public static Memory bcadd(Environment env, Memory left, Memory right) {
        return bcadd(env, left, right, getScale(env));
    }
bcmath extension
http://www.php.net/manual/ru/book.bc.php
exts/jphp-zend-ext/src/main/java/org/develnext/jphp/zend/ext/standard/BCMathFunctions.java