Untitled

full adder
module FullAdder(SUM, CARRY, A, B, C);
input A,B,C;
output SUM,CARRY;
wire W1, W2, W3;
xor g1(W1,A,B);
xor g2(SUM,W1,C);
and g3(W2,A,B);
and g4(W3,W1,C);
or g5(CARRY,W2,W3);
endmodule

full adder
module FullAdder_4bit(S,Cout,A,B);
input[3:0]A;
input[3:0]B;
output[3:0]S;
output Cout;
wire[3:1]C;
FullAdder FA0(S[0],C[1],A[0],B[0],1'b0);
FullAdder FA1(S[1],C[2],A[1],B[1],C[1]);
FullAdder FA2(S[2],C[3],A[2],B[2],C[2]);
FullAdder FA3(S[3],Cout,A[3],B[3],C[3]);
endmodule


test bench
module tb_adder_4bit;
reg[3:0]A;
reg[3:0]B;
wire[3:0]S;
wire Cout;
adder_4bit uut(.S(S),.Cout(Cout),.A(A),.B(B));
initial begin
     A=5;  B=5;
#100 A=15; B=12;
end
endmodule

8 bit ALU
module alu(A,B,ALU_Sel,ALU_Result);
input[7:0]A;
input[7:0]B;
input[3:0]ALU_Sel;
output[7:0]ALU_Result;
reg[7:0]ALU_Result;
always@(*)
begin
case(ALU_Sel)
4'b0000:ALU_Result=A+1;
4'b0001:ALU_Result=A+B;
4'b0010:ALU_Result=A-1;
4'b0011:ALU_Result=A-B;
4'b0100:ALU_Result=A*B;
4'b0101:ALU_Result=A==B;
4'b0110:ALU_Result=A>B;
4'b0111:ALU_Result=A<B;
4'b1000:ALU_Result=~A;
4'b1001:ALU_Result=A&B;
4'b1010:ALU_Result=A|B;
4'b1011:ALU_Result=~(A&B);
4'b1100:ALU_Result=~(A|B);
4'b1101:ALU_Result=A^B;
4'b1110:ALU_Result=A>>1;
4'b111:ALU_Result=A<<1;
endcase
end
endmodule

testhbench
module alu_tb;
reg[7:0]A,B;
reg[3:0]ALU_Sel;
wire[7:0]ALU_Result;
alu uut(.A(A),.B(B),.ALU_Sel(ALU_Sel),.ALU_Result(ALU_Result));
initial
begin
#100 A=8'b10101111; B=8'b01001011;
ALU_Sel=4'b0000;
#100 A=8'b10101111; B=8'b01001011;
ALU_Sel=4'b0001;
#100 A=8'b10101111; B=8'b01001011;
ALU_Sel=4'b0010;
#100 A=8'b10101111; B=8'b01001011;
ALU_Sel=4'b0011;
#100 A=8'b10101111; B=8'b01001011;
ALU_Sel=4'b0100;
#100 A=8'b10101111; B=8'b01001011;
ALU_Sel=4'b0101;
#100 A=8'b10101111; B=8'b01001011;
ALU_Sel=4'b0110;
#100 A=8'b10101111; B=8'b01001011;
ALU_Sel=4'b0111;
#100 A=8'b10101111; B=8'b01001011;
ALU_Sel=4'b1000;
#100 A=8'b10101111; B=8'b01001011;
ALU_Sel=4'b1001;
#100 A=8'b10101111; B=8'b01001011;
ALU_Sel=4'b1010;
#100 A=8'b10101111; B=8'b01001011;
ALU_Sel=4'b1011;
#100 A=8'b10101111; B=8'b01001011;
ALU_Sel=4'b1100;
#100 A=8'b10101111; B=8'b01001011;
ALU_Sel=4'b1101;
#100 A=8'b10101111; B=8'b01001011;
ALU_Sel=4'b1110;
#100 A=8'b10101111; B=8'b01001011;
ALU_Sel=4'b1111;
end
endmodule