SHA256 算法，verilog

以下是SHA256算法的Verilog代码示例：

module sha256 (
  input wire clk,
  input wire rst,
  input wire [511:0] msg,
  output reg [255:0] hash
);

  reg [31:0] w[63:0];
  reg [7:0] temp[63:0];
  reg [31:0] a, b, c, d, e, f, g, h;
  reg [31:0] t1, t2;

  always @ (posedge clk or posedge rst) begin
    if (rst) begin
      a <= 32'h6a09e667;
      b <= 32'hbb67ae85;
      c <= 32'h3c6ef372;
      d <= 32'ha54ff53a;
      e <= 32'h510e527f;
      f <= 32'h9b05688c;
      g <= 32'h1f83d9ab;
      h <= 32'h5be0cd19;
    end else begin
      for (i = 0; i < 16; i = i + 1) begin
        w[i] <= msg[i*32+31:i*32];
      end
      for (i = 16; i < 64; i = i + 1) begin
        w[i] <= w[i-16] + w[i-7] + (w[i-15] >> 7) + (w[i-2] >> 17);
      end
      a <= h;
      b <= g;
      c <= f;
      d <= e;
      e <= d + t1;
      f <= c;
      g <= b;
      h <= a;

      for (i = 0; i < 64; i = i + 1) begin
        t1 <= h + ((e >> 6) ^ (e >> 11) ^ (e >> 25)) + ((e & f) ^ (~e & g)) + k[i] + w[i];
        t2 <= ((a >> 2) ^ (a >> 13) ^ (a >> 22)) + ((a & b) ^ (a & c) ^ (b & c));
        h <= g;
        g <= f;
        f <= e;
        e <= d + t1;
        d <= c;
        c <= b;
        b <= a;
        a <= t1 + t2;
      end
      hash <= {a, b, c, d, e, f, g, h};
    end
  end

  parameter [31:0] k[63:0] = '{
    32'h428a2f98, 32'h71374491, 32'hb5c0fbcf, 32'he9b5dba5,
    32'h3956c25b, 32'h59f111f1, 32'h923f82a4, 32'hab1c5ed5,
    32'hd807aa98, 32'h12835b01, 32'h243185be, 32'h550c7dc3,
    32'h72be5d74, 32'h80deb1fe, 32'heb86d391, 32'h9bdc06a7,
    32'hc19bf174, 32'he49b69c1, 32'hefbe4786, 32'h0fc19dc6,
    32'h240ca1cc, 32'h2de92c6f, 32'h4a7484aa, 32'h5cb0a9dc,
    32'h76f988da, 32'h983e5152, 32'ha831c66d, 32'hb00327c8,
    32'hbf597fc7, 32'hc6e00bf3, 32'hd5a79147, 32'h06ca6351,
    32'h14292967, 32'h27b70a85, 32'h2e1b2138, 32'h4d2c6dfc,
    32'h53380d13, 32'h650a7354, 32'h766a0abb, 32'h81c2c92e,
    32'h92722c85, 32'ha2bfe8a1, 32'ha81a664b, 32'hc24b8b70,
    32'hc76c51a3, 32'hd192e819, 32'hd6990624, 32'hf40e3585,
    32'h106aa070, 32'h19a4c116, 32'h1e376c08, 32'h2748774c,
    32'h34b0bcb5, 32'h391c0cb3, 32'h4ed8aa4a, 32'h5b9cca4f,
    32'h682e6ff3, 32'h748f82ee, 32'h78a5636f, 32'h84c87814,
    32'h8cc70208, 32'h90befffa, 32'ha4506ceb, 32'hbef9a3f7,
    32'hc67178f2
  };

endmodule