For arbitrary precision mathematics PHP offers the Binary Calculator which supports numbers of any size and precision, represented as strings.
Since PHP 4.0.4, libbcmath is bundled with PHP. You don't need any external libraries for this extension.
In PHP 4, these functions are only available if PHP was configured with --enable-bcmath. In PHP 3, these functions are only available if PHP was NOT configured with --disable-bcmath.
PHP 的 Windows 版本已经内置该扩展模块的支持。您无需加载任何附加的扩展库即可使用这些函数。