public override void SetBottom(int bottom)
{
bottomSlot = bottom;
if (readerGen[bottom] != currentReaderGen)
{
Convert(bottomSlot);
}
bottomOrd = ords[bottom];
System.Diagnostics.Debug.Assert(bottomOrd >= 0);
System.Diagnostics.Debug.Assert(bottomOrd < lookup.Length);
bottomValue = values[bottom];
}