Patent ID: 7285984

Claim:
A programmable three input look up table (3LUT) structure adapted for carry logic implementation in an integrated circuit, comprising: a one input look up table (1LUT) structure, said input received in true and compliment levels, said 1LUT structure further comprising a first LUT value input; and a first two input look up table (2LUT) structure, said two inputs received in true and compliment levels, said 2LUT structure further comprising an output; and a first programmable multiplexer (MUX) structure comprised of: a first MUX input coupled to said first 2LUT output; and a second MUX input coupled to a carry-in logic signal; and a MUX output coupled to said first LUT value input of 1LUT; and a programmable means to couple one of said MUX inputs to the MUX output.