bee2-selectmap/root.v

   1 // megacz@cs.berkeley.edu,  public domain
   2
   3 module root(clk,
   4             read_empty, read_enable, read_data,
   5             write_full, write_enable, write_data);
   6
   7   input clk;
   8   input read_empty;
   9   input write_full;
  10   output read_enable;
  11   output write_enable;
  12   input  [7:0] read_data;
  13   output [7:0] write_data;
  14
  15   reg read_enable_;
  16   assign read_enable = read_enable_;
  17   reg write_enable_;
  18   assign write_enable = write_enable_;
  19   reg [7:0] write_data_;
  20   assign write_data = write_data_;
  21
  22   initial read_enable_ = 1;
  23   initial write_enable_ = 0;
  24
  25   always @(posedge clk) begin
  26
  27     // if there's stuff to read and room to write, read a byte,
  28     // increment it, and write it
  29     if (!read_enable_ && !write_enable_ && !read_empty && !write_full) begin
  30       read_enable_  <= 1;
  31       write_enable_ <= 1;
  32       write_data_   <= read_data + 1;
  33
  34     // else do nothing
  35     end else begin
  36       read_enable_  <= 0;
  37       write_enable_ <= 0;
  38
  39     end
  40
  41   end
  42
  43 endmodule