Okay, the C programmer in me rebelled against the inefficiency of my earlier reply. How about: 
sub b5ToInt {
  use integer;
  return     ($_[4]||0)
          + (($_[3]||0)<<6)
          + (($_[2]||0)<<12)
          + (($_[1]||0)<<18)
          + (($_[0]||0)<<24);
}
sub intToB5 {
  use integer;
  my $in = int(shift);
  return map { $_ & 0b111111 } 
   (($in >> 24),
    ($in >> 18),
    ($in >> 12),
    ($in >>  6),
    $in);
}

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In reply to Re^2: 5x6-bit values into/out of a 32-bit word by Thelonius
in thread 5x6-bit values into/out of a 32-bit word by BrowserUk

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