Alu arithmetic not adding up

Posted by ikanhear on May 28, 2013; 8:12pm
URL: http://nand2tetris-questions-and-answers-forum.52.s1.nabble.com/Alu-arithmetic-not-adding-up-tp4026871.html

i do not understand how the alu line x-y works.

example, x=5, y=3

5=0101
3=0011

negate x = 1010
1010 = -6

-6+3=-3
-3 flipped=3

5-3 dosent=3

surely a arithmatic negation should be used instead of an boolean one to make this work?

someone please point out what iam missing :(

thankyou in advance.