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_idann (
    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 uo_out  = ui_in + uio_in;  // Example: ou_out is the sum of ui_in and uio_in
  assign uio_out[4:2] = 0;
  assign uio_oe = 1;

  // List all unused inputs to prevent warnings
  wire _unused = &{ena, uio_in,  1'b0}; 


wire [9:0] hn0_o, hn1_o, hn2_o, hn3_o, hn4_o, hn5_o, hn6_o, hn7_o;
wire [45:0] loss_o;
wire [22:0] final_o;
wire f0p_o, f1p_o, bp_o;
wire end_check_o;
wire [2:0] curr_state_o;


state_mach sm0 (.clk_i(clk), .rst_i(rst_n), .en_i(1), .init_i(ui_in[7]), .end_check_i(end_check_o),.f0_end_i(1'b0), .f0_pass_o(f0p_o), .f1_pass_o(f1p_o), .b_pass_o(bp_o), .curr_state_o(curr_state_o));

hidden_neuron hn0 (.clk_i(clk), .rst_i(rst_n), .en_i(f0p_o), .x_i(ui_in[3:0]), .w0_i(1), .w1_i(2), .w2_i(3), .w3_i(4), .hidden_neuron_o(hn0_o));

hidden_neuron hn1 (.clk_i(clk), .rst_i(rst_n), .en_i(f0p_o), .x_i(ui_in[3:0]), .w0_i(2), .w1_i(3), .w2_i(4), .w3_i(1), .hidden_neuron_o(hn1_o));

hidden_neuron hn2 (.clk_i(clk), .rst_i(rst_n), .en_i(f0p_o), .x_i(ui_in[3:0]), .w0_i(3), .w1_i(4), .w2_i(1), .w3_i(2), .hidden_neuron_o(hn2_o));

hidden_neuron hn3 (.clk_i(clk), .rst_i(rst_n), .en_i(f0p_o), .x_i(ui_in[3:0]), .w0_i(4), .w1_i(3), .w2_i(1), .w3_i(2), .hidden_neuron_o(hn3_o));

hidden_neuron hn4 (.clk_i(clk), .rst_i(rst_n), .en_i(f0p_o), .x_i(ui_in[3:0]), .w0_i(5), .w1_i(6), .w2_i(7), .w3_i(8), .hidden_neuron_o(hn4_o));

hidden_neuron hn5 (.clk_i(clk), .rst_i(rst_n), .en_i(f0p_o), .x_i(ui_in[3:0]), .w0_i(6), .w1_i(7), .w2_i(8), .w3_i(5), .hidden_neuron_o(hn5_o));

hidden_neuron hn6 (.clk_i(clk), .rst_i(rst_n), .en_i(f0p_o), .x_i(ui_in[3:0]), .w0_i(7), .w1_i(8), .w2_i(5), .w3_i(6), .hidden_neuron_o(hn6_o));

hidden_neuron hn7 (.clk_i(clk), .rst_i(rst_n), .en_i(f0p_o), .x_i(ui_in[3:0]), .w0_i(8), .w1_i(5), .w2_i(6), .w3_i(7), .hidden_neuron_o(hn7_o));

output_neuron on0 (.clk_i(clk), .rst_i(rst_n), .en_i(f0p_o),  .init_i(ui_in[3:0]), .x0_i(hn0_o), .x1_i(hn1_o), .x2_i(hn2_o), .x3_i(hn3_o), .x4_i(hn4_o), .x5_i(hn5_o), .x6_i(hn6_o), .x7_i(hn7_o), .w0_i(1), .w1_i(2), .w2_i(3), .w3_i(4), .w4_i(5), .w5_i(6), .w6_i(7), .w7_i(8), .end_check_o(end_check_o), .loss_o(loss_o), .final_o(final_o));

//INITIALIZED WEIGHTS DIDNT FIT 
// hidden_neuron hn0 (.clk_i(clk), .rst_i(rst_n), .en_i(f0p_o), .x_i(ui_in[3:0]), .w0_i(8'b00100000), .w1_i(8'b00011000), .w2_i(8'b01001010), .w3_i(8'b01100000), .hidden_neuron_o(hn0_o));

// hidden_neuron hn1 (.clk_i(clk), .rst_i(rst_n), .en_i(f0p_o), .x_i(ui_in[3:0]), .w0_i(8'b00001110), .w1_i(8'b00110010), .w2_i(8'b010110000), .w3_i(8'b00000101), .hidden_neuron_o(hn1_o));

