Generate v6 subnet mask for each section per cidr

gen_v6_subnet_numbers.php

<?php
for ($cidr = 0; $cidr <= 128; $cidr++) {
    $maskvalue = [];
    $imaskvalue = [];
    $netaddr = [];
    for ($i = 0; $i < 8; $i++) {
        $maskbit = $cidr - ($i * 16);
        if ($maskbit < 0) $maskbit = 0;
        if ($maskbit > 16) $maskbit = 16;

        $maskbitstr = str_pad(str_repeat('1', $maskbit), 16, '0');

        $maskvalue[$i] = intval(bindec($maskbitstr));
        $imaskvalue[$i] = abs($maskvalue[$i] - 65535);
    }
}