module alu_decoder (
input [1:0] opcode,
output reg [3:0] alu_op
);
always @* begin
case (opcode)
// Write solution here
'b00: alu_op = 'b0001;
'b01: alu_op = 'b0010;
'b10: alu_op = 'b0100;
'b11: alu_op = 'b1000;
default: alu_op = 0;
endcase
end
endmodule