// hidden_neuron hn2 (.clk_i(clk), .rst_i(rst_n), .en_i(f0p_o), .x_i(ui_in[3:0]), .w0_i(8'b01111000), .w1_i(8'b01110101), .w2_i(8'b00011010), .w3_i(8'b01011001), .hidden_neuron_o(hn2_o));

// hidden_neuron hn3 (.clk_i(clk), .rst_i(rst_n), .en_i(f0p_o), .x_i(ui_in[3:0]), .w0_i(8'b00011010), .w1_i(8'b00000011), .w2_i(8'b01101101), .w3_i(8'b00111110), .hidden_neuron_o(hn3_o));

// hidden_neuron hn4 (.clk_i(clk), .rst_i(rst_n), .en_i(f0p_o), .x_i(ui_in[3:0]), .w0_i(8'b0010010), .w1_i(8'b01011110), .w2_i(8'b01001110), .w3_i(8'b00110000), .hidden_neuron_o(hn4_o));

// hidden_neuron hn5 (.clk_i(clk), .rst_i(rst_n), .en_i(f0p_o), .x_i(ui_in[3:0]), .w0_i(8'b01010011), .w1_i(8'b00110001), .w2_i(8'b00010010), .w3_i(8'b00110110), .hidden_neuron_o(hn5_o));

// hidden_neuron hn6 (.clk_i(clk), .rst_i(rst_n), .en_i(f0p_o), .x_i(ui_in[3:0]), .w0_i(01001110), .w1_i(8'b00101101), .w2_i(8'b01111000), .w3_i(8'b01010001), .hidden_neuron_o(hn6_o));

// hidden_neuron hn7 (.clk_i(clk), .rst_i(rst_n), .en_i(f0p_o), .x_i(ui_in[3:0]), .w0_i(8'b01010101), .w1_i(8'b01001000), .w2_i(8'b01110110), .w3_i(8'b00000011), .hidden_neuron_o(hn7_o));

// output_neuron on0 (.clk_i(clk), .rst_i(rst_n), .en_i(f0p_o),  .init_i(ui_in[3:0]), .x0_i(hn0_o), .x1_i(hn1_o), .x2_i(hn2_o), .x3_i(hn3_o), .x4_i(hn4_o), .x5_i(hn5_o), .x6_i(hn6_o), .x7_i(hn7_o), .w0_i(8'b00011111), .w1_i(8'b01100000), .w2_i(8'b01111110), .w3_i(8'b00110100), .w4_i(8'b00010001), .w5_i(8'b01101010), .w6_i(8'b01110001), .w7_i(8'b0100100), .end_check_o(end_check_o), .loss_o(loss_o), .final_o(final_o));



//max value output can take on with current weights is 10 bits!
assign uo_out = final_o[7:0];
assign uio_out[1:0] = final_o[9:8];
assign uio_out[7:5] = curr_state_o;


endmodule


module hidden_neuron 
//#(parameter size_p = 4)
(
    input clk_i,
    input rst_i,
    input en_i,
    input [3:0] x_i, 
    //8 bits represent as 1.7 in reality 
    input [7:0] w0_i, 
    input [7:0] w1_i, 
    input [7:0] w2_i, 
    input [7:0] w3_i,   
    //3.7
    output reg [9:0] hidden_neuron_o,
    output reg [31:0] weights_o
);



reg [7:0] wx3, wx2, wx1, wx0;
reg [9:0] neuron_calc;
reg [9:0] hidden_neuron_d, hidden_neuron_q;



always @(*) begin
    wx3 = 0;
    wx2 = 0;
    wx1 = 0;
    wx0 = 0;

    if (x_i[3] == 1'b1) begin
        wx3 = w3_i; 
    end else begin
        wx3 = 0;
    end

    if (x_i[2] == 1'b1) begin
        wx2 = w2_i; 
    end else begin
        wx2 = 0;
    end

    if (x_i[1] == 1'b1) begin
        wx1 = w1_i; 
    end else begin
        wx1 = 0;
    end

    if (x_i[0] == 1'b1) begin
        wx0 = w0_i; 
    end else begin
        wx0 = 0;
    end

    neuron_calc = wx3 + wx2 + wx1 + wx0;

