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/* *****************************************************************

 *

 *  This file is part of the

 *

 *  Tone Order and Constellation Encoder Core.

 *

 *  Description:

 *

 *  The conste_enc module implements the tone ordering and

 *  constellation encoding as described in ITU G.992.1

 *

 *********************************************************************

 *  Copyright (C) 2007 Guenter Dannoritzer

 *

 *   This source 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 source 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 source.

 *   If not, see <http://www.gnu.org/licenses/>.

 *

 * *****************************************************************/

module const_encoder(

                clk,

                reset,

                fast_ready_o,

                we_fast_data_i,

                fast_data_i,

                inter_ready_o,

                we_inter_data_i,

                inter_data_i,

                addr_i,

                we_conf_i,

                conf_data_i,

                xy_ready_o,

                carrier_num_o,

                x_o,

                y_o);

`include "parameters.vh"

//

// parameter

// 

input                 clk;

input                 reset;

output                fast_ready_o;

input                 we_fast_data_i;

input   [DW-1:0]      fast_data_i;

output                inter_ready_o;

input                 we_inter_data_i;

input   [DW-1:0]      inter_data_i;

input   [CONFAW-1:0]  addr_i;

input                 we_conf_i;

input   [CONFDW-1:0]  conf_data_i;

output                xy_ready_o;

output  [CNUMW-1:0]   carrier_num_o;

output  [CONSTW-1:0]  x_o;            reg [CONSTW-1:0] x_o;

output  [CONSTW-1:0]  y_o;            reg [CONSTW-1:0] y_o;

//

// local wire/regs

//

wire    [DW-1:0]          fast_data_o;

wire    [DW-1:0]          inter_data_o;

reg   [SHIFTW-1:0]        fast_shift_reg;

reg   [SHIFTW-1:0]        inter_shift_reg;

reg   [MAXBITNUM-1:0]     cin;

reg   [CONFDW-1:0]        bit_load;

reg   [4:0]               msb;

reg   [1:0]               msb_x;

reg   [1:0]               msb_y;

reg   [CONFDW-1:0]        BitLoading [0:REG_MEM_LEN-1];

reg   [CONFDW-1:0]        CarrierNumber [0:REG_MEM_LEN-1];

reg   [USED_C_REG_W-1:0]  UsedCarrier;

reg   [F_BITS_W-1:0]      FastBits;

//

// intantiate the fast path and interleaved path FIFOs

//

fifo  #(.AWIDTH(AW), .DWIDTH(DW))

      fifo_fast ( .clk(clk),

                  .reset(reset),

                  .empty_o(fast_empty_o),

                  .full_o(fast_full_o),

                  .one_available_o(fast_one_available_o),

                  .two_available_o(fast_two_available_o),

                  .we_i(we_fast_i),

                  .data_i(fast_data_i),

                  .re_i(re_fast_i),

                  .data_o(fast_data_o)

                  );

fifo  #(.AWIDTH(AW), .DWIDTH(DW))

      fifo_inter ( .clk(clk),

                  .reset(reset),

                  .empty_o(inter_empty_o),

                  .full_o(inter_full_o),

                  .one_available_o(inter_one_available_o),

                  .two_available_o(inter_two_available_o),

                  .we_i(we_inter_i),

                  .data_i(inter_data_i),

                  .re_i(re_inter_i),

                  .data_o(inter_data_o)

                  );

//

// configuration register access

//

always @(posedge clk or posedge reset) begin

  if(reset) begin

    UsedCarrier <= 0;

    FastBits <= 0;

  end

  else begin

    if(we_conf_i) begin

      if(addr_i >= 0 && addr_i < C_NUM_ST_ADR) begin

        BitLoading[addr_i] <= conf_data_i;

      end

      else if(addr_i >= C_NUM_ST_ADR && addr_i < USED_C_ADR) begin

        CarrierNumber[addr_i - C_NUM_ST_ADR] <= conf_data_i;

      end

      else if(addr_i == USED_C_ADR) begin

        UsedCarrier <= conf_data_i;

      end

      else if(addr_i == F_BITS_ADR) begin

        FastBits <= conf_data_i;

      end

    end

  end

end

//

// constellation mapping

//

always @(posedge reset or posedge clk) begin

  if(reset) begin

    x_o <= 9'b0;

    y_o <= 9'b0;

  end

  else begin

    case (bit_load)

