FEX is the shootstring, extra special discount budget (not maligning) version of Rosetta. Apple should sell Rosetta to Valve.
> Apple M1 has an undocumented extension that, when enabled, ensures instructions like ADDS, SUBS and CMP compute PF and AF and store them as bits 26 and 27 of NZCV respectively, providing accurate emulation with no performance penalty.
macOS 26 is the last OS with an Intel build. Presumably this means that in all likelihood, M6 chips will remove this functionality.
They might even decide that they will be moving that functionality to software and decide to also leverage FEX.
I think that Apple’s overall mentality has traditionally been that they provide enough time for developers to transition applications but that they are not interested in maintaining support for unmaintained apps. That seems to be a very clear pattern of behavior.
That's crazy. Modifying an already-working CPU design to remove hardware features, and modifying Rosetta to implement that capability in software instead, or wholly replacing Rosetta with FEX, would all require investing more resources and effort than continuing to ship what's already done and working.
> I think that Apple’s overall mentality has traditionally been that they provide enough time for developers to transition applications but that they are not interested in maintaining support for unmaintained apps. That seems to be a very clear pattern of behavior.
Fair enough, but we don't actually have to make projections based on past patterns of behavior when Apple has explicitly shared their plans. They do plan to maintain support for unmaintained games.
I think the only reasonable way to interpret what Apple has said about their plans for Rosetta is to assume they're not likely to muck about with the low-level details of how they handle running x86 machine code, but they are likely to start dropping some x86 libraries from the OS, breaking applications that depend on them. We can reasonably expect that they're retain all the pieces necessary for running x86 Windows software (especially games) under Wine. (Keep in mind that Apple's approach is to not mix x86 and Arm code in the same process; they didn't do anything like Microsoft's Arm64EC.)
In reality, the costs of design changes and validation and updating software to not rely on a newly-deprecated hardware feature can easily outweigh the potential per-chip cost savings of eliminating an instruction or two from a CPU core.
Intel and AMD have to maintain compatibility in a much different way. They don’t control what is done on the OS, they don’t control what is done with the physical product sold in stores. They have gigantic customers like Dell and HP and Microsoft that make specific technical demands out of their architecture.
Apple controls the whole stack. They decide exactly what features are in software and are in hardware. There are zero Apple machines in data centers running BigCorp’s legacy CashCow software. There are zero laptop or desktop OEMs that use Apple’s chips besides Apple. Apple won’t piss off their core consumer or creative professional customers by changing some technical behind-the-scenes feature.
I think Apple would gladly cut a very small and specific architecture feature from their chips if they feel it’s obsolete, better accomplished in software or not at all.
And this isn’t just for cost savings, it could be for performance and/or battery life optimization, or to make room for something else in the package.
First, these features are a big draw for developers (a key macOS audience).
Second, the ability to run Windows games is not getting less valuable.
I believe that running Windows games is something that Apple does not care about at all. Their efforts to create the game porting tool kit are 100% about getting more Windows games ported to the macOS App Store.
You do want FEAT_AFP though, so you do want ARMv8.6+.
AF indeed is basically unused. The problem for both is that you need them for accurate emulation "just in case".
The JavaScript instruction is cooler though.
https://developer.arm.com/documentation/dui0801/g/A64-Floati...
The other stuff is all present in ARMv8.5 I think.
QEMU exists. I doubt they want the bad press of suing an Open Source project everyone is using.
They seemed quite happy to destroy their eco system if they won.
https://www.rcrwireless.com/20251001/business/qualcomm-arm-2
Isn't Rosetta kinda bad though? And won't get much better because it's not open source?
As for not improving, it is likely that Apple no longer feels the need to invest in Rosetta improvements now that Apple silicon is so dominant and software support is already very strong, but nothing is stopping them from investing in it if they need it for example for gaming
Why would a company on its way to the moon, entrust such an important project as translation layer between two major architectures to a single rinky-dinky corp that got rich selling common electronics marketed as luxury fluff, that's on the decline and has head so far stuck up its butt that it thinks it can do whatever it wants, instead of just write it themselves with support of the global developer community?
Apple could never do games because there are no luxury games. That's completely out of their zone of comprehensibility.
Apple products have pretty good build quality and perf per watt that more than justifies the premium. AS far as I can tell, the only payer in the market thats even trying to compete with apple on quality in the laptop space is framework. But Framework can't make their own chips.
The games industry as a whole is in potentially terminal decline, have you seen all of the redundancies lately?
But smaller games and indie studios are thriving. We got lots of very interesting indie games this year.
Gabe Ownership/co-founder:
- Valve - Yacht Companies - Starfish Neuroscience (Neuralink) - Submarine Companies