使用verilog语言生成fft代码

以下是基于Butterfly算法的verilog FFT代码示例，包含了8点FFT：

module fft (
input clk,
input rst,
input [7:0] in_data_r,
input [7:0] in_data_i,
output wire [7:0] out_data_r,
output wire [7:0] out_data_i
);

// Parameter definitions
parameter N = 8; // Number of points
parameter L = 3; // Log of N
parameter W = 8; // Wordsize in bits
parameter T = W*2; // Total data width

// Local declarations
integer i, j;

// Constants
parameter pi = 3.141592653589793;

// Internal signals
reg [T-1:0] x_r [N/2][2**L/2], x_i [N/2][2**L/2];
wire signed [W:0] w_r [2**L/2-1], w_i [2**L/2-1], w_re [2**L/2-1], w_im [2**L/2-1];
reg signed [W:0] u_r [N/2-1], u_i [N/2-1], t_r, t_i;
integer k;

// ROM for twiddle factors
// Generates sine/cosine values for each butterfly stage
generate
  for (i = 2; i <= L; i = i+1) begin : ROM
    assign w_r[i-2] = {signed{W{1'b0}}, sin(pi/2**i)};
    assign w_i[i-2] = {signed{W{1'b0}}, -sin(pi/2**i)};
    assign w_re[i-2] = {signed{W{1'b0}}, cos(pi/2**i)};
    assign w_im[i-2] = {signed{W{1'b0}}, -cos(pi/2**i)};
  end
endgenerate

// Initial data assignments
assign x_r[0][0] = {in_data_r, 0};
assign x_i[0][0] = {in_data_i, 0};

// Butterfly operations
generate
  for (i = 2; i <= L; i = i+1) begin : Butterfly
    generate
      for (j = 0; j < 2**(i-2); j = j+1) begin : Stage
        assign u_r[j] = x_r[i-2][2*j] + x_r[i-2][2*j+1]; // Butterfly input
        assign u_i[j] = x_i[i-2][2*j] + x_i[i-2][2*j+1];

        // Twiddle factor multiplication
        generate
          for (k = 0; k < 2**(L-i); k = k+1) begin : Multiply
            always @* begin
              if (k == 0) begin
                t_r = w_r[i-2]*x_r[i-2][2*j+1] - w_i[i-2]*x_i[i-2][2*j+1];
                t_i = w_re[i-2]*x_i[i-2][2*j+1] + w_im[i-2]*x_r[i-2][2*j+1];
              end else begin
                t_r = w_r[i-2]*u_r[k-1] - w_i[i-2]*u_i[k-1];
                t_i = w_re[i-2]*u_i[k-1] + w_im[i-2]*u_r[k-1];
              end
            end
            assign x_r[i-1][2*j+k] = u_r[j] + t_r; // Butterfly output
            assign x_i[i-1][2*j+k] = u_i[j] + t_i;
          end
        endgenerate
      end
    endgenerate
  end
endgenerate

// Final output assignments
assign out_data_r = x_r[L-1][0][7:0]; // Real component of output data
assign out_data_i = x_i[L-1][0][7:0]; // Imaginary component of output data

endmodule