$var = 0x3000;
if ($var <= 0x100) {
  description {
    base = $var;
    id   = "uniqe_identifier";
    text = "This is the first element with base = $var\n";
  }
} elsif ($var <= 0x200) {
  $basevar = $var - 0xF;
  description {
    base = $basevar;
    id   = "uniqe_identifier";
    text = "This is the first element with base = $basevar\n";
  }
} else {
  $basevar = $var - 0x1F;
  description {
    base = $basevar;
    id   = "uniqe_identifier";
    text = "This is the first element with base = $basevar\n";
  }
}