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Write a $4$ bit ripple adder that uses instances of this fulladder FA shown below, A and B are inputs, Cin is thecarry in$,$ Sum is the output sum, Cout is the carry out, and OF indicates overflow which is determined by the$($carryin to the last bit$)$ xor $($the carry out$)$

module FA$($ input A$,$ B$,$ Cin, output C$,$ Cout $)$;

assign C $=($A$^$B$)^$Cin;

assign Cout $=$ A&B $|$ A&Cin $|$ B&Cin;

endmodule

$//$ this is you $4$ bit ripple adder, fill in your code using instances of FA

module FA$4($input $[3$:$0]$ A$,$ B$,$ input Cin, output $[3$:$0]$ Sum, output Cout, OF $)$;

Then, Write a $4$:$1$ multiplexer module with $4$ bit inputs A$,$ B$,$ C$,$ D$,$ a select S$,$ and $4$ bit output F$.$

And finally, Use an instance of this multiplexer and the ripple adder to make a $4$ bit ALU module. The ALU should do additionusing the ripple adder you wrote, subtraction using a $2$s compliment and the ripple adder you wrote, multiplyusing $*,$ and divide using $/.$ This will require multiple instances of the ripple adder you wote.

ALU inputs should be $4-$bit A$,$ B$,2-$bit opcode, and output should be $4-$bit result. Cout and OF will be local andnot outputs of the ALU. The select bits of the multiplexer should be opcodes for each, so $2$b$00$ should be add,$2$b$01$ should be subtract, $2$b$10$ should be multiply, and $2$b$11$ should be divide.