Eval button unavailable

Posted by 97vyaas on Mar 08, 2020; 3:39am
URL: http://nand2tetris-questions-and-answers-forum.52.s1.nabble.com/Eval-button-unavailable-tp4034290.html

I was unable to find Xor.hdl in my 00 projects file for first assignment (as described in the video). I typed in the following code on the Xor.hdl file in 01 file under projects:

CHIP Xor {
    IN a, b;
    OUT out;

    PARTS:
    // Put your code here:
    Not (in=a, out=nota);
    Not (in=b, out=notb);
    And (a=a, b=notb, out=c);
    And (a=nota, b=b, out=d);
    Or (a=c, b=d, out=out);
}

After I changed one of the variables to 1 or 0, the eval button remains unavailable. But when I use the built-in Xor.hdl chip, it works properly. Can anyone help me with this? Thanks!