Comment by mort96
Comment by mort96 5 days ago
I don't understand what the difference is between "an ARM chip with native x86 translation" and a dual-ISA x86 and ARM chip.
And I don't understand why you'd want a dual-ISA x86 and ARM rather than just an x86 chip. You wouldn't get whatever CPU front-end simplicity advantages there are from ARM, since your front-end would get significantly more complex and consume significantly more transistors than with a normal x86 chip. And I don't think there's a market of people who want ARM for compatibility reason; any Windows software which supports ARM also supports x86.
What they could do is to release an ARM chip with a slightly extended ISA to add the select features which are difficult to emulate in software, such as loads and stores with the memory ordering guarantees x86 provides but ARM doesn't. Apple does this AFAIK, and it's one part of why Rosetta 2 is so good. But any ARM CPU maker could do this.
I think the core question is whether hardware-accelerated translation could be meaningfully faster than software like Rosetta 2/Prism while avoiding the full dual-ISA complexity you're describing. Rather than literally implementing both instruction sets, it might be more like an ARM chip with specialized translation units and the extended ISA features you mentioned (memory ordering, etc.).
Intel's unique position with x86 IP could make this feasible where others can't, but whether the engineering effort is worth it for what might be a short-term market advantage is debatable.