32位无符号整数平方根

      1 int isqrt(unsigned x)                                                                                       
      2 {
      3     unsigned m, y, b;
      4
      5     m = 0x40000000;
      6     y = 0;
      7     while(m != 0)
      8     {
      9         b = y | m;
     10         y = y >> 1;
     11         if(x >= b)
     12         {
     13             x = x - b;
     14             y = y | m;
     15         }
     16         m = m >> 2;
     17     }
     18     return y;
     19 }