The Apple M1 SoC was, without a doubt, one of the most important technological innovations of the apple company. His arrival occurred in 2020, and it was confirmation of numerous rumors that Tim Cook’s men were going to abandon x86 architecture to jump to ARM architecturealthough starting from a totally own design.
With that move Apple not only has he gained control, but he has also left a significant amount of money at home and has been able to eliminate third-party dependency on hardware refresh cycles. In terms of performance, the apple company was also able to reach a good level, and showed that the Apple M1 was very competitive, especially when it comes to its performance per watt ratio.
To meet the challenges of transitioning from the x86-x64 architecture to an ARM architecture, Apple used an emulation method known as Rosetta 2and the result it has achieved has been very good, so much so that many people were pleasantly surprised by the excellent work that Apple had done with said solution.
It wasn’t clear how Apple was able to achieve such a great level of Rosetta 2 emulation, but thanks to Dougall Johnson, an Australian security researcher, we’re a little clearer. It seems that this solution has a “secret” extension that streamlines the process of saving parity and adjusting of indicators within an application. This allows for more accurate and “faster” emulation, according to Johnson, but the most interesting thing about all this is that this was included in the second processor that Intel released, the legendary 8080 from 1974.
The Intel 8080 worked with those parity settings and stores in a very specific way, and the feature was so important that It was extended until it reached the most current Intel processors. This means that the Intel Core i9-13900K has a direct correlation with the processors that were used 50 years ago.
In ARM, bits 26 and 27 of the flag register are dedicated to that process, although those two bits are only assigned to it when Rosetta 2 is in use, and this emulation layer is not activated unless it detects that a program or application designed for Intel is being used. That automatic reassignment and the support that we have explained are the key to that good performance of the Apple M1 SoC and Rosetta 2.
