Research ways to make execution more complex

[llysdal]

Here's my ideas:

• Only propagate to next gate if the output has changed. (This would screw up gates that can change output on the same input, as the input would never reach them)
• If the above is implemented, a gate that could force execution somewhere. This would however decrease understanding greatly I think.
• Branching gates. If this, then propagate value to this gate, else propagate to this gate. Complex constructs with many gates like ALUs wouldn't have to execute every gate anymore, just the section relevant.
• Lazily calculated gates. Maybe an "if" gate could just check if the relevant input has arrived? There's no reason to wait for the input that isn't going to be used.
• Steal some features from E2, like "changed" and "last". "Last" has already been implemented, but in 3 different ways - none behaving exactly like the E2 one. Changed could be made using a Delta gate, but that only works for numbers. Maybe a "changed" gate that could work in conjunction with the first point? As in, it could halt execution if the value hasn't changed.

I'm rambling - there's a lot of options though, with some of them breaking current chips. There's some non-destructive approaches such as adding more gates, but that throws us into a corner, as we can't remove those gates in the future.