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US 6,275,841 B1Granted
1-of-4 multiplier
AssigneeIntrinsity, Inc.
InventorsTerence M. Potter, James S. Blomgren, Anthony M. Petro
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Abstract
The described multiplier provides the signed or unsigned product of a multiplicand and multiplier represented in preferably 1-of-4 N-NARY signals by performing a preferably radix-four Booth recoding of the multiplier, producing partial products using a plurality of Booth multiplexers, summing the partial productsto produce two intermediate partial products using a six-level Wallace tree, and summing the two intermediate partial products using a carry lookahead adder. The Booth encoding is performed at the dit level using encoding circuitry implemented in N-NARY logic.
Claims24
An apparatus that provides the product of a multiplicand and a multiplier, comprising:
- an encoder circuit that performs a Booth recoding, said encoder circuit further comprises a plurality of N-NARY logic cells, each N-NARY logic cell receives an individual 1-of-N signal where N=4 that represents the value of one dit of the multiplier, each N-NARY logic cell produces an output 1-of-N signal;
- a translation buffer that converts each dit of the multiplicand into a bit pair represented by two 1-of-N signals where N=2, said translation buffer receives a plurality of 1-of-N signals where N=4 and outputs a plurality of 1-of-N signals where N=2;
- a plurality of multiplexers that produce a plurality of partial products, wherein each multiplexer receives said plurality of 1-of-N signals where N=2 and an output 1-of-N signal produced by a said encoder circuit N-NARY logic cell and produces one partial product;
- and
- an output structure comprising a Wallace tree and a final adder, said Wallace tree comprises a plurality of carry-save-adders that sum said plurality of partial products to produce two intermediate partial products, said final adder sums said two intermediate partial products to produce a final product.
2 more elements
A multiplier system that provides the product of a multiplicand and a multiplier, comprising:
- an encoder circuit that performs a Booth recoding, said encoder circuit further comprises a plurality of N-NARY logic cells, each N-NARY logic cell receives an individual 1-of-N signal where N=4 that represents the value of one dit of the multiplier, each N-NARY logic cell produces an output 1-of-N signal;
- a translation buffer that converts each dit of the multiplic and into a bit pair represented by two 1-of-N signals where N=2, said translation buffer receives a plurality of 1-of-N signals where N=4 and outputs a plurality of 1-of-N signals where N=2;
- a plurality of multiplexers that produce a plurality of partial products, wherein each multiplexer receives said plurality of 1-of-N signals where N=2 and an output 1-of-N signal produced by a said encoder circuit N-NARY logic cell and produces one partial product;
- and
- an output structure comprising a Wallace tree and a final adder, said Wallace tree comprises a plurality of carry-save-adders that sum said plurality of partial products to produce two intermediate partial products, said final adder sums said two intermediate partial products to produce a final product.
2 more elements
A method that makes an apparatus that provides the product of a multiplicand and a multiplier, comprising:
- providing a encoder circuit that performs a Booth recoding,said encoder circuit further comprises a plurality of N-NARY logic cells, each N-NARY logic cell receives an individual 1-of-N signal where N=4 that represents the value of one dit of the multiplier, each N-NARY logic cell produces an output 1-of-N signal;
- providing a translation buffer that converts each dit of the multiplicand into a bit pair represented by two 1-of-N signals where N=2, said translation buffer receives a plurality of 1-of-N signals where N=4 and outputs a plurality of 1-of-N signals where N=2;
- providing a plurality of multiplexers that produce a plurality of partial products, wherein each multiplexer receives said plurality of 1-of-N signals where N=2 and an output 1-of-N signal produced by one said encoder circuit N-NARY logic cell and produces one partial product;
- and
- providing an output structure comprising a Wallace tree and a final adder, said Wallace tree comprises a plurality of carry-save-adders that sum said plurality of partial products to produce two intermediate partial products, said final adder sums said two intermediate partial products to produce a final product.
2 more elements
A method that determines the product of a multiplicand and a multiplier, comprising:
- performing a Booth recoding of the multiplier using an encoder circuit, said encoder circuit further comprises a plurality of N-NARY logic cells, each N-NARY logic cell receives an individual 1-of-N signal where N=4 that represents the value of one dit of the multiplier, each N-NARY logic cell produces an output 1-of-N signal;
- converting each dit of the multiplicand into a bit pair represented by two 1-of-N signals where N=2,using a translation buffer that receives a plurality of 1-of-N signals where N=4 and outputs a plurality of 1-of-N signals where N=2;
- producing a plurality of partial products using a plurality of multiplexers wherein each multiplexer receives said plurality of 1-of-N signals where N=2 and an output 1-of-N signal produced by one said encoder circuit N-NARY logic cell and produces one partial product;
- producing two intermediate partial products by summing said plurality of partial products using a Wallace tree that comprises a plurality of carry-save-adders;
- and
- summing said two intermediate partial products to produce a final product.
3 more elements
Dependencies are inferred from the claim text.