0. Datapath

   To make the calculator work, you have to create datapath components for the Datapath subcircuit:

   1. Create an ALU that can calculate the result for the basic arithmetic operations (addition, subtraction, multiplication, division) for two 8-bit values. The ALU should output the needed result depending on the selected operation.

   2. Use 3 registers to store the first number, selected operator and second number. Remember that registers store the values on the input during a rising edge in the clock input (default setting in Logisim) and while they are enabled (enable input high).

   3. Use a multiplexer to select the correct display value based on the output of the calculator display controller circuit.