Two-State Switch and Display

[Weregoose]

You're in a loop that does one of two things: either it constantly displays 1, or it constantly displays 0. Pressing [2nd] will switch between these two events. Pressing [CLEAR] will terminate the loop. Do this in 30 bytes.*

*That is, if the program's name is TEASER (a six-letter name), then the respective byte count on the memory management screen would be 30 + 6 = 36 bytes if the program's code matches the answer in number of bytes.

[vuurrobin]

I have it currently at 35 bytes (without name) and I can take 3 bytes of if I asume A is 0 prior to running the program, and another 2 bytes if I use 2 getkeys instead of 1, but with that, pressing a key will sometimes not be notised.

[DarkerLine]

I think I got it.

[Weregoose]

That's it exactly. I can see this being a relevant optimization inside some programs – the concept is not all that uncommon.

[DarkerLine]

Did you come up with this as a response to the "why is xor useful at all" discussion on TI|BD?

[Weregoose]

I wasn't really looking for a way in which it'd be useful, but xor did come to mind as I was writing something, probably due to that conversation. Based off of that something, here is a two-item custom menu:

0:ClrHome // zero added to prevent ERR:DATA TYPE
Output(4,1,"Normal -- Expert
Repeat Ans=105
A xor 1=abs(Ans-25→A
Output(4,8,sub("<->",Ans+1,2
getKey
End
ClrHome
If A=0
Disp "Normal
If A=1
Disp "Expert

What's great about this is that the setting is "remembered" between uses of the program.

[Igrek]

I have an other version, also 30+6 bytes:

[DarkerLine]

[Weregoose]

Right, but that version's slower, and [2nd] will occasionally not work; as occasionally as it does work, [CLEAR] loses its opportunity to work, because getKey takes on the value of the most recent keypress and then discards it, causing other instances of getKey to zero out until another keypress is made.

[EDIT] – Beaten by DarkerLine.

[alexrudd]

In one of my classes this year, I actually used an extremely similar idea (using xor to flip one variable based on the status of another) It allowed a robot (circuit board with an infrared sensor, a microcontroller, and 2 motors) to avoid walls. Using xor was absolutely the smallest and fastest way of doing what needed to be done.

Of course, then I spent quite some time struggling to make it work on hardware because the microprocessor was getting a little interference from the motors which was causing the xor instruction to work one more time than necessary in a 1000Mhz loop, because my instructor insisted I put a duty cycle on the motors, and ....

[WikiGuru]

hehe, you can cut out 5 bytes if [ON] is the quit key

:While 1
:A xor getKey=21->A
:Disp A
:End