104     private static function checkInstance(self $x, self $y)  argument
106         if ($x->instanceID != $y->instanceID) {
116     public function equals(self $x)  argument
118         static::checkInstance($this, $x);
120         return $this->value == $x->value;
128     public function compare(self $x)  argument
130         static::checkInstance($this, $x);
133         $b = $x->value;
146      * @param string $x
149     private static function deg($x)  argument
151         $x = ltrim($x, "\0");
152         $xbit = decbin(ord($x[0]));
154         $len = strlen($x);
158         return 8 * strlen($x) - 9 + $xlen;
167     private static function polynomialDivide($x, $y)  argument
174         $r = $x;
197     private static function regularPolynomialMultiply($x, $y)  argument
199         $precomputed = [ltrim($x, "\0")];
200         $x = strrev(BinaryField::base256ToBase2($x));
202         if (strlen($x) == strlen($y)) {
203             $length = strlen($x);
205             $length = max(strlen($x), strlen($y));
206             $x = str_pad($x, $length, '0');
212         $x = strrev($x);
216             $precomputed[$i] = BinaryField::base2ToBase256($x . str_repeat('0', $i));
236     private static function polynomialMultiply($x, $y)  argument
238         if (strlen($x) == strlen($y)) {
239             $length = strlen($x);
241             $length = max(strlen($x), strlen($y));
242             $x = str_pad($x, $length, "\0", STR_PAD_LEFT);
249 …        self::subMultiply(str_pad($x, 4, "\0", STR_PAD_LEFT), str_pad($y, 4, "\0", STR_PAD_LEFT)) :
250                     self::subMultiply($x, $y);
252                 return self::regularPolynomialMultiply($x, $y);
257         $x1 = substr($x, 0, -$m);
258         $x0 = substr($x, -$m);
284      * @param string $x
289     private static function subMultiply($x, $y)  argument
291         $x = unpack('N', $x)[1];
294         $x0 = $x & 0x11111111;
295         $x1 = $x & 0x22222222;
296         $x2 = $x & 0x44444444;
297         $x3 = $x & 0x88888888;
322      * @param string $x
326     private static function subAdd2($x, $y)  argument
328         $length = max(strlen($x), strlen($y));
329         $x = str_pad($x, $length, "\0", STR_PAD_LEFT);
331         return $x ^ $y;
337      * @param string $x
341     private static function subAdd3($x, $y, $z)  argument
343         $length = max(strlen($x), strlen($y), strlen($z));
344         $x = str_pad($x, $length, "\0", STR_PAD_LEFT);
347         return $x ^ $y ^ $z;
361         $x = str_pad($this->value, $length, "\0", STR_PAD_LEFT);
364         return new static($this->instanceID, $x ^ $y);
372     public function subtract(self $x)  argument
374         return $this->add($x);
429     public function divide(self $x)  argument
431         static::checkInstance($this, $x);
433         $x = $x->modInverse();
434         return $this->multiply($x);
447         $x = str_pad($this->value, strlen(static::$modulo[$this->instanceID]), "\0", STR_PAD_LEFT);
449         return new static($this->instanceID, $x ^ static::$modulo[$this->instanceID]);