US5293558A
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US
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Multiplication, division and square root extraction apparatus
Assignee: Hitachi Ltd
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Filing: 1989-11-02
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Granted: 1994-03-08
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Expires: 2009-11-02
Abstract
Abstract A multiplication, division and square root extraction apparatus which calculates the solutions to addition, division and square root extraction functions by approximation using iteration has a multiplier, an adder-subtracter and a shifter of prescribed bit width connected to a bus. Iteration is conducted by inputting the output of the multiplier to the adder-subtracter or the shifter and returning the result to the input of the multiplier via the bus. A shifter and an arithmetic and logic unit connected to a second bus connected to the aforesaid bus via a switch have a greater bit width than the prescribed bit width and are used for large scale calculations, thus preventing a reduction in processing speed.
Inventors
- 👤 Masahisa Narita
- 👤 Hisashi Kaziwara
- 👤 Takeshi Asai
- 👤 Shigeki Morinaga
- 👤 Hiroyuki Kida
- 👤 Mitsuru Watabe
- 👤 Tetsuaki Nakamikawa
- 👤 Shunpei Kawasaki
- 👤 Junichi Tatezaki
- 👤 Norio Nakagawa
- 👤 Yugo Kashiwagi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 04:38
CPC Classifications
G; G06; G06F; G06F7/00; G06F7/38; G06F7/48; G06F7/52; G06F7/57; G06F7/535; G06F7/544; G06F7/552; G06F7/5525; G06F2207/00; G06F2207/38; G06F2207/3804; G06F2207/3808; G06F2207/3812; G06F2207/3816; G06F2207/535; G06F2207/5355; G06F2207/5356; G06F7/483; G06F7/487; G06F7/4873; G06F7/499; G06F7/49942; G06F7/49947; G06F7/49957
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
221 words
A multiplication, division and square root extraction apparatus which, for carrying out multiplication, division and square root extraction calculations, calculates approximate solutions of multiplication, division and square root extraction functions by iteration through repeated multiplication, addition and subtraction, said apparatus comprising: a multiplier of prescribed bit width, having first and second inputs and an output, for carrying out multiplication between respective values of a prescribed number of bits received at said first and second inputs, and for supplying the product of said values at said output; a subtractor of prescribed bit width connected to said output of said multiplier for subtracting said product from a prescribed value and for outputting the result of the subtraction; a data transfer device, connected to said output of said subtractor and said first and second inputs of said multiplier, for transferring said output of said subtractor to a selected one of said first and second inputs of said multiplier according to an iteration algorithm; and a square root extraction approximation means for calculating a first product of a square of an approximate value and the number whose square root is to be obtained, subtracting said first product from a constant, calculating a second product of the result of the subtraction, the approximate value and another constant, and providing said second product for a subsequent approximation.
Claim 2
Dependent Claim
221 words
A multiplication, division and square root extraction apparatus which, for carrying out multiplication, division and square root extraction calculations, calculates approximate solutions of multiplication, division and square root extraction functions by iteration through repeated multiplication, addition and subtraction, said apparatus comprising: a multiplier of prescribed bit width, having first and second inputs and an output, for carrying out multiplication between respective values of a prescribed number of bits received at said first and second inputs, and for supplying the product of said values at said output; a subtractor of prescribed bit width connected to said output of said multiplier for subtracting said product from a prescribed value and for outputting the result of the subtraction; a data transfer device, connected to said output of said subtractor and said first and second inputs of said multiplier, for transferring said output of said subtractor to a selected one of said first and second inputs of said multiplier according to an iteration algorithm; and a square root extraction approximation means for calculating a first product of a square of an approximate value and the number whose square root is to be obtained, subtracting said first product from a constant, calculating a second product of the result of the subtraction, the approximate value and another constant, and providing said second product for a subsequent approximation.
Claim 3
Dependent Claim
271 words
A multiplication, division and square root extraction apparatus which, for carrying out multiplication, division and square root extraction calculations, calculates approximate solutions of multiplication, division and square root extraction functions by iteration through repeated multiplication, addition and subtraction, said apparatus comprising: a multiplier of prescribed bit width, having a first and second inputs and an output, for carrying out multiplication between respective values of a prescribed number of bits received at said first and second inputs, and for supplying the product of said values at said output; a subtractor of prescribed bit width connected to said output of said multiplier for subtracting said product from a prescribed value and for outputting the result of the subtraction; a data transfer device, connected to said output of said subtractor and said first and second inputs of said multiplier, for transferring said output of said subtractor to a selected one of said first and second inputs of said multiplier according to an iteration algorithm; shift means, having a second bit width greater than the prescribed bit width of said multiplier, for shifting a result produced by said multiplier; arithmetic and logic means, having a second bit width connected to said shift means, for processing an output o the sift means and another result produced by said multiplier; and a second data transfer device connected to said data transfer device through a switch means, also connected to said shift means and said arithmetic and logic means, for transferring a product from said multiplier to said shift means and/or said arithmetic and logic means, and a result of said arithmetic and logic means to said multiplier.
Claim 4
Dependent Claim
271 words
A multiplication, division and square root extraction apparatus which, for carrying out multiplication, division and square root extraction calculations, calculates approximate solutions of multiplication, division and square root extraction functions by iteration through repeated multiplication, addition and subtraction, said apparatus comprising: a multiplier of prescribed bit width, having a first and second inputs and an output, for carrying out multiplication between respective values of a prescribed number of bits received at said first and second inputs, and for supplying the product of said values at said output; a subtractor of prescribed bit width connected to said output of said multiplier for subtracting said product from a prescribed value and for outputting the result of the subtraction; a data transfer device, connected to said output of said subtractor and said first and second inputs of said multiplier, for transferring said output of said subtractor to a selected one of said first and second inputs of said multiplier according to an iteration algorithm; shift means, having a second bit width greater than the prescribed bit width of said multiplier, for shifting a result produced by said multiplier; arithmetic and logic means, having a second bit width connected to said shift means, for processing an output o the sift means and another result produced by said multiplier; and a second data transfer device connected to said data transfer device through a switch means, also connected to said shift means and said arithmetic and logic means, for transferring a product from said multiplier to said shift means and/or said arithmetic and logic means, and a result of said arithmetic and logic means to said multiplier.
Claim 5
Dependent Claim
34 words
A multiplication, division and square root extraction apparatus according to claim 2, wherein the shift means has rounding-off means of shifting data by one or more bits and rounding off the shifted out data.
Claim 6
Dependent Claim
54 words
A multiplication, division and square root extraction apparatus according to claim 2, wherein the processing by the shift means and the arithmetic and logic means and the processing by the multiplier and the subtracter are conducted in parallel during a period when the first and second data transfer means are separated by the switch.
Claim 7
Dependent Claim
24 words
A multiplication, division and square root extraction apparatus according to claim 4, wherein the multiplier carries out a plurality of multiplications by pipeline processing.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-03-07 | 1997-09-06 | 1998-03-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-03-07 | 2001-09-06 | 2002-03-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-03-07 | 2005-09-06 | 2006-03-08 | $7700.00 | Window Closed / Lapsed |