if you treat this everyday, the better way is to create a template:

use strict;
use warnings;
use Convert::Binary::C;
use Data::Dumper;
use Data::Hexdumper;
my $c = Convert::Binary::C->new(ByteOrder => 'BigEndian', LongSize  =>
+ 8)->parse(<<'ENDC');
struct one8 {
        unsigned long a;
};
struct two4 {
        unsigned int a;
        unsigned int b;
};
ENDC

my $data = "\x91\x34\x33\x90\x81\x32\x31\x80";
print hexdump($data);
print "BigEndian\n";
my $u1 = $c->unpack('one8', $data);
print Dumper $u1;
my $u2 = $c->unpack('two4', $data);
print Dumper $u2;
print "LittleEndian\n";
$c->tag('one8', ByteOrder => 'LittleEndian');
$c->tag('two4', ByteOrder => 'LittleEndian');
my $u3 = $c->unpack('one8', $data);
print Dumper $u3;
my $u4 = $c->unpack('two4', $data);
print Dumper $u4;
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