ALU Test Script

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ALU Test Script


My ALU passes the test script... but I don't think that it should!

While I was working on the "no status bits" version of the ALU, as suggested by various posters to these forums, I commented out the zr and ng output pins in the chip definition. I just noticed this morning while running ALU.tst  script that my ALU only had two outputs listed in the "output" box: Out[16] and ng. I had forgotten to uncomment zr! My ALU has a zr pin, but because I'd commented out the output zr pin mine is an internal pin that doesn't connect to anything except the output of a Not - but it passes the script test just fine.

This is not a big problem, I suppose, except that, when it comes to integrating the ALU into a larger project I can imagine receiving a lot of strange errors about missing pins that might have been confusing and hard to track down.

Looking at the script file, it seems like maybe there's no way to check whether a pin is internal or external? Maybe name collisions like this can't be tested for.

- N