# Create a buffer containing the binary representation
# of the number we want converted
my $packed = pack("n", 2100);

# unpack to binary
my $bin = unpack("B*", $packed);
print "$bin\n";


##</code><code>##

---
print map { my ($m)=1<<hex($_)&11?' ':'';
$m.=substr('AHJPacehklnorstu',hex($_),1) }
split //,'2fde0abe76c36c914586c';