Nand gate counter

[rrauenza]

I was curious how many nand gates were in each of my chips, so I wrote a a script that parses the HDL flies and recursively counts the gates.

https://github.com/rrauenza/nand2tetris-nand-counter

It depends on the python lark-parser module.

Have fun!

[WBahn]

Thanks, some may find it quite useful.

Does it handle the implied parallelism of the basic gates, or do people need to avoid using it in order for the counter script to work properly?

[rrauenza]

I've only tested it up to project 2.

I don't know what you mean by the implied parallelism handling -- it just looks at each chip and recursively looks up its parts until it reaches a nand gate, and adds 1 to the nand count when it finds each nand gate.

I ignore the [x..y] ranges as they don't matter -- the count just goes over the parts.

For example, Not16 would have a parts list of 16 Nots, which each has a parts list of 1 Nand.  So Not16 is 16.

Here are my counts:


$ ./counter.py  *.hdl                                                          
And: 2                                                                          
Mux16: 64                                                                      
And16: 32                                                                      
Or8Way: 21                                                                      
Mux4Way16: 192                                                                  
Mux8Way16: 448                                                                  
DMux8Way: 35                                                                    
Nand: 1                                                                        
DMux4Way: 15                                                                    
Not: 1                                                                          
Not16: 16                                                                      
HalfAdder: 7                                                                    
Add16: 262                                                                      
Or16: 48                                                                        
FullAdder: 17                                                                  
Xor: 5                                                                          
Or: 3                                                                          
ALU: 772                                                                        
Inc16: 262                                                                      
Mux: 4                                                                          
DMux: 5  

I was thinking of trying to do a more efficient Inc166 per the lecture and so was curious if I could do it with fewer gates -- but obviously needed a tool to count them first!  

[rrauenza]

And now my question is answered ...

My Inc16 is 112 nands with half adders and 263 nands with full adder (Add16).

I'm also really interested in the implementation mentioned in the lecture (my post in the Chap 2 forum):

http://nand2tetris-questions-and-answers-forum.32033.n3.nabble.com/Incrementer-optimization-mentioned-in-lecture-td4033241.html