module tb1wallace; // random unsigned inputs, decimal values including a check

reg  [7:0] p0, p1, p2, p3, p4, p5;  // 8-bit inputs (to be chosen randomly)
wire [8:0] s;                       // 9-bit sum output
wire [9:1] c;                       // 9-bit carry output
reg  [10:0] sval, check;            // 11-bit final sum and check values

// instantiate the 6-input Wallace tree
wallace wallace1(p0, p1, p2, p3, p4, p5, s, c);

// simulation of 50 random addition operations
initial repeat (50) begin
    // get new operand values and compute a check value
    p0 = $random; p1 = $random; p2 = $random;
    p3 = $random; p4 = $random; p5 = $random;
    check = p0 + p1 + p2 + p3 + p4 + p5;

    // compute and display the final sum value every 10 time units
    #10 sval = s + (2*c);
    $display($time, "  %d + %d + %d + %d + %d + %d = %d (%d)",
             p0, p1, p2, p3, p4, p5, sval, check);
end

endmodule