of the 12th Symposium on Computer Arithmetic","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1109/ARITH.1995.465365","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 15
Abstract
The initial release of the Pentium processor has a flaw in its radix-4 SRT division implementation. It is widely-known that five entries were missing in the lookup table, yielding reduced-precision quotients occasionally. In this paper, we use mathematical techniques to analyze the divisors that can possibly cause failures. In particular, we show that Bits 5 through 10 (where Bit 0 is the MSB) of such divisors must be all ones. This result is useful in compiler-level software patches for systems with unreplaced chips; and we believe that the techniques used here are applicable in analyzing SRT division as well as other hardware algorithms for floating-point arithmetic.<>