[PHP-CLI] Big numbers division by 2

<?php
function div_2($n) {
	$m = strlen(strval($n));
	$n = strval($n);
	for ($i = $m - 1; $i >= 0; $i--) {
		$p[$i] += floor($n[$i]/2);
		if ($n[$i]/2-floor($n[$i]/2) != 0) { $p[$i+1] += 5; }
	}
	for ($i = 0; $i < $m; $i++) {
		$str .= $p[$i];
	}
	if ($p[$m] == 5) { $gok = 1; }
	else { $gok = 0; }
	return [$str,$gok];
}
//for $array = div_2($n); with any $n, $array[0] is technically floor($n) whereas $array[1] == $n % 2;
?>