203     function pow($base, $exponent)  argument
205         return bcpow($base, $exponent);
238     function _powmod($base, $exponent, $modulus)  argument
242         while($this->cmp($exponent, 0) > 0) {
243             if ($this->mod($exponent, 2)) {
247             $exponent = $this->div($exponent, 2);
252     function powmod($base, $exponent, $modulus)  argument
255             return bcpowmod($base, $exponent, $modulus);
257             return $this->_powmod($base, $exponent, $modulus);
289     function pow($base, $exponent)  argument
291         return gmp_pow($base, $exponent);
319     function powmod($base, $exponent, $modulus)  argument
321         return gmp_powm($base, $exponent, $modulus);