I don't think that Apple will completely get away from x86 for a long time. Attempting to emulate the x86 on an Arm would be terribly slow.
I do however, think that they will eventually include both arm and x86 processors in the Macbook Air. That way, backwards compatibility is preserved and low power apps can run on the arm. In the current Macbook Pros they have dynamic switching of GPUs, there's no reason they couldn't use the arm as a coprocessor or even run the full OS.
Here a few technical points:
* LLVM - You can compile once for both both architecture and then the JIT will take over compiling for the specific architecture (Take a look at llvm for the OpenGL pipe line in OSX)
Full screen app- When an app is full screen (if it's a low power app) then the x86 could sleep and the arm could switch to running the app.
App nap - If all x86 apps are a sleep, switch over the running the arm processor exclusively
*Saving State - It's possible to save the state of apps in OSX, a similar mechanism could be used to seamlessly migrated between processors.
This is pure speculation, but it is feasible. There would be many technical challenges that Apple would have to solve but the a capable. The advantage Apple has is that they have absolute control over both platforms.
I do however, think that they will eventually include both arm and x86 processors in the Macbook Air. That way, backwards compatibility is preserved and low power apps can run on the arm. In the current Macbook Pros they have dynamic switching of GPUs, there's no reason they couldn't use the arm as a coprocessor or even run the full OS.
Here a few technical points:
* LLVM - You can compile once for both both architecture and then the JIT will take over compiling for the specific architecture (Take a look at llvm for the OpenGL pipe line in OSX)
Full screen app- When an app is full screen (if it's a low power app) then the x86 could sleep and the arm could switch to running the app.
App nap - If all x86 apps are a sleep, switch over the running the arm processor exclusively
*Saving State - It's possible to save the state of apps in OSX, a similar mechanism could be used to seamlessly migrated between processors.
This is pure speculation, but it is feasible. There would be many technical challenges that Apple would have to solve but the a capable. The advantage Apple has is that they have absolute control over both platforms.