Basic Addition Review Basic Adders and the Carry Problem Carry Propagation Speedup Speed/Cost Tradeoffs Two-operand Versus Multi-operand Adders
Half Adders
Adder Equations
Full Adder F (A,B,C) = A B C G = AB + AC + BC AB S CiCo Cin AB Cout Sum Sum = A B Cin Cout = AB + Cin A + Cin B = AB + Cin (A + B) Full Adder (FA)
4-Bit Ripple Carry Adder AB S CiCo AB S CiCo AB S CiCo AB S CiCo Cin A(0) Cout B(0)A(1)B(1)A(2)B(2)A(3)B(3) C(0)C(1)C(2)C(3)C(4) Sum(0)Sum(1)Sum(2)Sum(3) A[3:0] B[3:0] SUM[3:0] + C[0] C[4]
Full Adder Implementations
Adder Circuits Using FA
Ripple Carry Adder Layout
Delay in Ripple Adder
Adders as Logic Elements
Adder Exceptions
Adder Exception Circuitry
Carry Propagation Analysis
Carry Completion Detection
Counters
Asynchronous up-Counter
Three-stage up-Counter
Generate, Propagate and Kill
Transfer Signal
Manchester Carry Chain