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Undocumented arm64 ISA extension present on the Apple M1

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Re: Undocumented arm64 ISA extension present on the Apple M1

#71

Post by monocasa »

rgovostes wrote: post #59
gcblkjaidfj wrote: post #39

Earlier quoted context omitted.

Apple must support base LLVM functionality because it is the core of their extend-embrace-extinguish strategy. This says nothing that they will extend that offer to their undocumented secret sauce, as you imply.

Don't be absurd. LLVM was a research project until Apple hired Chris Lattner and poured money into it to make a viable alternative to GCC. They've been among the project's top contributors (financially and in terms of code) for 15 years. That's quite the long con. Apple creates plenty of proprietary technologies but I can't think of a time they've been credibly accused of crushing an open technology that already exis…

They did that, in part, because they were subject of one of the first GPL enforcement actions, originally being unwilling to open source their objc GCC frontend. They being Nextstep at the time, but there's not a huge distinction these days.

Their investment in LLVM is very much an attempt to keep reproprietization on the table.

Re: Undocumented arm64 ISA extension present on the Apple M1

#72

Post by segfaultbuserr »

EricE wrote: post #65
mhh__ wrote: post #7

Earlier quoted context omitted.

In the bigger picture Apple aren't really documenting anything for their new toys, which is not the end of the world but is a huge step back for openness. There is - as far as I can see - no long-form documentation for M1 other than patents. I already refuse to own apple products so I don't really have any skin in the game, but consider that if microsoft were like this the blind eye would not be turned - buy our new…

Or maybe different people have different needs and don’t care if every device is “open”. The vast majority of people are not enamored with technology for technologies sake. These are tools. Does the tool do what I want with the least amount of friction? That’s what they care about. Also how does Apples stance on one product in any way change the device you are using to post in any way? Are Apple thugs coming to your…

> If you don’t like their computing model then don’t use it. Railing that they aren’t supporting your vision lockstep is pretty freaking arrogant.

Alternatively, try to learn more about it by reverse engineering, which is what this article is all about.

Re: Undocumented arm64 ISA extension present on the Apple M1

#73

Post by retaeelppa »

vmception wrote: post #69
mhh__ wrote: post #7

Earlier quoted context omitted.

In the bigger picture Apple aren't really documenting anything for their new toys, which is not the end of the world but is a huge step back for openness. There is - as far as I can see - no long-form documentation for M1 other than patents. I already refuse to own apple products so I don't really have any skin in the game, but consider that if microsoft were like this the blind eye would not be turned - buy our new…

My life is so much better being in the Apple ecosystem. Some of it was unintentional, but now its iPhone, Macbook Pro, Apple Watch, Airpods Pro, and IOT devices that use Homekit. I have an iPad but I use it the least. Pre-Intel I used to make fun of "Apple fanboys". But aside from the niche and incompatibilities of the PowerPC architecture back then, that turned out to be a lot of other immaturities I had and was rai…

Once you're done frolicking in the garden, tech outside can use some help.

ICS and CUPS are a testament to how strange Apple is as a company. See also: libimobiledevice.org

I hold that they're hands-down the worst company at marketing.

Re: Undocumented arm64 ISA extension present on the Apple M1

#74

Post by realusername »

rwmj wrote: post #46
ac29 wrote: post #38

Earlier quoted context omitted.

> How are they expecting that people will use these new instructions? Only through Apple-supplied closed source compilers and libraries? This sounds right. Forcing people to use Apple supplied and supported libraries allows Apple to make major changes in hardware without breaking compatibility (there are always edge cases, though).

If the compiler generates these instructions, won't old binaries break if Apple later make changes in the hardware? (For shared libraries it would be "ok" because the old binary could use the new library, as long as Apple didn't also break the ABI).

Apple does not care that much about backward compatibility so having two incompatible binaries with the same architecture wouldn't shock me that much.

Re: Undocumented arm64 ISA extension present on the Apple M1

#75

Post by joseph_grobbles »

notretarded wrote: post #70
joseph_grobbles wrote: post #68

Earlier quoted context omitted.

