6. Write a VHDL code to implement the 4-bit ALU using CASE statement. A and B are two 4-bit inputs to the ALU, and Y is the output. The opcode formed by S1 and S0 controls the ALU functions as shown in Table. s1 s0 Operation Name Operation 0 0 Pass Pass A to output 0 1 OR A OR B 1 0 Increment A+1 1 1 Addition A + B