[dannyw]

No; it’s not explained very well but the M1 chip features hardware support for TSO which Rosetta2 uses.

It’s really ‘Apple Silicon’ and not just ARM.

[dirtypersian]

> It's really 'Apple Silicon' and not just ARM.

Yeah, I think that's key to understanding this. They are supporting a version of ARM ISA running that maintains TSO even though official ARM doesn't need to support TSO. I guess this is all to get better emulation performance and avoid those extra synchronization instructions that would have to be added by Rosetta if the silicon did not have TSO support.