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It is quite astonishing how seamless Apple has managed to make the Intel to ARM transition, there are some seriously smart minds behind Rosetta. I honestly don't think I had a single software issue during the transition!
Earlier quoted context omitted.
> I hope Rosetta is here to stay and continues developement. It almost certainly is not. Odds are Apple will eventually remove Rosetta II, as they did Rosetta back in the days, once they consider the need for that bridge to be over (Rosetta was added in 2006 in 10.4, and removed in 2011 from 10.7). > And I hope what is learned from it can be used to make a RISC-V version of it. translating native ARM to RISC-V should…
>That's not going to happen unless Apple decides to switch from ARM to RISC-V, and... why would they? They've got 15 years experience and essentially full control on ARM. Two points here. • First off, Apple developers are not binded to Apple. The knkwledge gained can be used elsewhere. See Rivos and Nuvia for example. • Second, Apple reportedly has already ported many of it's secondary cores to RISC-V. It's not unrea…
Apple's historically been pretty good at making this stuff. Their first 68k -> PPC emulator (Davidian's) was so good that for some things the PPC Mac was the fastest 68k mac you could buy. The next-gen DR emulator (and SpeedDoubler etc) made things even faster. I suspect the ppc->x86 stuff was slower because x86 just doesn't have the registers. There's only so much you can do.
Not arguing the facts here, but I'm curious—are these successes related? And if so, how has Apple done that?
I would imagine that very few of the engineers who programmed Apple's 68k emulator are still working at Apple today. So, why is Apple still so good at this? Strong internal documentation? Conducive management practices? Or were they just lucky both times?
It is quite astonishing how seamless Apple has managed to make the Intel to ARM transition, there are some seriously smart minds behind Rosetta. I honestly don't think I had a single software issue during the transition!
It isn't their first rodeo: 68k->PPC->x86_64->ARM.
It is quite astonishing how seamless Apple has managed to make the Intel to ARM transition, there are some seriously smart minds behind Rosetta. I honestly don't think I had a single software issue during the transition!
I finally started seriously using a M1 work laptop yesterday, and I'm impressed. More than twice as fast on a compute-intensive job as my personal 2015 MBP, with a binary compiled for x86 and with hand-coded SIMD instructions.
This is a great writeup. What a clever design! I remember Apple had a totally different but equally clever solution back in the days of the 68K-to-PowerPC migration. The 68K had 16-bit instruction words, usually with some 16-bit arguments. The emulator’s core loop would read the next instruction and branch directly into a big block of 64K x 8 bytes of PPC code. So each 68K instruction got 2 dedicated PPC instructions…
That’s really interesting. You might enjoy reading about the VM embedded into the Busicom calculator that used the Intel 4004 [1] They squeezed a virtual machine with 88 instructions into less than 1k of memory! [1] https://thechipletter.substack.com/p/bytecode-and-the-busico...
I hope Rosetta is here to stay and continues developement. And I hope what is learned from it can be used to make a RISC-V version of it. translating native ARM to RISC-V should be much easier than x86 to ARM as I understand it, so one could conceivably do x86 -> ARM -> RISC-V.
> I hope Rosetta is here to stay and continues developement. It almost certainly is not. Odds are Apple will eventually remove Rosetta II, as they did Rosetta back in the days, once they consider the need for that bridge to be over (Rosetta was added in 2006 in 10.4, and removed in 2011 from 10.7). > And I hope what is learned from it can be used to make a RISC-V version of it. translating native ARM to RISC-V should…
15? More than a quarter century. They were one of the original investors in ARM and have produced plenty of arm devices since then beyond the newton and the ipod.
I’d bet they use a bunch of risc v internally too if they just need a little cpu to manage something locally on some device and just want to avoid paying a tiny fee to ARM or just want some experience with it.
But RISC V as the main CPU? Yes, that’s a long way away, if ever. But apple is good at the long game. I wouldn’t be surprised to hear that Apple has iOS running on RISC V, but even something like the lightning-to-HDMI adapter runs IOS on ARM.
I hope Rosetta is here to stay and continues developement. And I hope what is learned from it can be used to make a RISC-V version of it. translating native ARM to RISC-V should be much easier than x86 to ARM as I understand it, so one could conceivably do x86 -> ARM -> RISC-V.
> I hope Rosetta is here to stay and continues developement. It almost certainly is not. Odds are Apple will eventually remove Rosetta II, as they did Rosetta back in the days, once they consider the need for that bridge to be over (Rosetta was added in 2006 in 10.4, and removed in 2011 from 10.7). > And I hope what is learned from it can be used to make a RISC-V version of it. translating native ARM to RISC-V should…
Do they? ARM made it very clear that they consider all ARM cores their own[1]
[1]: https://www.theregister.com/2022/11/07/opinion_qualcomm_vs_a...
Apple's historically been pretty good at making this stuff. Their first 68k -> PPC emulator (Davidian's) was so good that for some things the PPC Mac was the fastest 68k mac you could buy. The next-gen DR emulator (and SpeedDoubler etc) made things even faster. I suspect the ppc->x86 stuff was slower because x86 just doesn't have the registers. There's only so much you can do.
My understanding is that part of the reason the G4/5 was sort of able to keep up with x86 at the time was due to the heavy use of SIMD in some apps. And I doubt that Rosetta would have been able to translate that stuff into SSE (or whatever the x86 version of SIMD was at the time) on the fly.