Look-up table structure with embedded carry logic
AssigneeViciciv Technology
InventorRaminda Madurawe
Life of this patent
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Abstract
A multiple input look up table (LUT) structure adapted for carry-logic implementation, wherein each input is received in true and compliment levels, comprising: an output of an intermediate stage within the LUT structure; and a LUT value input of a stage next to said intermediate stage; and a multiplexer (MUX) structure coupled between the output and the LUT value input, wherein the MUX structure further comprises: a plurality of secondary inputs, including a carry-in logic signal; and a configuration circuit to couple one of the output or a said secondary input to said LUT value input.
Claims20
A programmable four input look up table (4LUT) 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 three input look up table (3LUT) structure, said three inputs received in true and compliment levels, said 3LUT structure further comprising an output;
- and
- a first programmable multiplexer (MUX) structure comprised of:
- a plurality of MUX inputs, one of the MUX inputs coupled to said first 3LUT output, and one of the MUX inputs coupled to a carry-in signal;
- and
- a MUX output, said output coupled to said first LUT value input;
- and
- a programmable means for said first 3LUT output to couple to said 1LUT input, and for one of the first MUX inputs to couple to said first LUT value input.
A programmable multi input macro look up table structure adapted for carry logic implementation in an integrated circuit, comprising:
- a first multi input look up table (first LUT) structure, said inputs received in true and compliment levels, said first LUT structure further comprised of a first LUT value input;
- and
- a second multi input look up table (second LUT) structure, said inputs received in true and compliment levels, said second LUT structure further comprising an output;
- and
- a first programmable multiplexer (MUX) structure comprised of:
- a plurality of MUX inputs, one of the MUX inputs coupled to said second LUT output, and one of the MUX inputs coupled to a carry-in signal;
- and
- a MUX output, said output coupled to said first LUT value input;
- and
- a programmable means for said second LUT output to couple to one of said first LUT inputs, and for one of the first MUX inputs to couple to said first LUT value input.
A multiple input look up table (LUT) structure wherein each input is received in true and compliment levels, comprising:
- an output of an intermediate stage within the LUT structure;
- and
- a LUT value input of a stage next to said intermediate stage;
- and
- a multiplexer (MUX) structure coupled between the output and the LUT value input, wherein the MUX structure further comprises:
- a plurality of secondary inputs, including a carry-in logic signal;
- and
- a configuration circuit to couple one of the output or a said secondary input to said LUT value input.
Dependencies are inferred from the claim text.