US4282581A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Automatic overflow/imminent overflow detector
Assignee: Unisys Corp
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Filing: 1979-10-15
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Granted: 1981-08-04
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Expires: 1999-10-15
Abstract
Abstract An apparatus for automatically detecting overflow and imminent overflow conditions as data is transferred from an accumulator to a postscaler. As the data is output from the accumulator, the appropriateness of the predetermined scale factor to be used by the postscaler is determined. If an overflow condition will occur at the output of the postscaler, an overflow signal is generated, and the output of the postscaler is forced to +/-1. If the output of the postscaler will produce data with an absolute value of greater than 1/2, an imminent overflow signal is generated.
Inventors
- 👤 David W. Bondurant
- 👤 Richard J. Martin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 05:21
CPC Classifications
G; G06; G06F; G06F7/00; G06F7/38; G06F7/48; G06F7/544; G06F7/5443; G06F7/4806; G06F7/499; G06F7/49905; G06F7/4991
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
134 words
In a digital processor, having an arithmetic unit, and having means for supplying a scale factor for scaling a resultant produced by said arithmetic unit, an apparatus for postscaling said resultant comprising: a shifter means responsively coupled to said arithmetic unit and said supplying means for shifting said resultant a number of radix places corresponding to said scale factor supplied by said supplying means; a detector means responsively coupled to said supplying means and said arithmetic unit for generating an overflow signal whenever said scale factor causes said shifter to shift said resultant a number of radix places causing an overflow condition; and means responsively coupled to said shifter means and said detector means for forcing the output of said shifter means to a predetermined value whenever said detector means detects an overflow condition.
Claim 2
Dependent Claim
134 words
In a digital processor, having an arithmetic unit, and having means for supplying a scale factor for scaling a resultant produced by said arithmetic unit, an apparatus for postscaling said resultant comprising: a shifter means responsively coupled to said arithmetic unit and said supplying means for shifting said resultant a number of radix places corresponding to said scale factor supplied by said supplying means; a detector means responsively coupled to said supplying means and said arithmetic unit for generating an overflow signal whenever said scale factor causes said shifter to shift said resultant a number of radix places causing an overflow condition; and means responsively coupled to said shifter means and said detector means for forcing the output of said shifter means to a predetermined value whenever said detector means detects an overflow condition.
Claim 3
Dependent Claim
49 words
An apparatus according to claim 1 wherein said detector further comprises: means responsively coupled to said supplying means and said arithmetic unit for generating an imminent overflow signal whenever said scale factor causes said shifter to shift said resultant a number of radix places causing an imminent overflow condition.
Claim 4
Independent Claim
129 words
An apparatus for arithmetic processing comprising: multiply-accumulate circuit means for generating a resultant from the arithmetic manipulation of an input; means for supplying a scale factor; shifter means responsively coupled to said multiply/accumulate circuit means and said supplying means for shifting said resultant a number of radix places corresponding to said scale factor; detector means responsively coupled to said supplying means and said multiply/accumulate circuit means for determining whether an overflow condition exists as a result of said shifter means shifting said resultant said number of radix places corresponding to said scale factor; and means responsively coupled to said detector means and said shifter means for forcing an output of said shifter means to a predetermined maximum absolute value whenever said detector means determines that said overflow condition exists.
Claim 5
Independent Claim
129 words
An apparatus for arithmetic processing comprising: multiply-accumulate circuit means for generating a resultant from the arithmetic manipulation of an input; means for supplying a scale factor; shifter means responsively coupled to said multiply/accumulate circuit means and said supplying means for shifting said resultant a number of radix places corresponding to said scale factor; detector means responsively coupled to said supplying means and said multiply/accumulate circuit means for determining whether an overflow condition exists as a result of said shifter means shifting said resultant said number of radix places corresponding to said scale factor; and means responsively coupled to said detector means and said shifter means for forcing an output of said shifter means to a predetermined maximum absolute value whenever said detector means determines that said overflow condition exists.
Claim 6
Dependent Claim
33 words
An apparatus according to claim 3 wherein said detector means further comprises: circuit means responsively coupled to said supplying means and said multiply/accumulate circuit means for determining that an imminent overflow condition exists.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-08-03 | 1985-02-02 | 1985-08-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-08-03 | 1989-02-02 | 1989-08-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-08-03 | 1993-02-02 | 1993-08-04 | $7700.00 | Window Closed / Lapsed |