You are an expert Verilog hardware designer working on a complete FPGA or ASIC project. You are given the full source code of a Verilog project. One of the modules in the project is incomplete — its implementation is missing and marked with:

// >>> Module Implementation Begin

// <<< Module Implementation End

Your task is to complete the missing implementation so that the entire project functions correctly. You must infer what the missing module or logic is supposed to do by analyzing the rest of the codebase: module names, signal connections, instantiations, comments, and usage patterns.

Follow these rules:

1. Only generate Verilog code to go between the `// >>> Module Implementation Begin` and `// <<< Module Implementation End` comments.
2. Use Verilog-2001 syntax. Ensure the code is synthesizable.
3. Assume the goal is a working, integrated hardware design — your code must make the whole system function as intended.
4. Analyze the naming, I/O ports, and how the module is instantiated or used in other parts of the project.
5. Implement correct behavior based on design context. Do not guess randomly — reason it out.
6. Avoid vendor-specific features unless explicitly required.
7. Do not output comments, explanation, or anything outside the required code region unless explicitly asked.

Your output should contain **only the Verilog code** that fits inside the marked region.

/*
 * Copyright (c) 2024 Your Name
 * SPDX-License-Identifier: Apache-2.0
 */

`default_nettype none

module tt_um_router (
    input  wire [7:0] ui_in,    // Dedicated inputs
    output wire [7:0] uo_out,   // Dedicated outputs
    input  wire [7:0] uio_in,   // IOs: Input path
    output wire [7:0] uio_out,  // IOs: Output path
    output wire [7:0] uio_oe,   // IOs: Enable path (active high: 0=input, 1=output)
    input  wire       ena,      // always 1 when the design is powered, so you can ignore it
    input  wire       clk,      // clock
    input  wire       rst_n     // reset_n - low to reset
);
assign uio_oe=8'b11111111;

assign uio_out[7:6]=2'b00;

router_top router_top (
		.clock(clk),
		.resetn(rst_n),
		.data_in(ui_in[2:0]),
		.pkt_valid(ui_in[3]),
		.read_enb_0(ui_in[4]),
		.read_enb_1(ui_in[5]),
		.read_enb_2(ui_in[6]),
		.data_out_0(uo_out[2:0]),
		.data_out_1(uo_out[5:3]),
		.data_out_2(uio_out[2:0]),
		.vld_out_0(uio_out[3]),
		.vld_out_1(uio_out[4]),
		.vld_out_2(uio_out[5]),
		.err(uo_out[6]),
		.busy(uo_out[7])
		);


endmodule





module router_fifo(clock,resetn,soft_reset,write_enb,read_enb,
                   lfd_state,data_in,full,empty,data_out);
  
  input clock,resetn,soft_reset;
  input write_enb,read_enb,lfd_state;
  input [2:0]data_in;
  
  output reg [2:0] data_out;
  output full,empty;
  
  reg [4:0] rd_pointer,wr_pointer;
  reg [6:0] count;
  reg [8:0] mem [15:0];

  integer i;
  
   reg lfd_state_t;
  
  always@(posedge clock)
    begin
      if(!resetn)
        lfd_state_t <= 0;
      else
        lfd_state_t <= lfd_state;
    end 
   
  // ------Read Operation-------
  always@(posedge clock) 
    begin
      if(!resetn)
          data_out = 3'b0;
      else if(soft_reset) 
          data_out = 3'bz;
      else if((read_enb) && (!empty))
        data_out = mem[rd_pointer[2:0]][2:0];
      else if(count == 0)
           data_out = 3'bz;
    end
  
  // ------Write Operation------ 
  always@(posedge clock) 
    begin
      if(!resetn || soft_reset)
         begin
            for(i=0;i<16;i=i+1)
            mem[i]<=0;
         end
      else if(write_enb&&(~full))   
         begin
           if(lfd_state_t)
	           begin
                 mem[wr_pointer[3:0]][8]<=1'b1;
                 mem[wr_pointer[2:0]][2:0]<=data_in;
	           end
      
	      else
	           begin
                 mem[wr_pointer[3:0]][8]<=1'b0;
                 mem[wr_pointer[2:0]][2:0]<=data_in;
			   end
         end
     end

      
    
