Manually Computing XOR (Exclusive OR) using AND / OR operators

[kevin]

 Manually Computing XOR (Exclusive OR) using AND / OR operators


   Ever wonder how to create your own XOR function using only AND and OR ?

PlayBASIC Code: [Select]

   //   Run in DEBUG MODE to see output

   For lp =0 to 1000

      A=(RND($ffff) << 16) or RND($ffff)
      B=(RND($ffff) << 16) or RND($ffff)

      Result1= A Xor B
      Result2= Xor2(A,B)
      s$ ="Test #"+STr$(lp)+"  "
      s$+=hex$(Result1) +  "   "+ hex$(Result2)

      if Result1!=Result2
            s$+="Failed"
      endif
      print s$
      #print s$   


      Sync
   next

   Sync
   waitkey
   
   
   
   
Function Xor2(A,B)

         // Mask input bits together to find the common bits in both
         Mask = A and B

         // Invert Mask (remember 2's complement :) )
         InvertedMASK = -1 - MASK

         // Clean bits out that appear in both, since we should only
         // return set bits when a bit is 1/0 or 0/1 
         A= A And InvertedMask
         B= B And InvertedMask

         // Or them together
         Result = A or B
EndFunction Result