sub bitextr {
  my $bitstring = shift;
  my $bitnum1 = shift;
  my $bitnum2;

  #Swap the indices if they are high-low
  if( $bitnum1 > $bitnum2 )
  {
    ($bitnum1, $bitnum2 ) = ($bitnum2, $bitnum1 );
  }

  my $size = ($bitnum2-$bitnum1+1);
  print STDERR "size is $size\n";
  my $mask = ("1"x$size);
  print STDERR "mask is $mask\n";
  $mask = unpack( "N*", pack( "B$size", $mask ));
  print STDERR "mask is $mask\n";
  return (($bitstring >> $bitnum1) & ($mask));
}
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