my $lo_pos = binary_search(0,$#F,$lo,\&reader,\@F,2);
my $hi_pos = binary_search($lo_pos,$#F,$hi,\&reader,\@F,2);

##</code><code>##

Did 6 probes for low
Did 6 probes for high
32,33,34,35
Did 6 probes for low
Did 7 probes for high
50,51,52,53,54,55,56,57,58,59,60,61,62,63,64