private static int getScale(Environment env) {
        Memory value = env.getConfigValue("bcmath.scale");
        return value == null ? 0 : value.toInteger();
    }
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