UVM/vmm-1.1.1a/shared/examples/syn_tb_fifo/dut.v

// 
// -------------------------------------------------------------
//    Copyright 2004-2008 Synopsys, Inc.
//    All Rights Reserved Worldwide
// 
//    Licensed under the Apache License, Version 2.0 (the
//    "License"); you may not use this file except in
//    compliance with the License.  You may obtain a copy of
//    the License at
// 
//        http://www.apache.org/licenses/LICENSE-2.0
// 
//    Unless required by applicable law or agreed to in
//    writing, software distributed under the License is
//    distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
//    CONDITIONS OF ANY KIND, either express or implied.  See
//    the License for the specific language governing
//    permissions and limitations under the License.
// -------------------------------------------------------------
// 

//
// DUT: Sync WR, Async RD 128x16-bot FIFO
//

module dut (clk, rst, push_req_n, pop_req_n, data_in, data_out);

input         clk;
input         rst;
input         push_req_n;
input         pop_req_n;
input  [15:0] data_in;
output [15:0] data_out;

reg [15:0] FIFO[127:0];
reg [ 6:0] wr_ptr;
reg [ 6:0] rd_ptr;

assign  data_out = FIFO[rd_ptr];

always @(posedge clk)
begin
   if (rst) begin
      wr_ptr <= 0;
      rd_ptr <= 0;
   end
   else begin
      if (push_req_n == 0) begin
         FIFO[wr_ptr] <= data_in;
         wr_ptr       <= wr_ptr + 1;
      end
      if (pop_req_n == 0) begin
         rd_ptr       <= rd_ptr + 1;
      end
   end
end

endmodule