Apple Silicon M1 Emulating x86 Is Still Faster Than Every Other Mac

Re:Apple Silicon M1 Emulating x86 Is Still Faster Than Every... by klelatti on Sunday November 15, 2020 @08:11PM (#25106818)

I think that the legal requirements will depend on the precise instructions - eg your linked article mentions SIMD. Certainly the basic x86-64 extension to x86 originated at AMD who (due to cross license deals) licenses them to Intel but things like AVX are Intel. I suspect that code emitted by Xcode omits these newer instructions.

Bear in mind too that a lot of the x86 patents will have expired by now.

[ Parent | on HN ]

Re:Apple Silicon M1 Emulating x86 Is Still Faster Than Every... by saagarjha on Sunday November 15, 2020 @08:14PM (#25106836)

Xcode will emit those if you ask for it, and macOS ships some binaries that use those instructions. However, Rosetta doesn't do AVX.

[ Parent | on HN ]

Re:Apple Silicon M1 Emulating x86 Is Still Faster Than Every... by klelatti on Sunday November 15, 2020 @08:15PM (#25106846)

Interesting. How does Rosetta deal with apps with AVX then?

[ Parent | on HN ]

Re:Apple Silicon M1 Emulating x86 Is Still Faster Than Every... by wmf on Sunday November 15, 2020 @08:24PM (#25106916)

Such apps will use CPUID to detect that AVX is not implemented and they won't use any AVX instructions.

[ Parent | on HN ]

Re:Apple Silicon M1 Emulating x86 Is Still Faster Than Every... by klelatti on Sunday November 15, 2020 @09:15PM (#25107215)

Of course. So Rosetta will simply follow the non AVX path.

[ Parent | on HN ]