module main#(parameter n = 8)(output reg[64*n-1:0] out,input[64*n-1:0] in1,input[64*n-1:0] in2);

  wire [64*n-1:0] out_wire;
  wire [64*n-1:0] out1;
  wire [64*n-1:0] out2;
  reg  [64*n-1:0] Temp;
  genvar i;

  butterfly#(n)bt1(out1,in1);
  butterfly#(n)bt2(out2,in2);
  function [63:0] mul;

  input [63:0] in1;
  input [63:0] in2;
  reg [127:0] out;

  begin
  out[127:64]= in1[31:0]*in2[31:0]-in1[63:32]*in2[63:32];
  out[63:0]= in1[31:0]*in2[63:32]+in2[31:0]*in1[63:32];

  mul[63:32] = out[105:74]; //real
  mul[31:0] = out[41:10]; // complex
  end

  endfunction

  generate
    for(i=0;i<n;i=i+1)
    begin
      always@(out1 or out2)
      begin
      Temp = Temp>>64;
    Temp[64*n-1:64*n-64] = mul(out1[64*(i+1)-1:64*i], out2[64*(i+1)-1:64*i]);
   end
    end
endgenerate

  ibutterfly#(n)(out_wire,Temp);

  always@(out_wire)
  out = out_wire;
endmodule

    module butterfly#(parameter n = 8)(output reg[64*n-1:0] out,input[64*n-1:0] in);

      //parameter n = 8;
      integer i ;
       genvar j;

      reg [32*n-1:0] in_odd;
      reg [32*n-1:0] in_even;

     // reg [32*n-1:0] out_odd ;
     // reg [32*n-1:0] out_even;

      wire [32*n-1:0] out_odd_wire ;
      wire [32*n-1:0] out_even_wire;

      reg [64*n-1:0] tmp_in ;


      always@(in or n)
      begin

       tmp_in = in;

        for(i=0;i<n/2;i=i+1)
      begin

        in_odd = in_odd>>64;
        in_even = in_even>>64;

        in_even[32*n-1:32*n-64] =  tmp_in[63:0];
        in_odd[32*n-1:32*n-64] = tmp_in[127:64];
        tmp_in = tmp_in>>128;

      end

    end

    generate
    if(n>1)
    begin
      butterfly#(n/2) but1(out_odd_wire,in_odd);
      butterfly#(n/2) but2(out_even_wire,in_even);
      initial
      $display("%d n is n",n);
     for(j=0;j<n/2;j=j+1)
      begin

        always@(out_even_wire or out_even_wire)
        begin
          out = out >> 64;
          $display("%d is the angel",j);
          out[64*n-1:64*n-64] = add(out_even_wire[64*(j+1)-1:64*j], mul(cordic(360*j/n),out_odd_wire[64*(j+1)-1:64*j]));
          out[32*n-1:32*n-64] =  sub(out_even_wire[64*(j+1)-1:64*j] , mul(cordic(360*j/n),out_odd_wire[64*(j+1)-1:64*j]));
        end
      end
    end
    else if(n==1)
      always@(in)
      begin
        $display("%d n is n",n);
        out = in;
      end
    endgenerate

    function [63:0] add;

      input [63:0] in1;
      input [63:0] in2;
      begin
        add[63:32] = in1[63:32]+in2[63:32];
        add[31:0] = in1[31:0]+in2[31:0];
      end
    endfunction

    function [63:0] sub;

      input [63:0] in1;
      input [63:0] in2;
      begin
        sub[63:32] = in1[63:32]-in2[63:32];
        sub[31:0] = in1[31:0]-in2[31:0];
      end
    endfunction

    function [63:0] mul;

      input [63:0] in1;
      input [63:0] in2;
      reg [127:0] out;

      begin
      out[127:64]= in1[31:0]*in2[31:0]-in1[63:32]*in2[63:32];
      out[63:0]= in1[31:0]*in2[63:32]+in2[31:0]*in1[63:32];

      mul[63:32] = out[105:74]; //real
      mul[31:0] = out[41:10]; // complex
      end

      endfunction

      function [63:0] cordic;
      input [31:0] A;
      reg [31:0] sin,cos;

      integer signed x, y, z,x1,y1;
      integer AT[19:0];
      integer a,i;
      begin
        AT[0] = 2949120;
        AT[1] = 1740967;
        AT[2] = 919879;
        AT[3] = 466945;
        AT[4] = 234378;
        AT[5] = 117303;
        AT[6] = 58666;
        AT[7] = 29334;
        AT[8] = 14667;
        AT[9] = 7333;
        AT[10] = 3666;
        AT[11] = 1833;
        AT[12] = 916;
        AT[13] = 458;
        AT[14] = 229;
        AT[15] = 114;
        AT[16] = 57;
        AT[17] = 28;
        AT[18] = 14;
        AT[19] = 7;

        i = 0;
        a = A << 16;
        x = 39796;
        z = 0;
        y = 0;
        for(i=0;i<20;i=i+1)
        begin
          if(z > a)
          begin
            x1 = x - (y >>> i);
            y1 = y + (x >>> i);
            z = z - AT[i];
          end
          else
          begin
           x1 = x + (y >>> i);
           y1 = y - (x >>> i);
           z = z + AT[i];
          end
          x = x1;
          y = y1;
         end
         sin = y[31] ? -y : y;
         cos = x[31] ? -x : x;
         cordic[41:32] = cos[15:4];
         cordic[63:60] = 0;
         cordic[59:42] = cos[31:16];
         cordic[9:0] = sin[15:4];
         cordic[25:10] = sin[31:16];
         cordic[31:26] = 0;
         end
      endfunction


    endmodule

        module ibutterfly#(parameter n = 8)(output reg[64*n-1:0] out,input[64*n-1:0] in);

