Digital electronic adder and subtractor unit - has inputs received by registers coupled to separate adder and subtractor units controlled by circuit with two counters

摘要

The digital electronic circuit for addition and subtraction of two coded numbers has input shift registers that connect with the inputs of an adder circuit and a separate subtractor circuit. Each of the circuits receives two four digit code values. Outputs from the adder and subtractor are selectively received by a register. The circuitry operates with signals generated by a control circuit (30) that receives inputs from function selectors. The circuit consists of pulse counters (28,29), a pair of flip-flops (31,32) and some logic gates. ADVANTAGE - Simplified control of circuit.