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_MAC_Accelerator_OnSachinSharma 
(
    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
);

// All output pins must be assigned. If not used, assign to 0.
    
   // assign uio_out=0;
      assign uio_oe=8'b11111111;
    
    
    mac_vedicmul_adder DUT ( .a(ui_in[3:0]), .b(ui_in[7:4]), .C(uo_out), .X(uio_out[3:0]), .Y(uio_out[7:4]), .rst(~rst_n), .clk(clk));
    
// List all unused inputs to prevent warnings
    wire _unused = &{ena,uio_in };
endmodule
// here top module ends

module mac_vedicmul_adder(input clk,rst, input [3:0] a,b,output [7:0] C,output [3:0] X,Y);
wire [7:0] S;
wire [7:0] vedic_out;           
wire co,ci;
assign ci= 0;
pipo_1 u1 (.din(a), .clk(clk),.rst(rst),.pipo_out_1(X));
pipo_1 u2 (.din(b), .clk(clk),.rst(rst),.pipo_out_1(Y));
vedic_4x4 u3(.a(a),.b(b),.result(vedic_out));
assign {co,S} = vedic_out + C + ci;
//Brent_kung_8_bit u4 (.A(vedic_out), .B(C), .Ci(ci), .S(S),.Co(co));
pipo U4(.din(S), .clk(clk),.rst(rst),.pipo_out(C));
endmodule
  ////////////////vedic_mul////////////
  module vedic_4x4(
a, b, result);
    input  [3:0] a,b;
    output [7:0] result;
    wire [7:0] result;

//wire [3:0] w;
wire [3:0] temp1;
wire [5:0] temp2;
wire [5:0] temp3;
wire [5:0] temp4;
wire [3:0] q0;
wire [3:0] q1;
wire [3:0] q2;
wire [3:0] q3;
wire [3:0] q4;
wire [5:0] q5;
wire [5:0] q6;

vedic_2x2 V1(a[1:0], b[1:0], q0[3:0]);
vedic_2x2 V2(a[3:2], b[1:0], q1[3:0]);
vedic_2x2 V3(a[1:0], b[3:2], q2[3:0]);
vedic_2x2 V4(a[3:2], b[3:2], q3[3:0]);

assign temp1= {2'b00, q0[3:2]};
adder4 A0(q1[3:0], temp1, q4);

assign temp2= {2'b00, q2[3:0]};
assign temp3= {q3[3:0], 2'b00};
adder6 A1(temp2, temp3, q5);
assign temp4= {2'b00, q4[3:0]};

adder6 A2(temp4, q5, q6);


assign result[1:0] = q0[1:0];
assign result[7:2] = q6[5:0];
   
endmodule

module vedic_2x2 (a, b, result);
    input [1:0] a,b;
    output [3:0] result;

    wire [3:0] w;
   
   
    assign result[0]= a[0]&b[0];
    assign w[0]     = a[1]&b[0];
    assign w[1]     = a[0]&b[1];
    assign w[2]     = a[1]&b[1];

    halfAdder H0(w[0], w[1], result[1], w[3]);
    halfAdder H1(w[2], w[3], result[2], result[3]);    
   
endmodule

module halfAdder(a,b,sum,carry);
    input a,b;
    output sum, carry;

assign sum   = a ^ b;
assign carry = a & b;

endmodule

module adder4(a,b,sum);
// >>> Module Implementation Begin

// <<< Module Implementation End
endmodule



module adder6(a,b,sum);

input [5:0] a,b;
output [5:0] sum;
wire [5:0] sum;

assign sum = a + b;
endmodule

///////registers//////////////////////////////////////////
module  pipo(din,clk,rst,pipo_out);
input [7:0] din;
input clk,rst;
output [7:0] pipo_out;
wire [7:0] din;
wire clk,rst;
reg [7:0] pipo_out;
always @(posedge clk or posedge rst)
begin
if(rst)
begin
pipo_out <= 8'b0;
end
else
begin
pipo_out <= din;
end
end  
endmodule


module  pipo_1(din,clk,rst,pipo_out_1);
input [3:0] din;
input clk,rst;
output [3:0] pipo_out_1;
wire [3:0] din;
wire clk,rst;
reg [3:0] pipo_out_1;
always @(posedge clk or posedge rst)
begin
if(rst)
begin
pipo_out_1 <= 4'b0;
end
else
begin
pipo_out_1 <= din;
end
end  
endmodule


Reference solution:
rtl/generated.v: 
input [3:0] a,b;
output [3:0] sum;
wire [3:0] sum;

assign sum = a + b;