Subversion Repositories srdydrdy_lib

//----------------------------------------------------------------------

//  8-bit parallel CRC generator

//----------------------------------------------------------------------

module mac_crc32

  (input         clk,

   input         clear,   // also functions as reset

   input [7:0]   data,

   input         valid,

   output [31:0] crc);

  reg [31:0]      icrc;

  reg [31:0]      nxt_icrc;

  integer        i;

  assign         crc = ~icrc;

  always @*

    begin

      nxt_icrc[7:0] = icrc[7:0] ^ data;

      nxt_icrc[31:8] = icrc[31:8];

      for (i=0; i<8; i=i+1)

        begin

          if (nxt_icrc[0])

            nxt_icrc = nxt_icrc[31:1] ^ 32'hEDB88320;

          else

            nxt_icrc = nxt_icrc[31:1];

        end

    end // always @ *

  always @(posedge clk)

    begin

      if (clear)

        icrc <= #1 {32{1'b1}};

      else if (valid)

        icrc <= nxt_icrc;

    end

endmodule