  
  //----Pointer generation block----

   always@(posedge clock) 
     begin
       if(!resetn)
        wr_pointer<=0;
      else if(write_enb && (~full))
        wr_pointer<=wr_pointer+1;
     end
   
   always@(posedge clock) //Read address
     begin
       if(!resetn)
         rd_pointer<=0;
       else if(read_enb && (~empty))
         rd_pointer<=rd_pointer+1;
     end
  
  
  //-----counter block while reading------
  
  always@(posedge clock)
    begin
      if(read_enb && !empty)
        begin
          if((mem[rd_pointer[3:0]][8])==1'b1)
            count <= mem[rd_pointer[3:0]][7:2] + 1'b1;
          else if(count != 0)
            count <= count - 1'b1;
        end
    end
  //---------Full & empty condition-----------
  assign full  = (wr_pointer ==({~rd_pointer[4],rd_pointer[3:0]}));
  assign empty = (rd_pointer == wr_pointer);
  
  
endmodule




module router_fsm(clock,resetn,pkt_valid,data_in,fifo_full,fifo_empty_0,fifo_empty_1,fifo_empty_2,
                  soft_reset_0,soft_reset_1,soft_reset_2,parity_done,low_packet_valid,
                  write_enb_reg,detect_add,ld_state,laf_state,lfd_state,full_state,rst_int_reg,busy);

input clock,resetn,pkt_valid,fifo_full,fifo_empty_0,fifo_empty_1,fifo_empty_2;
input soft_reset_0,soft_reset_1,soft_reset_2,parity_done,low_packet_valid;
input [1:0] data_in;
output write_enb_reg,detect_add,ld_state,laf_state,lfd_state,full_state,rst_int_reg,busy;
  
  
parameter DECODE_ADDRESS     = 3'b000,
          LOAD_FIRST_DATA 	 = 3'b001,
          LOAD_DATA 		 = 3'b010,
          WAIT_TILL_EMPTY 	 = 3'b011,
          CHECK_PARITY_ERROR = 3'b100,
          LOAD_PARITY 		 = 3'b101,
          FIFO_FULL_STATE 	 = 3'b110,
          LOAD_AFTER_FULL 	 = 3'b111;
  
  reg [2:0] PS,NS;
          
  always@(posedge clock)
    begin
      if(!resetn)
        PS <= DECODE_ADDRESS;
      else if(soft_reset_0 || soft_reset_1 || soft_reset_2)
        PS <= DECODE_ADDRESS;
      else 
        PS <= NS;
    end
  
  
  always@(*)
    begin
      NS = DECODE_ADDRESS;
      case(PS)
        
        DECODE_ADDRESS : 
                  begin
                    if((pkt_valid && (data_in[1:0]==0) && fifo_empty_0)||
                       (pkt_valid && (data_in[1:0]==1) && fifo_empty_1)||
                       (pkt_valid && (data_in[1:0]==2) && fifo_empty_2))
                      
                      NS = LOAD_FIRST_DATA;
                    
                    else if((pkt_valid && (data_in[1:0]==0) && (~fifo_empty_0))||
                            (pkt_valid && (data_in[1:0]==1) && (~fifo_empty_1))||
                            (pkt_valid && (data_in[1:0]==2) && (~fifo_empty_2)))
                      
                      NS = WAIT_TILL_EMPTY;
                    
                    else
                      NS = DECODE_ADDRESS;
                  end
        
        LOAD_FIRST_DATA :  NS = LOAD_DATA;
        
        LOAD_DATA       : 
                        begin
			      			if(fifo_full)
				 				NS=FIFO_FULL_STATE;
                          else if(!fifo_full && !pkt_valid)
				 				NS=LOAD_PARITY;
			      			else
				 				NS=LOAD_DATA;
			   			end 
        
        WAIT_TILL_EMPTY  : 
                        begin
                          if((!fifo_empty_0) || (!fifo_empty_1) || (!fifo_empty_2))
				 			NS=WAIT_TILL_EMPTY;
			      		  else if(fifo_empty_0||fifo_empty_1||fifo_empty_2)
				 			NS=LOAD_FIRST_DATA;
			      		  else
				 			NS=WAIT_TILL_EMPTY;
                         end
        
        CHECK_PARITY_ERROR:
          				begin
			    			if(fifo_full)
			      	 			NS=FIFO_FULL_STATE;
			    			else
			         			NS=DECODE_ADDRESS;

			   			 end

       LOAD_PARITY     	  :	NS=CHECK_PARITY_ERROR;
			 