    //ACTIVATION FUNCTION LOGIC (relu), considering my weights are 0 - 1 range, i wont have any negative numbers anyway tho lol
    if (neuron_calc <= 0) begin
        hidden_neuron_d = 0;
    end else begin
        hidden_neuron_d = neuron_calc;
    end

end

always @(posedge clk_i) begin 
    if (!rst_i) begin
        hidden_neuron_q <= 0;
    end else if (en_i) begin
        hidden_neuron_q <= hidden_neuron_d;
    end
end

assign hidden_neuron_o = hidden_neuron_q;

always @(posedge clk_i) begin
    if (!rst_i) begin
        weights_o <= 0; 
    end else if (en_i) begin
        weights_o <= {w3_i, w2_i, w1_i, w0_i}; 
    end
end 



endmodule

    module output_neuron 
    (
        input clk_i,
        input rst_i,
        input en_i,
        input [3:0] init_i,
        input [9:0] x0_i,
        input [9:0] x1_i,
        input [9:0] x2_i,
        input [9:0] x3_i,
        input [9:0] x4_i,
        input [9:0] x5_i,
        input [9:0] x6_i,
        input [9:0] x7_i,
        //7:0 is fixed point: 1.7 form for interpretaion 
        input [7:0] w0_i,
        input [7:0] w1_i,
        input [7:0] w2_i,
        input [7:0] w3_i,
        input [7:0] w4_i,
        input [7:0] w5_i,
        input [7:0] w6_i,
        input [7:0] w7_i,
        //output fwrd_done_o,
        //output f0_end_o, 
        //output f1_end_o,
        output reg  [45:0] loss_o,
        output reg [22:0] final_o,
        output reg end_check_o
    );

wire [9:0] w0_ext, w1_ext, w2_ext, w3_ext, w4_ext, w5_ext, w6_ext, w7_ext;
reg [22:0] final_d, final_q; 

//unsure if yosys will zero extend when i do multiplication, so im doing this to be safe 
assign w0_ext = {2'b0, w0_i};
assign w1_ext = {2'b0, w1_i};
assign w2_ext = {2'b0, w2_i};
assign w3_ext = {2'b0, w3_i};
assign w4_ext = {2'b0, w4_i};
assign w5_ext = {2'b0, w5_i};
assign w6_ext = {2'b0, w6_i};
assign w7_ext = {2'b0, w7_i};

always @(*) begin
    final_d = (x0_i * w0_ext) + (x1_i * w1_ext) +  (x2_i * w2_ext) + (x3_i * w3_ext) +  (x4_i * w4_ext) + (x5_i * w5_ext) + (x6_i * w6_ext) + (x7_i * w7_ext); 
    
end

always @(posedge clk_i or negedge rst_i) begin
    if (!rst_i) begin
        final_q <= 0; 
    end else if (en_i) begin
        final_q <= final_d;
    end
end

assign end_check_o = ((final_q == 0) && (init_i == 0));

assign final_o = final_q;

//LOSS FUNCTION 
wire [22:0] target_ext;
reg signed [22:0] inner_fn;
reg [45:0] loss_d;

assign target_ext = {19'b00000000000000000, init_i};

always @(*) begin
    inner_fn = (final_q - target_ext);
    loss_d = inner_fn * inner_fn;
end

always @(posedge clk_i) begin
    if (!rst_i) begin
        loss_o <= 0; 
    end else if (en_i && (final_q != 0)) begin
        loss_o <= loss_d;
    end
end


//wire [45:0] loss_check;
//loss_calc mse_fn (.clk_i(clk_i), .rst_i(rst_i), .en_i (en_i), .target_i(init_i), .predicted_i(final_q), .loss_o(loss_o));


endmodule

module state_mach
(
    input clk_i,
    input rst_i,
    //enable will just be 1
    input en_i,
    input init_i,
    input f0_end_i,
    input end_check_i,
    //reg?
    output reg f0_pass_o,
    output reg f1_pass_o,
    output reg b_pass_o,
    output reg [2:0] curr_state_o
);
// >>> Module Implementation Begin

// <<< Module Implementation End
endmodule



Reference solution:
rtl/generated.v: 
reg [2:0] state_d, state_q;
always @(posedge clk_i) begin
    if (!rst_i) begin
        state_q <= 3'b000;
    end else if (en_i) begin
        state_q <= state_d;
    end
end

always @(*) begin
    state_d = state_q;

    case (state_q)
        //init
        3'b000 : begin
            f0_pass_o = 0;
            f1_pass_o = 0;
            b_pass_o = 0;

            if (init_i == 1'b1) begin
                state_d = 3'b001;
            end

        end
        
        //f0 pass
        3'b001 : begin
            f0_pass_o = 1;
            f1_pass_o = 0;
            b_pass_o = 0;

            if (end_check_i == 1'b1) begin
                state_d = 3'b010;
            end
        end

    //end
        3'b010 : begin
            f0_pass_o = 0;
            f1_pass_o = 0;
            b_pass_o = 0;
        end


        default: begin
            state_d = 3'b000;
            if (f0_end_i == 1'b1) begin
                state_d = 3'b010;
            end
        end
    endcase

end

assign curr_state_o = state_q;