my @a; $a[ $_ ] = chop $buffer for length($buffer) .. 0;

Unfortunately, "reversed" ranges like length($buffer) .. 0  don't work...

print for 1..3;   # 123
print for 3..1;   # no output
[download]

However, this would work, and is actually pretty fast (about the same as substr):

my @a;
for (my $i=length($buffer)-1; $i>=0; $i--) {
    $a[$i] = chop $buffer;
}

# or

my @a;
my $i = length($buffer);
$a[--$i] = chop $buffer while $i>0;
[download]