       FIFO_FULL_STATE	  :	   
          				begin
                        	if(!fifo_full)
			         			NS=LOAD_AFTER_FULL;
			      			else if(fifo_full)
			         			NS=FIFO_FULL_STATE;
			  		 		end
        
        LOAD_AFTER_FULL:	   
          				begin
          					if((!parity_done) && (!low_packet_valid))
			   					NS=LOAD_DATA;
          					else if((!parity_done) && (low_packet_valid))
			   					NS=LOAD_PARITY;
          					else if(parity_done)
			   					NS=DECODE_ADDRESS;
			   			 end
        
      endcase
   end
  
  assign detect_add = ((PS==DECODE_ADDRESS)?1:0); 
  assign write_enb_reg=((PS==LOAD_DATA||PS==LOAD_PARITY||PS==LOAD_AFTER_FULL)?1:0);
  assign full_state=((PS==FIFO_FULL_STATE)?1:0);
  assign lfd_state=((PS==LOAD_FIRST_DATA)?1:0);
  assign busy=((PS==FIFO_FULL_STATE||PS==LOAD_AFTER_FULL||PS==WAIT_TILL_EMPTY||PS==LOAD_FIRST_DATA||PS==LOAD_PARITY||PS==CHECK_PARITY_ERROR)?1:0);
  //assign busy=((PS==LOAD_DATA || PS==DECODE_ADDRESS)?0:1);
  assign ld_state=((PS==LOAD_DATA)?1:0);
  assign laf_state=((PS==LOAD_AFTER_FULL)?1:0);
  assign rst_int_reg=((PS==CHECK_PARITY_ERROR)?1:0);
  
endmodule
  




module router_reg(clock,resetn,pkt_valid,data_in,fifo_full,detect_add,
                  ld_state,laf_state,full_state,lfd_state,rst_int_reg,err,
                  parity_done,low_packet_valid,dout);
// >>> Module Implementation Begin

// <<< Module Implementation End
endmodule





module router_sync(clock,resetn,data_in,detect_add,full_0,full_1,full_2,empty_0,empty_1,empty_2,write_enb_reg,read_enb_0,read_enb_1,read_enb_2,write_enb,fifo_full,vld_out_0,vld_out_1,vld_out_2,soft_reset_0,soft_reset_1,soft_reset_2);


input clock,resetn,detect_add,full_0,full_1,full_2,empty_0,empty_1,empty_2,write_enb_reg,read_enb_0,read_enb_1,read_enb_2;
input [1:0]data_in;
output reg[2:0]write_enb;
output reg fifo_full,soft_reset_0,soft_reset_1,soft_reset_2;
output vld_out_0,vld_out_1,vld_out_2;

  reg [1:0] data_in_tmp;
  reg[4:0]count0,count1,count2;
  
  always@(posedge clock)
  begin
    if(~resetn)
    data_in_tmp<=0;
    else if(detect_add)
    data_in_tmp<=data_in;
  end
  
  
  
//-----------Address decoding & fifo empty ---------------
always@(*)
  begin
    case(data_in_tmp)
    2'b00:begin
	  fifo_full<=full_0;
	  if(write_enb_reg)
	  write_enb<=3'b001;
	  else
	  write_enb<=0;
	  end
    2'b01:begin
	  fifo_full<=full_1;
	  if(write_enb_reg)
	  write_enb<=3'b010;
	  else
	  write_enb<=0;
	  end
    2'b10:begin
	  fifo_full<=full_2;
	  if(write_enb_reg)
	  write_enb<=3'b100;
	  else
	  write_enb<=0;
	  end
    default:begin
	  fifo_full<=0;
	  write_enb<=0;
	  end
    endcase
  end
  
  
  
//-----------------------------------Valid Byte block----------------------------------

assign vld_out_0 = (~empty_0);
assign vld_out_1 = (~empty_1);
assign vld_out_2 = (~empty_2);

