ALU idk whats wrong

Posted by Nicolas on Jun 20, 2011; 7:33pm
URL: http://nand2tetris-questions-and-answers-forum.52.s1.nabble.com/ALU-idk-whats-wrong-tp3087773.html

So I have written the following for the ALU. To me logically it seems to work fine yet it fails the comparison chart on 90% of the lines. I don't know whats wrong could someone please point me to my errors so I at least know where I am going wrong. Thanks.

Edit: Implementation removed. Hint: I did this using 1081 Nand gates, yet it can be done with less.

...
        Not16(in=,out=);
        Inc16(in=,out=);                                  //here was my problem
        Mux16(a=,b=,sel=,out=);
...