说明：  常用的单片机子程序库： 目前已有若干版本的子程序库公开发表,它们各有特色。本程序库中的开平方算法为快速逼近算法,它能达到牛顿迭代法同样的精度,而速度加快二十倍左右,超过双字节定点除法的速度。
(Single-chip common subroutine library: there are a number of versions of the subroutine library published, they have their own characteristics. Library in the square root algorithm for fast approximation algorithm that can achieve the same Newton iteration accuracy, and about twenty times faster, more than double the speed of fixed-point division.)