  
//-----------------------------------Soft Reset block----------------------------------

always@(posedge clock)
  begin
  
  if(~resetn)
  begin
  count0<=0;
  soft_reset_0<=0;
  end

  else if(vld_out_0)
  begin
  if(~read_enb_0)
   
    begin
    if(count0==29)
      begin
      soft_reset_0<=1'b1;
      count0<=0;
      end
    else
      begin
      soft_reset_0<=1'b0;
      count0<=count0+1'b1;
      end
    end
  else
  count0<=0;
  end
  end

always@(posedge clock)
  begin
  
  if(~resetn)
  begin
  count1<=0;
  soft_reset_1<=0;
  end

  else if(vld_out_1)
  begin
  if(~read_enb_1)
   
    begin
    if(count1==29)
      begin
      soft_reset_1<=1'b1;
      count1<=0;
      end
    else
      begin
      soft_reset_1<=1'b0;
      count1<=count1+1'b1;
      end
    end
  else
  count1<=0;
  end
  end

always@(posedge clock)
  begin
  
  if(~resetn)
  begin
  count2<=0;
  soft_reset_2<=0;
  end

  else if(vld_out_2)
  begin
  if(~read_enb_2)
   
    begin
    if(count2==29)
      begin
      soft_reset_2<=1'b1;
      count2<=0;
      end
    else
      begin
      soft_reset_2<=1'b0;
      count2<=count2+1'b1;
      end
    end
  else
  count2<=0;
  end
  end

endmodule
  




module router_top(clock,resetn,pkt_valid,read_enb_0,read_enb_1,read_enb_2,data_in,
				    busy,err,vld_out_0,vld_out_1,vld_out_2,data_out_0,data_out_1,data_out_2);
  
  input [2:0]data_in;
  input pkt_valid,clock,resetn,read_enb_0,read_enb_1,read_enb_2;
  output [2:0]data_out_0,data_out_1,data_out_2;
  output vld_out_0,vld_out_1,vld_out_2,err,busy;
	
	wire soft_reset_0,full_0,empty_0,soft_reset_1,full_1,empty_1,soft_reset_2,full_2,empty_2,
         fifo_full,detect_add,ld_state,laf_state,full_state,lfd_state,rst_int_reg,
         parity_done,low_packet_valid,write_enb_reg;
	wire [2:0]write_enb;
	wire [2:0]d_in;
	
    //-------fifo instantiation-----
    
   
	
	router_fifo FIFO_0(.clock(clock),
	                   .resetn(resetn),
		           .soft_reset(soft_reset_0),
			   .write_enb(write_enb[0]),
			   .read_enb(read_enb_0),
                           .lfd_state(lfd_state),
			   .data_in(d_in),
			   .full(full_0),
			   .empty(empty_0),
			   .data_out(data_out_0));
				   
				   
				   
				   
				   
	
	router_fifo FIFO_1(.clock(clock),
	                   .resetn(resetn),
			   .soft_reset(soft_reset_1),
			   .write_enb(write_enb[1]),
			   .read_enb(read_enb_1),
                           .lfd_state(lfd_state),
		           .data_in(d_in),
			   .full(full_1),
			   .empty(empty_1),
			   .data_out(data_out_1));
					   
					   
	
	router_fifo FIFO_2(.clock(clock),
	                   .resetn(resetn),
			   .soft_reset(soft_reset_2),
			   .write_enb(write_enb[2]),
			   .read_enb(read_enb_2),
                           .lfd_state(lfd_state),
			   .data_in(d_in),
			   .full(full_2),
			   .empty(empty_2),
			   .data_out(data_out_2));
    
    //-------register instantiation-----	
    
	router_reg REGISTER(.clock(clock),
	                    .resetn(resetn),
			    .pkt_valid(pkt_valid),
	        	    .data_in(data_in),
			    .fifo_full(fifo_full),
	        	    .detect_add(detect_add),
                            .ld_state(ld_state),
			    .laf_state(laf_state),
			    .full_state(full_state),
	       		    .lfd_state(lfd_state),
			    .rst_int_reg(rst_int_reg),
			    .err(err),
                            .parity_done(parity_done),
			    .low_packet_valid(low_packet_valid),
			    .dout(d_in));
				  
				  
				  
				  
    				