      4'b0010:  begin // #2

                  x_o <= {cin[0], cin[0], cin[0], cin[0], cin[0], cin[0], cin[0], cin[0], 1'b1};

                  y_o <= {cin[1], cin[1], cin[1], cin[1], cin[1], cin[1], cin[1], cin[1], 1'b1};

                end

      4'b0011:  begin // #3

                  case (cin[2:0])

                    3'b000: begin x_o <= 9'b000000001; y_o <= 9'b000000011; end

                    3'b001: begin x_o <= 9'b000000001; y_o <= 9'b111111111; end

                    3'b010: begin x_o <= 9'b111111111; y_o <= 9'b000000001; end

                    3'b011: begin x_o <= 9'b111111111; y_o <= 9'b111111111; end

                    3'b100: begin x_o <= 9'b111111101; y_o <= 9'b000000001; end

                    3'b101: begin x_o <= 9'b000000001; y_o <= 9'b000000011; end

                    3'b110: begin x_o <= 9'b111111111; y_o <= 9'b111111101; end

                    3'b111: begin x_o <= 9'b000000011; y_o <= 9'b111111111; end

                  endcase

                end

      4'b0100:  begin // #4

                  x_o <= {cin[2], cin[2], cin[2], cin[2], cin[2], cin[2], cin[2], cin[0], 1'b1};

                  y_o <= {cin[3], cin[3], cin[3], cin[3], cin[3], cin[3], cin[3], cin[1], 1'b1};

                end

      4'b0101:  begin // #5

                  map_msb(cin[4:0], msb_x, msb_y);

                  x_o <= {msb_x[1], msb_x[1], msb_x[1], msb_x[1], msb_x[1], msb_x[1], msb_x[0], 1'b1};

                  y_o <= {msb_y[1], msb_y[1], msb_y[1], msb_y[1], msb_y[1], msb_y[1], msb_y[0], 1'b1};

                end

      4'b0110:  begin // #6

                  x_o <= {cin[4], cin[4], cin[4], cin[4], cin[4], cin[4], cin[2], cin[0], 1'b1};

                  y_o <= {cin[5], cin[5], cin[5], cin[5], cin[5], cin[5], cin[3], cin[1], 1'b1};

                end

      4'b0111:  begin // #7

                  map_msb(cin[6:2], msb_x, msb_y);

                  x_o <= {msb_x[1], msb_x[1], msb_x[1], msb_x[1], msb_x[1], msb_x[0], cin[2], cin[0], 1'b1};

                  y_o <= {msb_y[1], msb_y[1], msb_y[1], msb_y[1], msb_y[1], msb_y[0], cin[3], cin[1], 1'b1};

                end

      4'b1000:  begin // #8

                  x_o <= {cin[6], cin[6], cin[6], cin[6], cin[6], cin[4], cin[2], cin[0], 1'b1};

                  y_o <= {cin[7], cin[7], cin[7], cin[7], cin[7], cin[5], cin[3], cin[1], 1'b1};

                end

      4'b1001:  begin // #9

                  map_msb(cin[7:3], msb_x, msb_y);

                  x_o <= {msb_x[1], msb_x[1], msb_x[1], msb_x[1], msb_x[0], cin[4], cin[2], cin[0], 1'b1};

                  y_o <= {msb_y[1], msb_y[1], msb_y[1], msb_y[1], msb_y[0], cin[5], cin[3], cin[1], 1'b1};

                end

      4'b1010:  begin // #10

                  x_o <= {cin[8], cin[8], cin[8], cin[8], cin[6], cin[4], cin[2], cin[0], 1'b1};

                  y_o <= {cin[9], cin[9], cin[9], cin[9], cin[7], cin[5], cin[3], cin[1], 1'b1};

                end

      4'b1011:  begin // #11

                  map_msb(cin[8:4], msb_x, msb_y);

                  x_o <= {msb_x[1], msb_x[1], msb_x[1], msb_x[0], cin[6], cin[4], cin[2], cin[0], 1'b1};

                  y_o <= {msb_y[1], msb_y[1], msb_y[1], msb_y[0], cin[7], cin[5], cin[3], cin[1], 1'b1};

                end

      4'b1100:  begin // #12

                  x_o <= {cin[10], cin[10], cin[10], cin[8], cin[6], cin[4], cin[2], cin[0], 1'b1};

                  y_o <= {cin[11], cin[11], cin[11], cin[9], cin[7], cin[5], cin[3], cin[1], 1'b1};

                end

      4'b1101:  begin // #13

                  map_msb(cin[9:5], msb_x, msb_y);