      //parameter n = 8;
      integer i ;
       genvar j;

       reg [31:0] shift;
       reg [31:0] log_in = n;

      reg [32*n-1:0] in_odd;
      reg [32*n-1:0] in_even;

     // reg [32*n-1:0] out_odd ;
     // reg [32*n-1:0] out_even;

      wire [32*n-1:0] out_odd_wire ;
      wire [32*n-1:0] out_even_wire;

      reg [64*n-1:0] tmp_in ;


      always@(in or n)
      begin

       tmp_in = in;

        for(i=0;i<n/2;i=i+1)
      begin

        in_odd = in_odd>>64;
        in_even = in_even>>64;

        in_even[32*n-1:32*n-64] =  tmp_in[63:0];
        in_odd[32*n-1:32*n-64] = tmp_in[127:64];
        tmp_in = tmp_in>>128;

      end

    end

    generate
    if(n>1)
    begin
      ibutterfly#(n/2) ibut1(out_odd_wire,in_odd);
      ibutterfly#(n/2) ibut2(out_even_wire,in_even);
      initial
      $display("%d n is n",n);
     for(j=0;j<n/2;j=j+1)
      begin

        always@(out_even_wire or out_even_wire)
        begin
          shift = log(log_in);
          out = out >> 64;
          $display("%d is the angel",j);
          out[64*n-1:64*n-64] = sub(out_even_wire[64*(j+1)-1:64*j], mul(cordic(360*j/n),out_odd_wire[64*(j+1)-1:64*j]));
          out[32*n-1:32*n-64] =  add(out_even_wire[64*(j+1)-1:64*j] , mul(cordic(360*j/n),out_odd_wire[64*(j+1)-1:64*j]));
          out[64*n-1:64*n-32] = out[64*n-1:64*n-32]>>shift;
          out[64*n-33:64*n-64] = out[64*n-33:64*n-64]>>shift;
          out[32*n-1:32*n-32] = out[32*n-1:32*n-32]>>shift;
          out[32*n-33:32*n-64] = out[32*n-33:32*n-64]>>shift;
        end
      end
    end
    else if(n==1)
      always@(in)
      begin
        $display("%d n is n",n);
        out = in;
      end
    endgenerate

    function [31:0] log;
      input [31:0] in;
      integer i;
      reg counter;
      begin
        counter = 0;
        for(i=0;i<32;i=i+1)
        begin
          if(in!=0)
            counter = counter+1;
            in = in>>1;
        end
        log = counter;
      end
    endfunction


    function [63:0] add;

      input [63:0] in1;
      input [63:0] in2;
      begin
        add[63:32] = in1[63:32]+in2[63:32];
        add[31:0] = in1[31:0]+in2[31:0];
      end
    endfunction

    function [63:0] sub;

      input [63:0] in1;
      input [63:0] in2;
      begin
        sub[63:32] = in1[63:32]-in2[63:32];
        sub[31:0] = in1[31:0]-in2[31:0];
      end
    endfunction

    function [63:0] mul;

      input [63:0] in1;
      input [63:0] in2;
      reg [127:0] out;

      begin
      out[127:64]= in1[31:0]*in2[31:0]-in1[63:32]*in2[63:32];
      out[63:0]= in1[31:0]*in2[63:32]+in2[31:0]*in1[63:32];

      mul[63:32] = out[105:74]; //real
      mul[31:0] = out[41:10]; // complex
      end

      endfunction

      function [63:0] cordic;
      input [31:0] A;
      reg [31:0] sin,cos;

      integer signed x, y, z,x1,y1;
      integer AT[19:0];
      integer a,i;
      begin
        AT[0] = 2949120;
        AT[1] = 1740967;
        AT[2] = 919879;
        AT[3] = 466945;
        AT[4] = 234378;
        AT[5] = 117303;
        AT[6] = 58666;
        AT[7] = 29334;
        AT[8] = 14667;
        AT[9] = 7333;
        AT[10] = 3666;
        AT[11] = 1833;
        AT[12] = 916;
        AT[13] = 458;
        AT[14] = 229;
        AT[15] = 114;
        AT[16] = 57;
        AT[17] = 28;
        AT[18] = 14;
        AT[19] = 7;

        i = 0;
        a = A << 16;
        x = 39796;
        z = 0;
        y = 0;
        for(i=0;i<20;i=i+1)
        begin
          if(z > a)
          begin
            x1 = x - (y >>> i);
            y1 = y + (x >>> i);
            z = z - AT[i];
          end
          else
          begin
           x1 = x + (y >>> i);
           y1 = y - (x >>> i);
           z = z + AT[i];
          end
          x = x1;
          y = y1;
         end
         sin = y[31] ? -y : y;
         cos = x[31] ? -x : x;
         cordic[41:32] = cos[15:4];
         cordic[63:60] = 0;
         cordic[59:42] = cos[31:16];
         cordic[9:0] = sin[15:4];
         cordic[25:10] = sin[31:16];
         cordic[31:26] = 0;
         end
      endfunction


    endmodule

     module test;
     reg [64*8-1:0] in;
     wire [64*8-1:0] out;
     butterfly #(8)b(out,in);
     initial
     begin
       in = 256'd0;
       #10
      in = 512'd565833983613456589907598696096983653424;
     end
     endmodule