Patent US3633018A successfully refreshed from Google Patents.
US3633018A
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Digital division by reciprocal conversion technique
Assignee: International Business Machines Corp
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Filing: 1969-12-18
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Granted: 1972-01-04
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Expires: 1989-12-18
Abstract
Abstract A reciprocal conversion technique for obtaining the quotient of two numbers and the reciprocal of a number. A predetermined number of leading bits of the mantissa of the denominator is used as an entry into a table used for locating the required number of shifts and adds or shifts and subtracts to form a standard from of a denominator. Significant precision control and the semireciprocal of the normalized fraction is formed in successive multiplication steps. The reciprocal of the normalized fraction is formed and the quotient can thereafter be determined with a final multiplication step.
Inventors
- 👤 Huei Ling
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 14:04
CPC Classifications
G; G06; G06F; G06F7/00; G06F7/38; G06F7/48; G06F7/52; G06F7/535
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
146 words
The method of obtaining electrical signals representing the reciprocal of a number D comprising the steps of: 1. calculating electrical signals representing the left justified mantissa of D, dm; 2. adjusting said electrical signals representing said justified mantissa to obtain electrical signals representing a standard form of the number containing a desired number of leading one bits, said standard form having a fraction portion; 3. calculating electrical signals representing a precision control number; 4. calculating electrical signals represent the quantity one pulse one-half the complement of said fraction portion of said standard form; 5. multiplying said electrical signals representing said quantity by said electrical signals representing said precision control number to obtain electrical signals representing the bits of the reciprocal to a desired precision; and 6. shifting said electrical signals representing the bits of the reciprocal to account for the original left justification of said mantissa.
Claim 2
Independent Claim
146 words
The method of obtaining electrical signals representing the reciprocal of a number D comprising the steps of: 1. calculating electrical signals representing the left justified mantissa of D, dm; 2. adjusting said electrical signals representing said justified mantissa to obtain electrical signals representing a standard form of the number containing a desired number of leading one bits, said standard form having a fraction portion; 3. calculating electrical signals representing a precision control number; 4. calculating electrical signals represent the quantity one pulse one-half the complement of said fraction portion of said standard form; 5. multiplying said electrical signals representing said quantity by said electrical signals representing said precision control number to obtain electrical signals representing the bits of the reciprocal to a desired precision; and 6. shifting said electrical signals representing the bits of the reciprocal to account for the original left justification of said mantissa.
Claim 3
Dependent Claim
34 words
adjusting said electrical signals representing said justified mantissa to obtain electrical signals representing a standard form of the number containing a desired number of leading one bits, said standard form having a fraction portion;
Claim 4
Dependent Claim
34 words
adjusting said electrical signals representing said justified mantissa to obtain electrical signals representing a standard form of the number containing a desired number of leading one bits, said standard form having a fraction portion;
Claim 5
Dependent Claim
34 words
The method of claim 1 further including the step of multiplying said shifted electrical signals representing the bits of the reciprocal by a number N to obtain the quotient of N divided by D.
Claim 6
Dependent Claim
158 words
Apparatus for obtaining the reciprocal of a left-justified number D, comprising in combination; inspEction means for inspecting certain bits of the mantissa dm of said number D and supplying information defining the mathematical calculation necessary to transform said mantissa into a standard form having a desired number of leading 1 bits, said standard form having a fraction portion; first arithmetic means connected to said inspection means, including shift and addition means, for performing said defined mathematical calculation on said mantissa; precision control means connected to said first arithmetic means for calculating a precision control number as a function of said standard form; said arithmetic means for calculating the quantity one plus one-half the complement of the fraction portion of the standard form; and multiplication means for multiplying said precision control number by the quantity one pulse one-half the complement of the fraction portion of the standard form to obtain the bits of the reciprocal to the desired precision.
Claim 7
Dependent Claim
158 words
Apparatus for obtaining the reciprocal of a left-justified number D, comprising in combination; inspEction means for inspecting certain bits of the mantissa dm of said number D and supplying information defining the mathematical calculation necessary to transform said mantissa into a standard form having a desired number of leading 1 bits, said standard form having a fraction portion; first arithmetic means connected to said inspection means, including shift and addition means, for performing said defined mathematical calculation on said mantissa; precision control means connected to said first arithmetic means for calculating a precision control number as a function of said standard form; said arithmetic means for calculating the quantity one plus one-half the complement of the fraction portion of the standard form; and multiplication means for multiplying said precision control number by the quantity one pulse one-half the complement of the fraction portion of the standard form to obtain the bits of the reciprocal to the desired precision.
Claim 8
Dependent Claim
8 words
calculating electrical signals representing a precision control number;
Claim 9
Dependent Claim
8 words
calculating electrical signals representing a precision control number;
Claim 10
Dependent Claim
19 words
calculating electrical signals represent the quantity one pulse one-half the complement of said fraction portion of said standard form;
Claim 11
Dependent Claim
19 words
calculating electrical signals represent the quantity one pulse one-half the complement of said fraction portion of said standard form;
Claim 12
Dependent Claim
26 words
The combination of claim 3 further including means for adjusting said bits of said reciprocal to account for said left justification to obtain the desired reciprocal.
Claim 13
Dependent Claim
24 words
The combination of claim 3 further including means for multiplying a number N by the bits of the reciprocal to obtain the quotient N/D.
Claim 14
Dependent Claim
31 words
multiplying said electrical signals representing said quantity by said electrical signals representing said precision control number to obtain electrical signals representing the bits of the reciprocal to a desired precision; and
Claim 15
Dependent Claim
31 words
multiplying said electrical signals representing said quantity by said electrical signals representing said precision control number to obtain electrical signals representing the bits of the reciprocal to a desired precision; and
Claim 16
Dependent Claim
20 words
shifting said electrical signals representing the bits of the reciprocal to account for the original left justification of said mantissa.
Claim 17
Dependent Claim
20 words
shifting said electrical signals representing the bits of the reciprocal to account for the original left justification of said mantissa.
References Cited (Backward Citations)
US3234369A
Cited
US3508038A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-01-03 | 1975-07-05 | 1976-01-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-01-03 | 1979-07-05 | 1980-01-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-01-03 | 1983-07-05 | 1984-01-04 | $7700.00 | Window Closed / Lapsed |