Patent US4553114A successfully refreshed from Google Patents.
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EP0145465A2
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Floating-point addition/subtraction system
Assignee: Fujitsu Ltd
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Filing: 1984-12-07
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Granted: —
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Expires: 2004-12-07
Abstract
Abstract @ A system of floating-point addition/subtraction for two sets of data includes a first shifting control data generating unit (11), a second shifting control data generating unit (12), a first shifting unit (21, 22), and a second shifting unit (31, 32). The first shifting control data generating unit (11) generates shifting control data based on a comparison between lower bits of the characteristics of the two sets of data. The second shifting control data generating unit (12) generates shifting control data based on a comparison between the entire bits of the characteristics of the two sets of data. Digit position alignment between the fractions of the two sets of data is attained by generating fine shifting control data in the first shifting control data generating unit (11), carrying out a fine shifting operation in the first shifting unit (21, 22) based on the fine shifting control data while at the same time generating rough shifting control data in the second shifting control data generating unit (12), and then carrying out a rough shifting operation in the second shifting unit (31, 32) based on the rough shifting control data to complete digit position alignment.
Inventors
- 👤 Masayuki Ikeda
- 👤 Kohichi Ueda
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-01 22:38
CPC Classifications
G; G06; G06F; G06F7/00; G06F7/38; G06F7/48; G06F7/483; G06F7/485; G06F7/50; G06F7/499; G06F7/49905; G06F7/49936
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
234 words
A system of floating-point addition/subtraction for two sets of data in which a comparison calculation between the characteristics of said two sets of data is carried out to generate - shifting control data for achieving digit position alignment between the fractions of said two sets of data and a shifting operation is carried out on the basis of said generated shifting control data, said system comprising: a first shifting control data generating means for generating shifting control data based on a comparison between - lower bits of the characteristics of said two sets of data; a second shifting control data generating means for generating shifting control data based on a comparison between the entire bits of the characteristics of said two sets of data; a first shifting means for realizing digit position alignment between the fractions of said two sets of data based on the shifting control data generated by said first shifting control data generating means; a second shifting means for realizing digit position alignment between the fractions of said two sets of data based on the shifting control data generated by said second shifting control data generating means; and a calculation means for carrying out addition based on outputs from said second shifting means; the digit position alignment between the fractions of said two sets of data being achieved by carrying out shifting control data generation in parallel with a shifting operation.
Claim 2
Independent Claim
234 words
A system of floating-point addition/subtraction for two sets of data in which a comparison calculation between the characteristics of said two sets of data is carried out to generate - shifting control data for achieving digit position alignment between the fractions of said two sets of data and a shifting operation is carried out on the basis of said generated shifting control data, said system comprising: a first shifting control data generating means for generating shifting control data based on a comparison between - lower bits of the characteristics of said two sets of data; a second shifting control data generating means for generating shifting control data based on a comparison between the entire bits of the characteristics of said two sets of data; a first shifting means for realizing digit position alignment between the fractions of said two sets of data based on the shifting control data generated by said first shifting control data generating means; a second shifting means for realizing digit position alignment between the fractions of said two sets of data based on the shifting control data generated by said second shifting control data generating means; and a calculation means for carrying out addition based on outputs from said second shifting means; the digit position alignment between the fractions of said two sets of data being achieved by carrying out shifting control data generation in parallel with a shifting operation.
Claim 3
Dependent Claim
35 words
A system according to claim 1, further comprising a means for non-zero leftmost digit detection and shift amount calculation; a means for characteristic correction; and a means for exceptional event detection and condition code production.
Claim 4
Dependent Claim
151 words
A method of operating a system as claimed in claim 1, or 2, comprising the steps of: generating first shifting control data using the first shifting control data generating means; effecting a first shifting comprising shifting of the digit positions of the fraction of one of said two sets of data based on said first shifting control data, to partially achieve digit position alignment between the fractions of said two sets of data, and at the same time generating second shifting control data using the second shifting control data generating means; effecting a second shifting of the digit positions of the fraction of said one of said two sets of data based on said second shifting control data, to completely achieve digit position alignment between the fractions of said two sets of data; and carrying out an addition based on the outputs from said second shifting means, using the calculation means.
Claim 5
Dependent Claim
75 words
A method as claimed in claim 3, wherein said first shifting comprises a fine shifting of the digit positions of the fraction of said one of said two sets of data, and said second shifting is a rough shifting of the digit positions of the fraction of said one of said two sets of data, which together with said first shifting completely achieves digit position alignment between the fractions of said two sets of data.
Claim 6
Dependent Claim
33 words
A method as claimed in claim 3, or 4, wherein that one of said two sets of data having the smaller characteristic has said first shifting and said second shifting effected upon it.
References Cited (Backward Citations)
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