`timescale 1ns/1ps

module alu_tb;

    reg [7:0] A;
    reg [7:0] B;
    reg [2:0] sel;
    wire [7:0] Y;
    wire zero;
    wire carry;

    alu uut (
        .A(A),
        .B(B),
        .sel(sel),
        .Y(Y),
        .zero(zero),
        .carry(carry)
    );

    initial begin
        A = 8'd10;
        B = 8'd5;

        sel = 3'b000; #10;   // A + B = 15
        sel = 3'b001; #10;   // A - B = 5
        sel = 3'b010; #10;   // A AND B
        sel = 3'b011; #10;   // A OR B
        sel = 3'b100; #10;   // A XOR B
        sel = 3'b101; #10;   // NOT A
        sel = 3'b110; #10;   // A << 1
        sel = 3'b111; #10;   // A >> 1

        // test carry kod sabiranja
        A = 8'hFF;
        B = 8'h01;
        sel = 3'b000; #10;   // carry = 1, Y = 00, zero = 1

        // test zero kod oduzimanja
        A = 8'd20;
        B = 8'd20;
        sel = 3'b001; #10;   // Y = 00, zero = 1

        #10;
        $stop;
    end

endmodule