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//// Copyright (C) 2017 Authors and OPENCORES.ORG                 ////

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//////////////////////////////////////////////////////////////////////

module

  riffa_register_file

  #(

    // A, //  address bus width

    N, //  data bus width in bytes

    MW = 3 //  mux select width

  )

  (

    riffa_chnl_if chnl_in,

    riffa_register_if r_if,

    input clk,  // must be same clock domain as rx_clk & tx_clk

    input reset // must be same clock domain as rx_clk & tx_clk

  );

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

// synthesis translate_off

    initial

      a_data_bus_mod: assert(N % 4 == 0) else $fatal;

// synthesis translate_on

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

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

  //

  localparam RW = (N/4); // width of the bus in 32 bit words

  localparam MI = 2 ** MW; //  mux inputs

  localparam LB = $clog2(RW);

  localparam UB = LB + MW;

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

  //

  wire rx_done;

  wire [31:0] rx_index;

  wire rx_last;

  wire [31:0] rx_len;

  wire [30:0] rx_off;

  wire rx_data_ren;

  wire rd_empty;

  wire [(8*N)-1:0] rd_data;

  wire rd_en;

  riffa_chn_rx #(.N(N))

    riffa_chn_rx_i(.*);

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

  //

  wire register_select [MI-1:0];

  genvar j;

  generate

    for(j = 0; j < MI; j = j + 1)

    begin: decoder_gen

      assign register_select[j] = (rx_index[UB:LB] == j) & (rx_index[31:UB] == 0) ? 1 : 0;

      always_ff @(posedge clk)

        if(reset)

          r_if.register_out[j] <= 0;

        else if(rd_en & register_select[j])

          r_if.register_out[j] <= rd_data;

    end

  endgenerate

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

  //

  assign chnl_in.rx_data_ren = rx_data_ren;

  assign rd_en = ~rd_empty;

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

  //

  wire tx_ready = 1;

  wire tx_last = 1;

  wire [31:0] tx_len = RW*MI;

  wire [30:0] tx_off = 0;

  wire [31:0] tx_index;

  wire tx_done = (tx_index >= chnl_in.tx_len - RW);

  riffa_chn_tx #(.N(N))

    riffa_chn_tx_i(.*);

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

  //

  recursive_mux #(.A(MW), .W(N*8))

    recursive_mux_i

    (

      .select(tx_index[UB:LB]),

      .data_in(r_if.register_in),

      .data_out(chnl_in.tx_data)

    );

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

  //

  assign chnl_in.rx_clk = clk;

  assign chnl_in.tx_clk = clk;

  assign chnl_in.rx_reset = reset;

  assign chnl_in.tx_reset = reset;

  assign chnl_in.tx_last = 1;

  assign chnl_in.tx_len = RW*MI;

  assign chnl_in.tx_off = 0;

  assign chnl_in.tx_data_valid = 1;

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

//

endmodule