uhd

//

// Copyright 2011 Ettus Research LLC

//

// This program is free software: you can redistribute it and/or modify

// it under the terms of the GNU General Public License as published by

// the Free Software Foundation, either version 3 of the License, or

// (at your option) any later version.

//

// This program is distributed in the hope that it will be useful,

// but WITHOUT ANY WARRANTY; without even the implied warranty of

// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

// GNU General Public License for more details.

//

// You should have received a copy of the GNU General Public License

// along with this program.  If not, see <http://www.gnu.org/licenses/>.

//

module medfifo

  #(parameter WIDTH=32,

    parameter DEPTH=1)

    (input clk, input rst,

     input [WIDTH-1:0] datain,

     output [WIDTH-1:0] dataout,

     input read,

     input write,

     input clear,

     output full,

     output empty,

     output [7:0] space,

     output [7:0] occupied);

   localparam 		NUM_FIFOS = (1<<DEPTH);

   wire [WIDTH-1:0] 	dout [0:NUM_FIFOS-1];

   wire [0:NUM_FIFOS-1] full_x;

   wire [0:NUM_FIFOS-1] empty_x;

   shortfifo #(.WIDTH(WIDTH))

     head (.clk(clk),.rst(rst),

	   .datain(datain),.write(write),.full(full),

	   .dataout(dout[0]),.read(~empty_x[0] & ~full_x[1]),.empty(empty_x[0]),

	   .clear(clear),.space(space[4:0]),.occupied() );

   shortfifo #(.WIDTH(WIDTH))

     tail (.clk(clk),.rst(rst),

	   .datain(dout[NUM_FIFOS-2]),.write(~empty_x[NUM_FIFOS-2] & ~full_x[NUM_FIFOS-1]),.full(full_x[NUM_FIFOS-1]),

	   .dataout(dataout),.read(read),.empty(empty),

	   .clear(clear),.space(),.occupied(occupied[4:0]) );

   genvar 		i;

   generate

      for(i = 1; i < NUM_FIFOS-1 ; i = i + 1)

	begin : gen_depth

	   shortfifo #(.WIDTH(WIDTH))

	     shortfifo (.clk(clk),.rst(rst),

			.datain(dout[i-1]),.write(~full_x[i] & ~empty_x[i-1]),.full(full_x[i]),

			.dataout(dout[i]),.read(~full_x[i+1] & ~empty_x[i]),.empty(empty_x[i]),

			.clear(clear),.space(),.occupied() );

	end

   endgenerate

   assign space[7:5] = 0;

   assign occupied[7:5] = 0;

endmodule // medfifo