                  x_o <= {msb_x[1], msb_x[1], msb_x[0], cin[8], cin[6], cin[4], cin[2], cin[0], 1'b1};

                  y_o <= {msb_y[1], msb_y[1], msb_y[0], cin[9], cin[7], cin[5], cin[3], cin[1], 1'b1};

                end

      4'b1110:  begin // #14

                  x_o <= {cin[12], cin[12], cin[10], cin[8], cin[6], cin[4], cin[2], cin[0], 1'b1};

                  y_o <= {cin[13], cin[13], cin[11], cin[9], cin[7], cin[5], cin[3], cin[1], 1'b1};

                end

      4'b1111:  begin // #15 TODO

                  map_msb(cin[10:6], msb_x, msb_y);

                  x_o <= {msb_x[1], msb_x[0], cin[10], cin[8], cin[6], cin[4], cin[2], cin[0], 1'b1};

                  y_o <= {msb_y[1], msb_y[0], cin[11], cin[9], cin[7], cin[5], cin[3], cin[1], 1'b1};

                end

    endcase

  end

end

//

// determine the top two bits of X and Y based on table 7-12 in G.992.1

//

task map_msb(input [4:0] t_msb, output [1:0] t_msb_x, output [1:0] t_msb_y );

  begin

  case (t_msb)

    5'b00000: begin t_msb_x <= 2'b00; t_msb_y <= 2'b00; end

    5'b00001: begin t_msb_x <= 2'b00; t_msb_y <= 2'b00; end

    5'b00010: begin t_msb_x <= 2'b00; t_msb_y <= 2'b00; end

    5'b00011: begin t_msb_x <= 2'b00; t_msb_y <= 2'b00; end

    5'b00100: begin t_msb_x <= 2'b00; t_msb_y <= 2'b11; end

    5'b00101: begin t_msb_x <= 2'b00; t_msb_y <= 2'b11; end

    5'b00110: begin t_msb_x <= 2'b00; t_msb_y <= 2'b11; end

    5'b00111: begin t_msb_x <= 2'b00; t_msb_y <= 2'b11; end

    5'b01000: begin t_msb_x <= 2'b11; t_msb_y <= 2'b00; end

    5'b01001: begin t_msb_x <= 2'b11; t_msb_y <= 2'b00; end

    5'b01010: begin t_msb_x <= 2'b11; t_msb_y <= 2'b00; end

    5'b01011: begin t_msb_x <= 2'b11; t_msb_y <= 2'b00; end

    5'b01100: begin t_msb_x <= 2'b11; t_msb_y <= 2'b11; end

    5'b01101: begin t_msb_x <= 2'b11; t_msb_y <= 2'b11; end

    5'b01110: begin t_msb_x <= 2'b11; t_msb_y <= 2'b11; end

    5'b01111: begin t_msb_x <= 2'b11; t_msb_y <= 2'b11; end

    5'b10000: begin t_msb_x <= 2'b01; t_msb_y <= 2'b00; end

    5'b10001: begin t_msb_x <= 2'b01; t_msb_y <= 2'b00; end

    5'b10010: begin t_msb_x <= 2'b10; t_msb_y <= 2'b00; end

    5'b10011: begin t_msb_x <= 2'b10; t_msb_y <= 2'b00; end

    5'b10100: begin t_msb_x <= 2'b00; t_msb_y <= 2'b01; end

    5'b10101: begin t_msb_x <= 2'b00; t_msb_y <= 2'b10; end

    5'b10110: begin t_msb_x <= 2'b00; t_msb_y <= 2'b01; end

    5'b10111: begin t_msb_x <= 2'b00; t_msb_y <= 2'b10; end

    5'b11000: begin t_msb_x <= 2'b11; t_msb_y <= 2'b01; end

    5'b11001: begin t_msb_x <= 2'b11; t_msb_y <= 2'b10; end

    5'b11010: begin t_msb_x <= 2'b11; t_msb_y <= 2'b01; end

    5'b11011: begin t_msb_x <= 2'b11; t_msb_y <= 2'b10; end

    5'b11100: begin t_msb_x <= 2'b01; t_msb_y <= 2'b11; end

    5'b11101: begin t_msb_x <= 2'b01; t_msb_y <= 2'b11; end

    5'b11110: begin t_msb_x <= 2'b10; t_msb_y <= 2'b11; end

    5'b11111: begin t_msb_x <= 2'b10; t_msb_y <= 2'b11; end

  endcase

end

endtask

endmodule