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) 2025 Matthew Chen, Jovan Koledin, Ryan Leahy
 * SPDX-License-Identifier: Apache-2.0
 */

`default_nettype none

module crossyroad  (
    input clk,          // System clock
    input rst_man,      // Reset signal
    input move_btn,      // Button input for scrolling
    output hsync,       // Horizontal sync for VGA
    output vsync,       // Vertical sync for VGA
    output [2:0] rgb
);

    // VGA Resolution
    localparam SCREEN_WIDTH = 640;
    //localparam SCREEN_HEIGHT = 480;
    //localparam SCORE_WIDTH = 640;
    //localparam SCORE_HEIGHT = 32;
    localparam OBSTACLE_WIDTH = 120;
    localparam OBSTACLE_HEIGHT = 70;
    localparam CHICKEN_X = 310;
    localparam CHICKEN_Y = 420;
    localparam CHICKEN_WIDTH = 30;
    localparam CHICKEN_HEIGHT = 40;
    localparam OB_Y_OFFSET = 10'd160;
    localparam OB_X_OFFSET = 10'd200;


    // Internal signals
    wire [9:0] pixel_x, pixel_y; // VGA pixel coordinates
    wire [9:0] obstacle1_y, obstacle2_y, obstacle3_y;       // Obstacle Y position
    wire [9:0] obstacle1_x, obstacle2_x, obstacle3_x;       // Obstacle X position (Corrected typo)
    wire [6:0] score;
    wire [2:0] score_rgb;
    wire move_h, move_v;
    wire rst;
    wire video_on;            // VGA video enable

    // VGA Controller Instance
    vga vga_inst (
        .clk(clk),
        .reset(rst_man), // The VGA controller does not need to be reset when the game restarts.
        .hsync(hsync),
        .vsync(vsync),
        .display_on(video_on),
        .hpos(pixel_x),
        .vpos(pixel_y)
    );

    scroll_v scroll1_v_inst (
        .clk(clk),
        .reset(rst),
        .move_btn(move_btn),
        .move_followers(move_v),
        .score(score),
        .y_pos(obstacle1_y)
    );

    scroll_h scroll1_h_inst (
        .clk(clk),
        .move_followers(move_h),
        .reset(rst),
        .score(score),
        .h_pos(obstacle1_x)
    );
  
     scroll_v_follower scroll2_v_inst (
        .clk(clk),
        .reset(rst),
        .move(move_v),
        .start_posy(0),
        .y_pos(obstacle2_y)
    );

    scroll_h_follower scroll2_h_inst (
        .clk(clk),
        .reset(rst),
        .move(move_h),
        .start_posx(SCREEN_WIDTH),
        .h_pos(obstacle2_x)
    );

    
    scroll_v_follower scroll3_v_inst (
        .clk(clk),
        .reset(rst),
        .move(move_v),
        .start_posy(OB_Y_OFFSET << 1),
        .y_pos(obstacle3_y)
    );

    scroll_h_follower scroll3_h_inst (
        .clk(clk),
        .reset(rst),
        .move(move_h),
        .start_posx(OB_X_OFFSET << 1),
        .h_pos(obstacle3_x)
    );
    
    
    score score_inst(
        .i_clk(clk),
        .i_rst_n(~rst),
        .i_vpos(pixel_y),
        .i_hpos(pixel_x),
        .i_score(score),
        .o_score_rgb(score_rgb)
    );
    
    // VGA Display & Collision Logic (Optimized)
    wire obstacle1_hit = (pixel_x >= obstacle1_x) && (pixel_x < obstacle1_x + OBSTACLE_WIDTH) &&
                         (pixel_y >= obstacle1_y) && (pixel_y < obstacle1_y + OBSTACLE_HEIGHT);

    // VGA Display & Collision Logic for the second obstacle
    wire obstacle2_hit = (pixel_x >= obstacle2_x) && (pixel_x < obstacle2_x + OBSTACLE_WIDTH) &&
                         (pixel_y >= obstacle2_y) && (pixel_y < obstacle2_y + OBSTACLE_HEIGHT);
    
    // VGA Display & Collision Logic for the third obstacle
    wire obstacle3_hit = (pixel_x >= obstacle3_x) && (pixel_x < obstacle3_x + OBSTACLE_WIDTH) &&
                         (pixel_y >= obstacle3_y) && (pixel_y < obstacle3_y + OBSTACLE_HEIGHT);
    
