Buffering an internal signal to an output

[Jeremy Weatherford]

Since internal pins cannot be sub-bused, is there a way to send an internal signal directly to an output pin?  I ran into this with the ALU trying to set the NG output -- I had to use an intermediate internal signal for the ALU's output so I could pull off the sign bit.  Now how do I get the internal signal to the output?  I wound up using And16(a=out1, b=out1, out=out), but this seems rather ugly.

I'm running into the same thing now with implementing the CPU... would be nice to be able to "buffer" one signal directly into another one, unless I'm completely missing something -- always possible.

[Jeremy Weatherford]

Ah, and the other reason I need a buffer of some kind... can't connect an output signal to another chip's input signal.  It seems to me that in Figure 5.9, the small unlabeled circles are effectively buffers -- but the caption and text do not explain what they are or how to implement them.

[ybakos]

Sorry if I'm misunderstanding what you're trying to do, but it sounds like you can solve your problem by taking the penultimate output and wiring it to both chip out and another internal pin. You can then route the internal pin into your other chip.

[Jeremy Weatherford]

I see what you mean... I didn't realize I could connect a part's output to multiple signals, that will help.  Thanks for the quick feedback, and the fascinating book!