Binary Adder
The Add microoperation requires registers that can hold the data and the digital components that can perform the arithmetic addition.
A Binary Adder is a digital circuit that performs the arithmetic sum of two binary numbers provided with any length.
A Binary Adder is constructed using fulladder circuits connected in series, with the output carry from one fulladder connected to the input carry of the next fulladder.
The following block diagram shows the interconnections of four fulladder circuits to provide a 4bit binary adder.
 The augend bits (A) and the addend bits (B) are designated by subscript numbers from right to left, with subscript '0' denoting the loworder bit.
 The carry inputs starts from C0 to C3 connected in a chain through the fulladders. C4 is the resultant output carry generated by the last fulladder circuit.
 The output carry from each fulladder is connected to the input carry of the nexthighorder fulladder.
 The sum outputs (S0 to S3) generates the required arithmetic sum of augend and addend bits.
 The n data bits for the A and B inputs come from different source registers. For instance, data bits for A input comes from source register R1 and data bits for B input comes from source register R2.
 The arithmetic sum of the data inputs of A and B can be transferred to a third register or to one of the source registers (R1 or R2).
