Not that this answers your question, but you might be able to replace

    if (int($fssbCmd{$cmd}{fixed_pattern}) <= 15) {
        $opcode = sprintf("0%x",$<name>Cmd{$cmd}{fixed_pattern});
    } else {
        $opcode = sprintf("%x",$<name>Cmd{$cmd}{fixed_pattern});
    }
[download]

with

    $opcode = sprintf("%02x",$<name>Cmd{$cmd}{fixed_pattern});
[download]

It might help a little bit, anyway.