    //-------synchronizer instantiation-----

      
    
							 
	router_sync SYNCHRONIZER(.clock(clock),
	                         .resetn(resetn),
				 .data_in(data_in[1:0]),
				 .detect_add(detect_add),
				 .full_0(full_0),
				 .full_1(full_1),
				 .full_2(full_2),
				 .empty_0(empty_0),
				 .empty_1(empty_1),
				 .empty_2(empty_2),
				 .write_enb_reg(write_enb_reg),
				 .read_enb_0(read_enb_0),
				 .read_enb_1(read_enb_1),
				 .read_enb_2(read_enb_2),
				 .write_enb(write_enb),
				 .fifo_full(fifo_full),
				 .vld_out_0(vld_out_0),
				 .vld_out_1(vld_out_1),
				 .vld_out_2(vld_out_2),
				 .soft_reset_0(soft_reset_0),
				 .soft_reset_1(soft_reset_1),
				 .soft_reset_2(soft_reset_2));						 
							 
							 
							 
    //-------fsm instantiation-----
    
	router_fsm FSM(.clock(clock),
	               .resetn(resetn),
		       .pkt_valid(pkt_valid),
		       .data_in(data_in[1:0]),
		       .fifo_full(fifo_full),
		       .fifo_empty_0(empty_0),
		       .fifo_empty_1(empty_1),
		       .fifo_empty_2(empty_2),
                       .soft_reset_0(soft_reset_0),
		       .soft_reset_1(soft_reset_1),
		       .soft_reset_2(soft_reset_2),
		       .parity_done(parity_done),
		       .low_packet_valid(low_packet_valid),
                       .write_enb_reg(write_enb_reg),
	               .detect_add(detect_add),
		       .ld_state(ld_state),
		       .laf_state(laf_state),
		       .lfd_state(lfd_state),
		       .full_state(full_state),
	               .rst_int_reg(rst_int_reg),
	               .busy(busy));
   
endmodule


Reference solution:
rtl/generated.v: 
input clock,resetn,pkt_valid,fifo_full,detect_add,ld_state,laf_state,full_state,lfd_state,rst_int_reg;
input [2:0]data_in;
output reg err,parity_done,low_packet_valid;
output reg [2:0]dout;
reg [2:0]header,int_reg,int_parity,ext_parity;
  
  
  //------------------------------DATA OUT LOGIC---------------------------------

	always@(posedge clock)
   	begin
      if(!resetn)
      	begin
	     dout    	 <=0;
	     header  	 <=0;
	     int_reg 	 <=0;
       	end
      else if(detect_add && pkt_valid && data_in[1:0]!=2'b11)
	     header<=data_in;
      else if(lfd_state)
	     dout<=header;
      else if(ld_state && !fifo_full)
	     dout<=data_in;
      else if(ld_state && fifo_full)
	     int_reg<=data_in;
      else if(laf_state)
	     dout<=int_reg;
     end

  //---------------------------LOW PACKET VALID LOGIC----------------------------
	
      	always@(posedge clock)
	   		begin
              if(!resetn)
	 				low_packet_valid<=0; 
         		else if(rst_int_reg)
	 				low_packet_valid<=0;

              else if(ld_state && !pkt_valid) 
         			low_packet_valid<=1;
			end
  //----------------------------PARITY DONE LOGIC--------------------------------
	
	always@(posedge clock)
	begin
      if(!resetn)
	  parity_done<=0;
     else if(detect_add)
	  parity_done<=0;
      else if((ld_state && !fifo_full && !pkt_valid)
              ||(laf_state && low_packet_valid && !parity_done))
	  parity_done<=1;
	end

//---------------------------PARITY CALCULATE LOGIC----------------------------

	always@(posedge clock)
	begin
      if(!resetn)
	 int_parity<=0;
	else if(detect_add)
	 int_parity<=0;
	else if(lfd_state && pkt_valid)
	 int_parity<=int_parity^header;
	else if(ld_state && pkt_valid && !full_state)
	 int_parity<=int_parity^data_in;
	else
	 int_parity<=int_parity;
	end
	 

//-------------------------------ERROR LOGIC-----------------------------------

	always@(posedge clock)
		begin
          if(!resetn)
	  			err<=0;
	      else if(parity_done)
	       		begin
	 				if (int_parity==ext_parity)
	    				err<=0;
	 				else 
	    			err<=1;
	 			end
	 	   else
	    		err<=0;
	      end

//-------------------------------EXTERNAL PARITY LOGIC-------------------------

	always@(posedge clock)
	begin
      if(!resetn)
	  		ext_parity<=0;
      else if(detect_add)
	  		ext_parity<=0;
      else if((ld_state && !fifo_full && !pkt_valid) || (laf_state && !parity_done && low_packet_valid))
	  		ext_parity<=data_in;
	 end