    // Check if vga scan hits chicken location
    wire chicken_hit = (pixel_x >= CHICKEN_X) && (pixel_x < CHICKEN_X + CHICKEN_WIDTH) &&
                       (pixel_y >= CHICKEN_Y) && (pixel_y < CHICKEN_Y + CHICKEN_HEIGHT);

    assign rgb = (video_on) ?
                    (score_rgb != 3'b000) ? score_rgb : // If score_rbg is not black. Draw it.
                    (obstacle1_hit) ? 3'b001 :           // Obstacle (Red)
                    (obstacle2_hit) ? 3'b001 :           // Obstacle (Red)
                    (obstacle3_hit) ? 3'b001 :           // Obstacle (Red)
                    (chicken_hit) ? 3'b010 :            // Chicken (Green)
                    3'b100 :                          // Background (Blue)
                 3'b000;                           // Blanking (Black)

    wire rst_collision = (obstacle1_hit || obstacle2_hit || obstacle3_hit) && chicken_hit; // If collision activate reset
    assign rst = rst_man | rst_collision;

endmodule

/*
 * Copyright (c) 2025 Matthew Chen, Jovan Koledin, Ryan Leahy
 * SPDX-License-Identifier: Apache-2.0
 */
`default_nettype none

// Calculate and render score, score increments while user holds move button
module score #(
    parameter SCORE_BACKGROUND_HEIGHT = 32,
    parameter SCORE_WIDTH = 12,
    parameter SCORE_GAP = 4,
    parameter SCORE_HORIZONTAL_START_OFFSET = 606,
    parameter SCORE_VERTICAL_START_OFFSET = 2,
    parameter BANNER_COLOR = 3'b000, // WARNING: Black means no draw
    parameter DIGIT_COLOR  = 3'b111
)
(
    input wire i_clk,
    input wire i_rst_n,
    input wire [9:0] i_vpos,
    input wire [9:0] i_hpos,
    input wire [6:0] i_score,

    output wire [2:0] o_score_rgb
);

    wire [1:0] w_current_digits_place;
    wire [9:0] w_digit_horizontal_offset;

    wire w_digit_geometries[8:0];

    wire w_digit[9:0];

    reg [2:0] r_score_rgb;

    /**
     * Determines which Nth place should be currently drawn on the screen for the score
     * given the horizontal position.
     *
     * Also indicates when the horizontal position is not in a place to draw the score.
    */
    assign w_current_digits_place = (i_hpos >= SCORE_HORIZONTAL_START_OFFSET &&
                                     i_hpos <  SCORE_HORIZONTAL_START_OFFSET + SCORE_WIDTH) ? 
                                        2'd1 : // 10's place
                                    (i_hpos >= SCORE_HORIZONTAL_START_OFFSET + SCORE_WIDTH + SCORE_GAP &&
                                     i_hpos <  SCORE_HORIZONTAL_START_OFFSET + 2*SCORE_WIDTH + SCORE_GAP) ?
                                        2'd0 : // 1's place
                                        2'd2;  // Not in digit section.

    /**
     * Sets the horizontal draw offset for the score digits taking into account the Nth place horizontal position.
    */
    assign w_digit_horizontal_offset = (w_current_digits_place == 2'd1) ?
                                        SCORE_HORIZONTAL_START_OFFSET : // 10's place horizontal offset
                                        SCORE_HORIZONTAL_START_OFFSET + SCORE_WIDTH + SCORE_GAP; // 1's place horizontal offset

    /**
     * The digits 0-9 are composed of different combinations of 9 geometrical shapes that overlap.
     *
     * In the docs directory, you can find an image showing these geometries represented as different colors.
    */
    // RED
    assign w_digit_geometries[0] = (i_vpos >= SCORE_VERTICAL_START_OFFSET      && i_vpos < SCORE_VERTICAL_START_OFFSET +  4) &&
                                   (i_hpos >= w_digit_horizontal_offset        && i_hpos < w_digit_horizontal_offset   +  8);

    // CYAN
    assign w_digit_geometries[1] = (i_vpos >= SCORE_VERTICAL_START_OFFSET      && i_vpos < SCORE_VERTICAL_START_OFFSET + 16) &&
                                   (i_hpos >= w_digit_horizontal_offset        && i_hpos < w_digit_horizontal_offset   +  4);

    // MAGENTA
    assign w_digit_geometries[2] = (i_vpos >= SCORE_VERTICAL_START_OFFSET + 16 && i_vpos < SCORE_VERTICAL_START_OFFSET + 24) &&
                                   (i_hpos >= w_digit_horizontal_offset        && i_hpos < w_digit_horizontal_offset   +  4);

