OT - Query for bit pattern

If I have a bunch of data where one column in the table is a bitmap, is there
an efficient way to do a query for all the records whose bitmap's first N bits
matches a particular pattern?   Naively, I would store it as an int and do
whatever the sql equivalent of '(hhcode & 0b11110000...) = 0b010100000...)'.
But that is probably horribly inefficient.  Is there a better way?

--
Paul Tomblin <ptomblin@xcski.com> http://blog.xcski.com/
Revenge is an integral part of forgiving and forgetting.
               -- The BOFH