pack('q>', $_);  # Signed
pack('Q>', $_);  # Unsigned

##</code><code>##

pack('NN', $_<0 ? -1 : 0, $_);  # Signed
pack('NN', 0, $_);              # Unsigned

##</code><code>##

sprintf('%8X', $_);   # Padded with spaces
sprintf('%08X', $_);  # Padded with zeros