Perl Script to reverse a string

Program:

#!/depot/perl-5.8.3/bin/perl

my $str1="Madam i m adaM";
print "ORIGINAL_STRING: $str1 \n";
my $l=length($str1);
my $rev="";
while ($l >0) {
    $l--;
    $rev .= substr($str1,$l,1);
    }
print "REVERSED_STRING: $rev \n";