    // YELLOW
    assign w_digit_geometries[3] = (i_vpos >= SCORE_VERTICAL_START_OFFSET + 24 && i_vpos < SCORE_VERTICAL_START_OFFSET + 28) &&
                                   (i_hpos >= w_digit_horizontal_offset        && i_hpos < w_digit_horizontal_offset   + 12);

    // PURPLE
    assign w_digit_geometries[4] = (i_vpos >= SCORE_VERTICAL_START_OFFSET + 16 && i_vpos < SCORE_VERTICAL_START_OFFSET + 28) &&
                                   (i_hpos >= w_digit_horizontal_offset   +  8 && i_hpos < w_digit_horizontal_offset   + 12);

    // BLUE
    assign w_digit_geometries[5] = (i_vpos >= SCORE_VERTICAL_START_OFFSET      && i_vpos < SCORE_VERTICAL_START_OFFSET + 16) &&
                                   (i_hpos >= w_digit_horizontal_offset   +  8 && i_hpos < w_digit_horizontal_offset   + 12);

    // GREEN
    assign w_digit_geometries[6] = (i_vpos >= SCORE_VERTICAL_START_OFFSET + 12 && i_vpos < SCORE_VERTICAL_START_OFFSET + 16) &&
                                   (i_hpos >= w_digit_horizontal_offset        && i_hpos < w_digit_horizontal_offset   + 12);

    // ORANGE
    assign w_digit_geometries[7] = (i_vpos >= SCORE_VERTICAL_START_OFFSET +  4 && i_vpos < SCORE_VERTICAL_START_OFFSET + 24) &&
                                   (i_hpos >= w_digit_horizontal_offset   +  4 && i_hpos < w_digit_horizontal_offset   +  8);

    // BLACK
    assign w_digit_geometries[8] = (i_vpos >= SCORE_VERTICAL_START_OFFSET      && i_vpos < SCORE_VERTICAL_START_OFFSET +  4) &&
                                   (i_hpos >= w_digit_horizontal_offset   +  8 && i_hpos < w_digit_horizontal_offset   + 12);

    /**
     * In the doc directory, you can find an image showing the different geometries that compose the digits.
    */
    assign w_digit[0] = w_digit_geometries[0] || w_digit_geometries[1] || w_digit_geometries[2] || w_digit_geometries[3] ||
                        w_digit_geometries[4] || w_digit_geometries[5];

    assign w_digit[1] = w_digit_geometries[0] || w_digit_geometries[7] || w_digit_geometries[3];


    assign w_digit[2] = w_digit_geometries[0] || w_digit_geometries[5] || w_digit_geometries[6] || w_digit_geometries[2] ||
                        w_digit_geometries[3];

    assign w_digit[3] = w_digit_geometries[0] || w_digit_geometries[5] || w_digit_geometries[6] || w_digit_geometries[4] ||
                        w_digit_geometries[3];

    assign w_digit[4] = w_digit_geometries[1] || w_digit_geometries[6] || w_digit_geometries[5] || w_digit_geometries[4];


    assign w_digit[5] = w_digit_geometries[8] || w_digit_geometries[0] || w_digit_geometries[1] || w_digit_geometries[6] ||
                        w_digit_geometries[4] || w_digit_geometries[3];

    assign w_digit[6] = w_digit_geometries[8] || w_digit_geometries[0] || w_digit_geometries[1] || w_digit_geometries[6] ||
                        w_digit_geometries[4] || w_digit_geometries[3] || w_digit_geometries[2];

    assign w_digit[7] = w_digit_geometries[0] || w_digit_geometries[5] || w_digit_geometries[4];


    assign w_digit[8] = w_digit_geometries[8] || w_digit_geometries[0] || w_digit_geometries[1] || w_digit_geometries[6] ||
                        w_digit_geometries[4] || w_digit_geometries[3] || w_digit_geometries[2] || w_digit_geometries[5];

    assign w_digit[9] = w_digit_geometries[8] || w_digit_geometries[0] || w_digit_geometries[1] || w_digit_geometries[6] ||
                        w_digit_geometries[4] || w_digit_geometries[5];

    assign o_score_rgb = r_score_rgb;

