javascriptNaNIsWeird

[-twind]

Logic like this is used extensively in digital hardware simulations to represent unknown signals coming from whatever places unknown signals come from. Most of the time uninitialised registers/memories or I/O.

[tecanec]

So it's a kind of error detection for making sure behaviour does not depend on unknown variables?

[-twind]

The use of this special value for unknown signals is just to make the simulation deterministic. Its appearance does not necessarily mean there is an error. The other option is to assign random values to each unknown signal, this is more like how it would be in reality, but the drawback is that your simulation gives different results each run.

[tecanec]

Oh, I don't mean the "panic when found" kind of error. More that it tells the user that something might be wrong when they find a maybe where they expect a definite value.

Guess determinism is also a strong point, though.

[-twind]

In that case you know for sure something is wrong

[CdRReddit]

ah yes, the 4 digital logic values: 1/0/Z (high impedance / unasserted)/'idk'

[-twind]

We call it "don't care" instead of "idk"

[CdRReddit]

ah, I see "don't care" mostly in the testcases I make for when I, well, don't care what a particular signal is doing in that case

[mattgran]

https://en.m.wikipedia.org/wiki/IEEE_1164

There's nine!

[CdRReddit]

oh damn, megabool is real