Re: ZR and NG using 16wayOR gate?

Posted by WBahn on Jul 11, 2020; 4:28am
URL: http://nand2tetris-questions-and-answers-forum.52.s1.nabble.com/ZR-and-NG-using-16wayOR-gate-tp4034824p4034838.html

guynextdoor wrote

We are getting the 0 output as a single bit anyway. or as I understand the ZR output as to be 16 bit bus output?

What is leading you to that understanding?

Look at the spec for the ALU (Figure 2.5).

The ALU has three outputs: out[16], zr, and ng.

The 'out' signal is a 16-bit signal. But the 'zr' and 'ng' outputs are single-bit outputs. The 'zr' output is a 1 (i.e., true) if the value of the 'out' signal is exactly 0, otherwise it is a 0 (i.e., false).