Untitled

`timescale 1ns / 1ps

module LabL5;
    // Declare inputs as reg and outputs as wire
    reg a, b, cin;
    wire z, cout;

    // Instantiate the 1-bit adder
    yAdder1 my_adder(z, cout, a, b, cin);

    // Testbench variables
    reg [2:0] input_combination; // To iterate through all combinations of a, b, cin
    reg [2:0] expected_result;
    integer pass_count, fail_count;

    // Test the adder
    initial begin
        // Initialize counters
        pass_count = 0;
        fail_count = 0;

        // Display header
        $display("a b cin | Expected z cout | Actual z cout  Result");
        $display("-----------------------------------------------|-----------------  -----------  ------");

        // Exhaustive testing
        for (input_combination = 0; input_combination < 8; input_combination = input_combination + 1) begin
            {a, b, cin} = input_combination;

            // Calculate expected sum and carry-out
            expected_result = a + b + cin;
            case (expected_result)
                3'b000: begin
                    expected_result = 3'b000; // z = 0, cout = 0
                end
                3'b001: begin
                    expected_result = 3'b001; // z = 1, cout = 0
                end
                3'b010: begin
                    expected_result = 3'b010; // z = 0, cout = 1
                end
                3'b011: begin
                    expected_result = 3'b011; // z = 1, cout = 1
                end
                3'b100: begin
                    expected_result = 3'b001; // z = 0, cout = 1 (overflow, treated as 2 bits)
                end
                3'b101: begin
                    expected_result = 3'b010; // z = 1, cout = 1 (overflow, treated as 2 bits)
                end
                3'b110: begin
                    expected_result = 3'b011; // z = 0, cout = 1 (overflow, treated as 2 bits)
                end
                3'b111: begin
                    expected_result = 3'b011; // z = 1, cout = 1 (overflow, treated as 2 bits)
                end
            endcase

            #10; // Wait for 10 time units

            // Check if the output is as expected
            if ({z, cout} !== expected_result[1:0]) begin
                fail_count = fail_count + 1;
                $display("%b %b %b | %b %b        | %b %b        FAIL", a, b, cin, expected_result[1], expected_result[0], z, cout);
            end else begin
                pass_count = pass_count + 1;
            end
        end

        // Display summary
        $display("-----------------------------------------------|-----------------  -----------  ------");
        $display("Total Tests: %d", pass_count + fail_count);
        $display("Passed: %d", pass_count);
        $display("Failed: %d", fail_count);

        // Finish simulation
        $finish;
    end
endmodule