log2的快速计算法
May 9th, 2013
8 comments
原创文章，转载请注明： 转载自系统技术非业余研究
本文链接地址: log2的快速计算法
从erl_mseg.c中摘抄的：
static const int debruijn[32] = {
0, 1, 28, 2, 29, 14, 24, 3, 30, 22, 20, 15, 25, 17, 4, 8,
31, 27, 13, 23, 21, 19, 16, 7, 26, 12, 18, 6, 11, 5, 10, 9
};
#define LOG2(X) (debruijn[((Uint32)(((X) & -(X)) * 0x077CB531U)) >> 27])
供大家参考！
Post Footer automatically generated by wp-posturl plugin for wordpress.
Recent Comments