Unsigned division in Java

[iago]

After much pondering, I figured it out.  It's a little messy, but isn't all that bad:

Code Select Expand

       public static int Divide(int a, int b)
       {
               long c = a;
               long d = b;

               c = c & 0xFFFFFFFFl;
               d = d & 0xFFFFFFFFl;

               long lResult = (long)c / (long)d;                              

               return (int)(lResult & 0xFFFFFFFFl);
       }

Which can be shortened to this:

Code Select Expand

       public static int Divide(int a, int b)
       {                                                                      
               // Basically, we treat them as longs then mask out the sign-    
               // extension.                                                  
               return (int)(((long) a & 0xFFFFFFFFl) / ((long) b & 0xFFFFFFFFl));                                                                              
       }


[edit] Fixed a line break that vi added
[edit2] Fixed a small glitch with the second program

[Banana fanna fo fanna]

+a million

[iago]

I'm wondering what kp will say, mostly

[Kp]

I'm wondering what kp will say, mostly

If you wanted unsigned division, why are you using Java?

[iago]

I'm wondering what kp will say, mostly

If you wanted unsigned division, why are you using Java?

I did it in a fairly clean way, though!  

[Adron]

I noted before that you can do unsigned multiply and divide by using signed numbers with > twice the bits.

[iago]

I don't remember you noting that, but it's fairly logical if you think about it.

[Adron]

Yes. What you have to be careful about is that you need 64-bit signed numbers to handle 16-bit unsigned, unless there's some trick I missed.