高效率开平方算法

 1 UINT sqrt(long m)
 2 {
 3 
 4     BYTE i,j;
 5     UINT z,temp0,temp1;
 6     long x,y;
 7     x = 1;
 8 
 9     for(j =0;j<16;j++)
10     {
11         x <<= 2;
12         if(m<x)
13             break;
14     }
15     x = y =1;
16     x <<=2*j;
17     y = x<<1;
18 
19     z = 0;
20     temp0 = 0;
21     for(i=0;i<=j;i++)
22     {
23         z <<= 1;
24         temp0 <<= 2;
25         if(m&x)
26             temp0++;
27         if(m&y)
28             temp0 += 0x02;
29         m <<= 2;
30         temp1  = z;
31         temp1 = (temp1<<1) + 1;
32         if(temp1<=temp0)
33         {
34             temp0 -=temp1; 
35             z++;
36         }
37     }
38 
39     return z;    
40 
41 }