Alignment Exceptions on or off by default?

I’m running the RO5 ROM dated 23-Feb-24 on a Pi4B, and on bootup, AlignEx (which is set to launch on boot) shows AE on, but a moment after the complete desktop displays, AE switches to off. My understanding is that current ROMs set AE to on by default, so I’m wondering what is switching it off on my system (and should I worry either way)?

The “CPU” configuration plugin (supplied with RISC OS Pi) also controls alignment exceptions.

If you use the Iris web browser then IIRC it turns AlighEx off to allow the browser to work properly, as it uses some “Thumb2” facilities within the WebKit part as I understand it. I have mine turned off.

I know some around here say you must have it turn on or bad things will happen.

I know some around here say you must have it turn on or bad things will happen.

I think that was mainly to catch and reject old software that relied upon the previous “rotated loads” behaviour, but the last machine to support that was the Pi 1.
Maybe it’s time to allow unaligned loads to be real unaligned loads?

Maybe it’s time to allow unaligned loads to be real unaligned loads?

If you can mark packages with that requirement (and may as well compile for ARMv7), and don’t care for RPCEmu etc.

Mmmm this sounds like a big problem. When do we know a program needs align ON or OFF? Try and error each time a program crashes?
Any guidance which program needs what? Any list/examples which one needs ON?
So !iris needs off and checks it by itself.