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Codiode/Problems/Combinational Logic

Implement a Full Adder Sum and Carry Using Two 4:1 MUXes

HardLogic CircuitBuild

Arithmetic logic units often synthesize complex Boolean functions using multiplexers to optimize for specific FPGA architectures or standard cell libraries. A full adder can be decomposed into two independent routing functions driven by shared select lines.

Implement the sum and carry-out logic of a full adder.

| A | B | Cin | Sum | Cout | |-----|-----|-------|-------|--------| | 0 | 0 | 0 | 0 | 0 | | 0 | 0 | 1 | 1 | 0 | | 0 | 1 | 0 | 1 | 0 | | 0 | 1 | 1 | 0 | 1 | | 1 | 0 | 0 | 1 | 0 | | 1 | 0 | 1 | 0 | 1 | | 1 | 1 | 0 | 0 | 1 | | 1 | 1 | 1 | 1 | 1 |

Constraints

  • Use exactly two 4:1 multiplexers.
  • Connect A and B to the select lines of both multiplexers.
  • Drive the multiplexer data inputs using only Cin, an inverted Cin, or constant logic values.
  • Use at most one NOT gate.
  • Do not use any AND, OR, NAND, NOR, or XOR gates.

Topics

addermultiplexerlogic-synthesis

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