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_8bitalu (
    input  wire [7:0] ui_in,
    output wire [7:0] uo_out,
    input  wire [7:0] uio_in,
    output wire [7:0] uio_out,
    output wire [7:0] uio_oe,
    input  wire       ena,
    input  wire       clk,
    input  wire       rst_n
);

  // ALU inputs - properly mapped from input pins
  wire [31:0] alu_in_a, alu_in_b;
  wire [4:0]  alu_op;
  wire [31:0] alu_result;
  wire        alu_zero, alu_neg, alu_carry, alu_overflow;

  // Pipeline stage registers
  reg [31:0] pipe1_result, pipe2_result, pipe3_result;
  reg [3:0]  pipe3_flags;

  // Map inputs - extend 8-bit inputs to 32-bit
  assign alu_in_a = {24'b0, ui_in};           // ui_in as operand A
  assign alu_in_b = {24'b0, uio_in[7:3]};     // upper 5 bits of uio_in as operand B  
  assign alu_op = uio_in[4:0];                // lower 5 bits of uio_in as opcode

  // 3-stage pipeline to match typical ALU pipeline depth
  always @(posedge clk or negedge rst_n) begin
    if (!rst_n) begin
      pipe1_result <= 32'b0;
      pipe2_result <= 32'b0;
      pipe3_result <= 32'b0;
      pipe3_flags <= 4'b0;
    end else if (ena) begin
      pipe1_result <= alu_result;
      pipe2_result <= pipe1_result;
      pipe3_result <= pipe2_result;
      pipe3_flags <= {alu_zero, alu_neg, alu_carry, alu_overflow};
    end
  end

  // ALU instantiation
  alu32_pipelined u_alu (
    .a(alu_in_a), 
    .b(alu_in_b), 
    .op(alu_op),
    .result(alu_result),
    .zero(alu_zero), 
    .neg(alu_neg),
    .carry(alu_carry), 
    .overflow(alu_overflow),
    .clk(clk), 
    .rst_n(rst_n)
  );

  // Output assignments
  assign uo_out = pipe3_result[7:0];          // Lower 8 bits of pipelined result
  assign uio_out = {4'b0, pipe3_flags};       // Flags on lower 4 bits
  assign uio_oe = 8'h0F;                      // Enable lower 4 bits for output

endmodule

// Updated ALU Module
module alu32_pipelined (
  input  wire [31:0] a, b,
  input  wire [4:0]  op,
  output reg  [31:0] result,
  output reg         zero, neg, carry, overflow,
  input  wire        clk, rst_n
);
// >>> Module Implementation Begin

// <<< Module Implementation End
endmodule




Reference solution:
rtl/generated.v:   
  reg [32:0] temp_result;
  
  always @(posedge clk or negedge rst_n) begin
    if (!rst_n) begin
      result <= 32'b0;
      zero <= 1'b0;
      neg <= 1'b0;
      carry <= 1'b0;
      overflow <= 1'b0;
    end else begin
      case (op[2:0])  // Use only lower 3 bits for simplicity
        3'b000: temp_result = a + b;        // ADD
        3'b001: temp_result = a - b;        // SUB
        3'b010: temp_result = a * b;        // MUL (lower 32 bits)
        3'b011: temp_result = (b != 0) ? a / b : 32'b0;  // DIV
        3'b100: temp_result = a << b[4:0];  // SHIFT LEFT
        3'b101: temp_result = a >> b[4:0];  // SHIFT RIGHT
        default: temp_result = 33'b0;
      endcase
      
      result <= temp_result[31:0];
      carry <= temp_result[32];
      zero <= (temp_result[31:0] == 32'b0);
      neg <= temp_result[31];
      overflow <= (op[2:0] == 3'b000) ? // Only for ADD
        ((a[31] == b[31]) && (temp_result[31] != a[31])) : 1'b0;
    end
  end