always @(posedge i_clk) begin
    if (i_rst_n && i_vpos <= SCORE_BACKGROUND_HEIGHT) begin
        if (w_current_digits_place == 2'd1) begin // Draw 10's place digit
            r_score_rgb <= (w_digit[(i_score / 10) % 10]) ? DIGIT_COLOR : BANNER_COLOR;
        end
        else if (w_current_digits_place == 2'd0) begin // Draw 1's place digit
            r_score_rgb <= (w_digit[(i_score) % 10]) ? DIGIT_COLOR : BANNER_COLOR;
        end
        else
            r_score_rgb <= BANNER_COLOR;
    end
    else begin
        r_score_rgb <= 3'b000; // WARNING: Black means no draw
    end
end

endmodule


module scroll_h (
    output reg [9:0] h_pos, // Counter for scrolling down
    output reg move_followers, //Tells other obstacles when to move
    input wire reset,
    input wire [6:0] score,
    input wire clk
);

  
    // Parameters
    localparam move_amt = 2;           // Move amount per 40ms
    localparam SCREEN_WIDTH = 640;    // Screen height
    localparam SPEED = 100000;         // 40ms at 25MHz clock

    // Internal Registers
    reg [17:0] ctr;                    // Counter for timing

    // Obstacle Movement Logic
    always @(posedge clk) begin
        if (reset) begin
            h_pos <= 10'd380;                // Reset position to top
            ctr <= 0;                  // Reset counter
            move_followers <= 0;
        end else begin
            ctr <= ctr + 1;
            if (ctr >= (SPEED)) begin
                move_followers <= 1;
                ctr <= {11'b0, score} << 9; // Increase speed as score increases
                if ((h_pos + move_amt) >= SCREEN_WIDTH) begin
                    h_pos <= 0;
                end else begin
                    h_pos <= h_pos + move_amt;
                end 
            end else
                move_followers <= 0;
        end
    end
endmodule

module scroll_v (
    output reg [9:0] y_pos, // Counter for scrolling down
    output reg [6:0] score,
    output reg move_followers, // Tells follower obstacles to move 
    input wire move_btn,
    input wire reset,
    input wire clk
);

    // Parameters
    localparam move_amt = 2;           // Move amount per 40ms
    localparam SCREEN_HEIGHT = 480;    // Screen height
    localparam SPEED = 100000;          // 40ms at 25MHz clock
    localparam SCORE_SPEED = 70;       // 1s score update
    localparam OB_Y_OFFSET = 10'd150;

    // Internal Registers
    reg [17:0] ctr;                    // Counter for timing
    reg [6:0] score_ctr;

    // Obstacle Movement Logic
    always @(posedge clk) begin
        if (reset) begin
            y_pos <= OB_Y_OFFSET;        // Reset position to top
            ctr <= 0;                  // Reset counter
            score_ctr <= 0;
            score <= 0;
            move_followers <= 0;
        end else begin

            // Counter for speed control
            if (move_btn) begin
                ctr <= ctr + 1;
                if (ctr >= SPEED) begin
                    move_followers <= 1;
                    ctr <= 0;
                    score_ctr <= score_ctr + 1; 
                    if ((y_pos + move_amt) >= SCREEN_HEIGHT) begin
                        y_pos <= 0;
                    end else begin
                        y_pos <= y_pos + move_amt;
                    end    
                end else
                  move_followers <= 0;
                if (score_ctr == SCORE_SPEED) begin
                    score_ctr <= 0;
                    if(score < 99)
                        score <= score + 1;
                end
            end else begin
                move_followers <= 0;
            end
        end
    end

endmodule

module scroll_h_follower (
    output reg [9:0] h_pos, // Counter for scrolling down
    input wire reset,
    input wire [9:0] start_posx,
    input wire move,
    input wire clk
);
// >>> Module Implementation Begin

// <<< Module Implementation End
endmodule



module scroll_v_follower (
    output reg [9:0] y_pos, // Counter for scrolling down
    input wire [9:0] start_posy,
    input wire move, // scroll_v tells when to move
    input wire reset,
    input wire clk
);

    // Parameters
    localparam move_amt = 2;           // Move amount per 40ms
    localparam SCREEN_HEIGHT = 480;    // Screen height
  
    // Obstacle Movement Logic
    always @(posedge clk) begin
        if (reset) begin
            y_pos <= start_posy;        // Reset position to top
        end else begin
          if (move) begin
              if ((y_pos + move_amt) >= SCREEN_HEIGHT) begin
                  y_pos <= 0;
              end else begin
                  y_pos <= y_pos + move_amt;
              end    
          end
        end
    end

endmodule

/*
 * Copyright (c) 2025 Matthew Chen, Jovan Koledin, Ryan Leahy
 * SPDX-License-Identifier: Apache-2.0
 */


