Combined adder and pre-adder for high-radix multiplier circuit
First Claim
1. Circuitry accepting a first input value and a second input value and outputting (a) a first sum involving said first input value and said second input value, and (b) a second sum involving said first input value and said second input value, said circuitry comprising:
- a first adder circuit;
a second adder circuit;
a compressor circuit; and
a preprocessing stage;
wherein;
said first input value and said second input value are input to said first adder circuit to provide said first sum;
said first input value and said second input value are input to said preprocessing stage to provide inputs to said compressor circuit, said compressor circuit providing first and second compressed output signals;
said first and second compressed output signals are input to said second adder circuit to provide said second sum.
1 Assignment
0 Petitions
Accused Products
Abstract
Circuitry accepting a first input value and a second input value, and outputting (a) a first sum involving the first input value and the second input value, and (b) a second sum involving the first input value and the second input value, includes a first adder circuit, a second adder circuit, a compressor circuit and a preprocessing stage. The first input value and the second input value are input to the first adder circuit to provide the first sum. The first input value and the second input value are input to the preprocessing stage to provide inputs to the compressor circuit, which provides first and second compressed output signals which in turn are input to the second adder circuit to provide the second sum. The preprocessing stage may include circuitry to programmably zero the first input value, so that the first sum is programmably settable to the second input value.
400 Citations
21 Claims
-
1. Circuitry accepting a first input value and a second input value and outputting (a) a first sum involving said first input value and said second input value, and (b) a second sum involving said first input value and said second input value, said circuitry comprising:
-
a first adder circuit; a second adder circuit; a compressor circuit; and a preprocessing stage;
wherein;said first input value and said second input value are input to said first adder circuit to provide said first sum; said first input value and said second input value are input to said preprocessing stage to provide inputs to said compressor circuit, said compressor circuit providing first and second compressed output signals; said first and second compressed output signals are input to said second adder circuit to provide said second sum. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
-
-
10. Adder circuitry for two input values, wherein one of said two input values being twice another of said two input values, said adder circuitry comprising:
-
respective input exclusive OR gates for each bit position, each respective input exclusive OR gate having as inputs respective bits of said two input values; a prefix tree having as inputs respective bits of said two input values, and providing as outputs respective carry values for each bit position; and respective output exclusive OR gates for each bit position, each respective output exclusive OR gate having as inputs said respective carry value for said respective bit position, and said output of said respective input exclusive OR gate;
wherein;said prefix tree is customized by constructing an initial level of said prefix tree based on each respective bit of said one of said two input values being identical to a respective next-less-significant bit of said another of said two input values. - View Dependent Claims (11, 12)
-
-
13. Circuitry accepting a first input value at a first input port and a second input value at a second input port and outputting (a) a first sum involving said first input value and said second input value, and (b) a second sum involving said first input value and said second input value, said circuitry comprising:
-
a first adder circuit; a second adder circuit; a compressor circuit coupled to said second adder circuit; and a preprocessing stage coupled between said first and second input ports, said compressor circuit, and said first adder circuit, wherein said preprocessing stage comprises circuitry to programmably zero said first input value;
whereby;said first sum is programmably settable to said second input value and said second sum is programmable to be independent of said first input value. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21)
-
Specification