新しい可変長指数部浮動小数点数表現形式の提案  [in Japanese] New Floating Point Number Formats with Variable Length Exponent  [in Japanese]

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Abstract

可変長指数部浮動小数点数表現形式とは指数の大きさによって指数部の長さが変化することにより、通常の浮動小数点数よりも高い精度や広い表現範囲が実現できる浮動小数点数の諸形式である。本論文では従来の方式の問題点を考察し、誤差解析やハードウェアへ実装などを考慮して、表現形式の設計基準の中に()変換にシフトが不要である ()指数部のビット長の変化が最大1であるの2点を盛り込むことを提案する。そしてこの基準を満たす表現形式をいくつか提示し、従来のものをも含めて精度や表現範囲を比較検討した。また、Kraftの不等式を用いた二重指数分割方式に関するいくつかの理論的な結果を示した。Some researchers proposed floating point number formats that attain higher precision and wider representation range than the usual formats by varing the length of the exponent. This paper consider the problems of those formats, and proposes to require that (1) encoding and decoding need no shifter and (2) the length of the exponent increases by at most one bit. Some new formats that meets those requirements are presented, and their precisions are evaluated. Some analytical results obtained from the Kraft's in equation about the double exponential cut formats are also presented.

Some researchers proposed floating point number formats that attain higher precision and wider representation range than the usual formats by varing the length of the exponent. This paper consider the problems of those formats, and proposes to require that (1)encoding and decoding need no shifter and (2)the length of the exponent increases by at most one bit. Some new formats that meets those requirements are presented, and their precisions are evaluated. Some analytical results obtained from the Kraft's inequation about the double exponential cut formats are also presented.

Journal

  • IPSJ SIG Notes

    IPSJ SIG Notes 1997(37(1997-HPC-066)), 31-36, 1997-05-09

    Information Processing Society of Japan (IPSJ)

References:  13

Cited by:  1

Codes

  • NII Article ID (NAID)
    110002932023
  • NII NACSIS-CAT ID (NCID)
    AN10463942
  • Text Lang
    JPN
  • Article Type
    Journal Article
  • Data Source
    CJP  CJPref  NII-ELS  IPSJ 
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