module TwoPButterfly( input wire en, input wire clk, input wire [63:0]inr1,ini1,inr2,ini2,
								output reg [63:0]outr1,outi1,outr2,outi2);

add_sub adder1(en,clk,inr1[63],inr2[63],inr1[62:52],inr2[62:52],inr1[51:0],inr2[51:0],1'b0,outr1[63],outr1[62:52],outr1[51:0]);
add_sub adder2(en,clk,ini1[63],ini2[63],ini1[62:52],ini2[62:52],ini1[51:0],ini2[51:0],1'b0,outi1[63],outi1[62:52],outi1[51:0]);

add_sub subtractor1(en,clk,inr1[63],inr2[63],inr1[62:52],inr2[62:52],inr1[51:0],inr2[51:0],1'b1,outr2[63],outr2[62:52],outr2[51:0]);
add_sub subtractor2(en,clk,ini1[63],ini2[63],ini1[62:52],ini2[62:52],ini1[51:0],ini2[51:0],1'b1,outi2[63],outi2[62:52],outi2[51:0]);

endmodule

----------------------------
module add_sub(input wire en, input wire clk, input wire S1,S2,
               input wire[10:0]E1, input wire [10:0]E2,
               input wire[51:0]F1,input wire [51:0]F2,
                    input wire aors,
                             output reg S,output reg[10:0]E,output reg[51:0]F);
....
....// ieee - 754 format adder/subtractor code which is working fine
....

endmodule

---------------------------
//testbench

module TwoPButterfly_tb;

reg en,clk;
reg [63:0]inr1,ini1,inr2,ini2;
wire [63:0]outr1,outi1,outr2,outi2;

TwoPButterfly T1(en,clk,inr1,ini1,inr2,ini2,outr1,outi1,outr2,outi2);
always #5 clk <= ~clk;

initial
begin
    clk = 1'b0;
    en = 1'b1;

    #4
    // 7+7i , 6+6i
    inr1 <= 64'b0100000000011100000000000000000000000000000000000000000000000000;
    ini1 <= 64'b0100000000011100000000000000000000000000000000000000000000000000;
    inr2 <= 64'b0100000000011000000000000000000000000000000000000000000000000000;
    ini2 <= 64'b0100000000011000000000000000000000000000000000000000000000000000;
end
endmodule