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

////                                                              ////

////  File name "tx_enqueue.v"                                    ////

////                                                              ////

////  This file is part of the "10GE MAC" project                 ////

////  http://www.opencores.org/cores/xge_mac/                     ////

////                                                              ////

////  Author(s):                                                  ////

////      - A. Tanguay (antanguay@opencores.org)                  ////

////                                                              ////

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

////                                                              ////

//// Copyright (C) 2008 AUTHORS. All rights reserved.             ////

////                                                              ////

//// This source file may be used and distributed without         ////

//// restriction provided that this copyright statement is not    ////

//// removed from the file and that any derivative work contains  ////

//// the original copyright notice and the associated disclaimer. ////

////                                                              ////

//// This source file is free software; you can redistribute it   ////

//// and/or modify it under the terms of the GNU Lesser General   ////

//// Public License as published by the Free Software Foundation; ////

//// either version 2.1 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 Lesser General Public License for more ////

//// details.                                                     ////

////                                                              ////

//// You should have received a copy of the GNU Lesser General    ////

//// Public License along with this source; if not, download it   ////

//// from http://www.opencores.org/lgpl.shtml                     ////

////                                                              ////

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

`include "defines.v"

module tx_enqueue(/*AUTOARG*/

  // Outputs

  pkt_tx_full, txdfifo_wdata, txdfifo_wstatus, txdfifo_wen,

  status_txdfifo_ovflow_tog,

  // Inputs

  clk_156m25, reset_156m25_n, pkt_tx_data, pkt_tx_val, pkt_tx_sop,

  pkt_tx_eop, pkt_tx_mod, txdfifo_wfull, txdfifo_walmost_full

  );

`include "CRC32_D64.v"

`include "CRC32_D8.v"

`include "utils.v"

input         clk_156m25;

input         reset_156m25_n;

input  [63:0] pkt_tx_data;

input         pkt_tx_val;

input         pkt_tx_sop;

input         pkt_tx_eop;

input  [2:0]  pkt_tx_mod;

input         txdfifo_wfull;

input         txdfifo_walmost_full;

output        pkt_tx_full;

output [63:0] txdfifo_wdata;

output [7:0]  txdfifo_wstatus;

output        txdfifo_wen;

output        status_txdfifo_ovflow_tog;

/*AUTOREG*/

// Beginning of automatic regs (for this module's undeclared outputs)

reg                     status_txdfifo_ovflow_tog;

reg [63:0]              txdfifo_wdata;

reg                     txdfifo_wen;

reg [7:0]               txdfifo_wstatus;

// End of automatics

/*AUTOWIRE*/

// Beginning of automatic wires (for undeclared instantiated-module outputs)

// End of automatics

reg             txd_ovflow;

reg             next_txd_ovflow;

// Full status if data fifo is almost full.

// Current packet can complete transfer since data input rate

// matches output rate. But next packet must wait for more headroom.

assign pkt_tx_full = txdfifo_walmost_full;

always @(posedge clk_156m25 or negedge reset_156m25_n) begin

    if (reset_156m25_n == 1'b0) begin

        txd_ovflow <= 1'b0;

        status_txdfifo_ovflow_tog <= 1'b0;

    end

    else begin

        txd_ovflow <= next_txd_ovflow;

        //---

        // FIFO errors, used to generate interrupts

        if (next_txd_ovflow && !txd_ovflow) begin

            status_txdfifo_ovflow_tog <= ~status_txdfifo_ovflow_tog;

        end

    end

end

always @(/*AS*/pkt_tx_data or pkt_tx_eop or pkt_tx_mod or pkt_tx_sop

         or pkt_tx_val or txd_ovflow or txdfifo_wfull) begin

    txdfifo_wstatus = `TXSTATUS_NONE;

    txdfifo_wdata = pkt_tx_data;

    txdfifo_wen = pkt_tx_val;

    next_txd_ovflow = txd_ovflow;

    // Write SOP marker to fifo.

    if (pkt_tx_val && pkt_tx_sop) begin

        txdfifo_wstatus[`TXSTATUS_SOP] = 1'b1;

    end

    // Write EOP marker to fifo.

    if (pkt_tx_val) begin

        if (pkt_tx_eop) begin

            txdfifo_wstatus[2:0] = pkt_tx_mod;

            txdfifo_wstatus[`TXSTATUS_EOP] = 1'b1;

        end

    end

    // Overflow indication

    if (pkt_tx_val) begin

        if (txdfifo_wfull) begin

            next_txd_ovflow = 1'b1;

        end

        else if (pkt_tx_sop) begin

            next_txd_ovflow = 1'b0;

        end

    end

end

endmodule