Re: ALU - Don't know where to start

Posted by cadet1620 on Feb 13, 2013; 2:32pm
URL: http://nand2tetris-questions-and-answers-forum.52.s1.nabble.com/ALU-Don-t-know-where-to-start-tp4026279p4026282.html

Look at the text in Figure 2.5. There function description is lots of "ifs". The easiest way to make choices in hardware is with Multiplexors -- generate both signals you might need and select the one you do need.

Be sure to read Appendix A.5.3; you'll want to use sub-busing to make the status bits. Also read how "true" and "false" constants work.

This post has test files that only test the arithmetic part of the ALU which makes it easier to build.  Once the arithmetic works you can concentrate on the status flags.

--Mark