binary decomposition

function decomp($n)
{
    $r = [];
    for ($i = 0; $i < PHP_INT_SIZE * 8; ++$i) {
        $x = 2 ** $i;
        if ($x > $n) {
            break;
        } elseif (($n & $x) == $x) {
            $r[] = $x;
        }
    }
    return $r;
}