Re: ALU - Don't know where to start

Posted by Technik on Apr 01, 2013; 8:05am
URL: http://nand2tetris-questions-and-answers-forum.52.s1.nabble.com/ALU-Don-t-know-where-to-start-tp4026279p4026574.html

Hey,

Had to take a break for a while, but I'm back again. I've drawn out and coded what I think is a pretty good description of the math circuit (haven't got to the status bits).

When I try to test, it says comparison failure at line 3. Here's my output:

|        x         |        y         |zx |nx |zy |ny | f |no |       out        |
| 0000000000000000 | 1111111111111111 | 1 | 0 | 1 | 0 | 1 | 0 | 0000000000000000 |
| 0000000000000000 | 1111111111111111 | 1 | 1 | 1 | 1 | 1 | 1 | 1111111111111111 |

Which according to the alu-nostat.cmp file, should be fifteen 0s and a 1 at the end instead of sixteen 1s. Not sure I understand what's going on with that.

Mind if I PM you a picture of my sketch & the HDL I've written thus far?