`ifndef HVSYNC_GENERATOR_H
`define HVSYNC_GENERATOR_H

module vga (
    output reg [9:0] vpos,
    output reg [9:0] hpos,
    output reg vsync,
    output reg hsync,
    output display_on,

    input reset,
    input clk
);

    // declarations for TV-simulator sync parameters
    // horizontal constants
    parameter H_DISPLAY       = 640; // horizontal display width
    parameter H_BACK          =  48; // horizontal left border (back porch)
    parameter H_FRONT         =  16; // horizontal right border (front porch)
    parameter H_SYNC          =  96; // horizontal sync width
    // vertical constants
    parameter V_DISPLAY       = 480; // vertical display height
    parameter V_TOP           =  33; // vertical top border
    parameter V_BOTTOM        =  10; // vertical bottom border
    parameter V_SYNC          =   2; // vertical sync # lines
    // derived constants
    parameter H_SYNC_START    = H_DISPLAY + H_FRONT;
    parameter H_SYNC_END      = H_DISPLAY + H_FRONT + H_SYNC - 1;
    parameter H_MAX           = H_DISPLAY + H_BACK + H_FRONT + H_SYNC - 1;
    parameter V_SYNC_START    = V_DISPLAY + V_BOTTOM;
    parameter V_SYNC_END      = V_DISPLAY + V_BOTTOM + V_SYNC - 1;
    parameter V_MAX           = V_DISPLAY + V_TOP + V_BOTTOM + V_SYNC - 1;

    wire hmaxxed = (hpos == H_MAX) || reset; // set when hpos is maximum
    wire vmaxxed = (vpos == V_MAX) || reset; // set when vpos is maximum

    // position counter
    always @(posedge clk)
    begin
        if(hmaxxed) begin
            if(vmaxxed)
                vpos <= 0;
            else
                vpos <= vpos + 1;
            hpos <= 0;
        end 
        else begin
            hpos <= hpos + 1;
        end
        hsync <= (hpos >= H_SYNC_START && hpos <= H_SYNC_END);
        vsync <= (vpos >= V_SYNC_START && vpos <= V_SYNC_END);
    end

    // display_on is set when beam is in "safe" visible frame
    assign display_on = (hpos < H_DISPLAY) && (vpos < V_DISPLAY);

endmodule

`endif


/*
 * Copyright (c) 2025 Matthew Chen, Jovan Koledin, Ryan Leahy
 * SPDX-License-Identifier: Apache-2.0
 */

`default_nettype none

module tt_um_10_vga_crossyroad (
    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
);

  wire hsync, vsync;
  wire [2:0] rgb;
  wire unused;
  wire [7:0] unused_8;
  wire [6:0] unused_7;

  crossyroad game1 (
    .clk(clk),          // System clock
    .rst_man(!rst_n),      // Reset signal
    .move_btn(ui_in[0]),      // Button input for scrolling
    .hsync(hsync),       // Horizontal sync for VGA
    .vsync(vsync),       // Vertical sync for VGA
    .rgb(rgb)
  );
  
  /*
  uo_out Pinout:

  uo_out[0] - R1
  uo_out[1] - G1
  uo_out[2] - B1
  uo_out[3] - vsync
  uo_out[4] - R0
  uo_out[5] - G0
  uo_out[6] - B0
  uo_out[7] - hsync
  */
  assign uo_out = {hsync, rgb[0], rgb[1], rgb[2], vsync, rgb[0], rgb[1], rgb[2]};
  // All output/input pins must be assigned. If not used, assign to 0.
  assign uio_out = 0;
  assign uio_oe  = 0;
  assign unused = ena;
  assign unused_8 = uio_in;
  assign unused_7 = ui_in[7:1];

endmodule

Reference solution:
rtl/generated.v: 
    // Parameters
    localparam move_amt = 2;           // Move amount per 40ms
    localparam SCREEN_WIDTH = 640;    // Screen height

    // Obstacle Movement Logic
    always @(posedge clk) begin
        if (reset) begin
            h_pos <= start_posx;                // Reset position to top
        end else begin
            if (move) begin
              if ((h_pos - move_amt) <= 0) begin
                    h_pos <= SCREEN_WIDTH;
                end else begin
                    h_pos <= h_pos - move_amt;
                end 
            end
        end
    end