An arithmetic circuit is a logic circuit that performs basic arithmetic operations like addition, subtraction, increment, decrement and transfer operations using a single combinational circuit. It uses multiplexers and full adders to do so. The selection bits, along with an additional input at 2 and 3 input positions of the multiplexer, determine the type of operation to be done on the input data. This is further clarified by the function table below. As usual, a 4-bit arithmetic circuit works with 4-bit data.
Function Table for Arithmetic Circuit:
Mano, M. (n.d), Register Transfer and Micro-operations: Arithmetic Circuit, Computer System Architecture (3rd Edition), pp. 106-108