1. Design a 4-bit ALU that performs Arithmetic (add, subtraction), and Logic operations (AND, OR). The following control signals are to be considered: A/S: add/subtract (0:add, 1:subtract) A/O: and/or (0:and, 1:0) A/L: arithmetic/Logic (0:arithmetic, 1:logic) R/W: read/write signal (0:read, 1:write) 2. Simulate your design. Unit 1 - Design a 4-bit adder/subtractor that accepts two 4-bits numbers, A and B, and either add them up (A + B) or subtract them (A - B) depending on a control signal A/S (when the control signal is o perform ADD, otherwise if the signal is 1 then perform SUB). The result will be stored in C. Unit 2 - Design a 4-bit AND/OR unit that accepts two 4-bits numbers, A and B, and either AND them or OR them depending on a control signal A/O (when the control signal is o perform AND, otherwise if the signal is 1 then perform OR - bitwise logical operation). The result will be stored in C. Unit 3 - Design a 4-bit ALU using Unit 1 and Unit 2. The control signal A/L will indicate which operation the ALU will perform (when the control signal is o perform Arithmetic, otherwise if the signal is 1 then perform Logic). Unit 4 - Design three 4-bit parallel registers to hold A, B, and C where C keeps the output of the ALU. The registers have a RAW control signal that indicates that they are being written to or read from