use strict;
use warnings;
use feature "say";

sub hexgroups {
    my ( $n, $group ) = @_;

    die "Can't handle negative $n" if $n <0;

    $group //= 2;                       # default 1 byte = 2 nibbles

    my $nibbles = $n
      ? int( log($n)/log 16**$group ) +1
        : 1  ;                          # 00 has no log

    $nibbles *= $group;                 # zero padding

    my @list = sprintf( '%0*x', $nibbles, $n ) =~ /(.{$group})/g;

    return @list;
}



for my $n (0, map { 2*"1e$_"} 0..10) {
    say "$n => ";
    say "\t"x2, join " ",  hexgroups($n, $_) for 1,2,3,4;
}

##</code><code>##

C:/Strawberry/perl/bin\perl.exe -w d:/tmp/pm/hex_groups.pl 
0 => 
		0
		00
		000
		0000
2 => 
		2
		02
		002
		0002
20 => 
		1 4
		14
		014
		0014
200 => 
		c 8
		c8
		0c8
		00c8
2000 => 
		7 d 0
		07 d0
		7d0
		07d0
20000 => 
		4 e 2 0
		4e 20
		004 e20
		4e20
200000 => 
		3 0 d 4 0
		03 0d 40
		030 d40
		0003 0d40
2000000 => 
		1 e 8 4 8 0
		1e 84 80
		1e8 480
		001e 8480
20000000 => 
		1 3 1 2 d 0 0
		01 31 2d 00
		001 312 d00
		0131 2d00
200000000 => 
		b e b c 2 0 0
		0b eb c2 00
		00b ebc 200
		0beb c200
2000000000 => 
		7 7 3 5 9 4 0 0
		77 35 94 00
		077 359 400
		7735 9400
20000000000 => 
		4 a 8 1 7 c 8 0 0
		04 a8 17 c8 00
		4a8 17c 800
		0004 a817 c800

Compilation finished at Mon Aug 30 16:28:18