185      * @param int $y
188     abstract public function cmp($x, $y);  argument
192      * @param int $y
195     abstract protected function add($x, $y);  argument
199      * @param int $y
202     abstract protected function mul($x, $y);  argument
206      * @param int $y
209     abstract protected function div($x, $y);  argument
238     function add($x, $y)  argument
240         return bcadd($x, $y);
243     function sub($x, $y)  argument
245         return bcsub($x, $y);
253     function cmp($x, $y)  argument
255         return bccomp($x, $y);
268     function mul($x, $y)  argument
270         return bcmul($x, $y);
273     function div($x, $y)  argument
275         return bcdiv($x, $y);
328     function add($x, $y)  argument
330         return gmp_add($x, $y);
333     function sub($x, $y)  argument
335         return gmp_sub($x, $y);
343     function cmp($x, $y)  argument
345         return gmp_cmp($x, $y);
358     function mul($x, $y)  argument
360         return gmp_mul($x, $y);
363     function div($x, $y)  argument
365         return gmp_div_q($x, $y);