Apple added special AMX instructions specifically for matrix operations. They added them back with the A13, and then improved them for the M1. These are primarily focused on machine learning training where you do backpropagation through huge matrix operations. They provide a very wide coverage library set that works on all supported platforms optimally. You interact with AMX through those libraries, and direct usage…

>These are primarily focused on machine learning training where you do backpropagation through huge matrix operations How is this different from normal matrix operations?

Scale, and only scale. As with most extensions, there's negative value if you're doing a small number of calcs, but it pays off in larger needs like ML training.

We've been calculating matrixes for time eternal, but AMX has just recently become a thing. Intel just introduced their own AMX instructions.

Re: Undocumented arm64 ISA extension present on the Apple M1

#76

Post by simion314 »

user-the-name wrote: post #48
tenebrisalietum wrote: post #17

Earlier quoted context omitted.

Apple can make tools that use the undocumented ISA, which they don't have to release to the public, potentially using it to develop applications with performance advantages that no one other than Apple can attain. It's similar to how Microsoft doesn't make all APIs on Windows public and uses non-public ones for various reasons--except this is in hardware. It's possible the undocumented ISA is used to speed up x86 emu…

> Apple can make tools that use the undocumented ISA, which they don't have to release to the public, potentially using it to develop applications with performance advantages that no one other than Apple can attain. Why would they? They sell hardware, not really software.

>They sell hardware, not really software.

But they make more money from the Apple Store and the other services and they are always giving advantages to their own stuff on iOS like using private APIs or bypassing security rules .

Re: Undocumented arm64 ISA extension present on the Apple M1

#77

Post by dayjobpork »

rgovostes wrote: post #61
mhh__ wrote: post #51

Earlier quoted context omitted.

My point about the docs isn't the day-to-day stuff, but the things that cannot be machine generated - to write a good compiler you need to know the details of how the CPU is put together underneath. Intel will give you 800 pages on how to optimize for their current ISA (AMD will give you 45, but still)

As I understand it, Intel will also sell you a compiler that can optimize better than GCC because they know internal microarchitecture details. To me, that seems like a more clear-cut by-design conflict of interest between chip designer and user than these undocumented instructions.

You think it is bad that a company provides good documentation on how their product works and how to use it?

Re: Undocumented arm64 ISA extension present on the Apple M1

#78

Post by vmception »

retaeelppa wrote: post #73
vmception wrote: post #69

Earlier quoted context omitted.

My life is so much better being in the Apple ecosystem. Some of it was unintentional, but now its iPhone, Macbook Pro, Apple Watch, Airpods Pro, and IOT devices that use Homekit. I have an iPad but I use it the least. Pre-Intel I used to make fun of "Apple fanboys". But aside from the niche and incompatibilities of the PowerPC architecture back then, that turned out to be a lot of other immaturities I had and was rai…

Once you're done frolicking in the garden, tech outside can use some help. ICS and CUPS are a testament to how strange Apple is as a company. See also: libimobiledevice.org I hold that they're hands-down the worst company at marketing.

Speaking of the garden, what garden!?

iOS devices have had a file system users can at least save and retrieve from for years now.

The mobile app landscape has changed from the gold rush early last decade, and I rarely install anybody's. I empathize with the developers still trying to make it there, but its not a user's problem.

The protocols that Apple chooses to promulgate work really well.

Flagship games work really well.

The garden has gotten really big, I can't see the walls anymore but little bad gets in.

Computers do what I want them to, here. They don't do what I want them to do outside of here. For context, I jump into a Windows instance, or routinely put compute instances in the cloud.

Re: Undocumented arm64 ISA extension present on the Apple M1

#79

Post by supermatt »

rgovostes wrote: post #25
mhh__ wrote: post #7

Earlier quoted context omitted.

In the bigger picture Apple aren't really documenting anything for their new toys, which is not the end of the world but is a huge step back for openness. There is - as far as I can see - no long-form documentation for M1 other than patents. I already refuse to own apple products so I don't really have any skin in the game, but consider that if microsoft were like this the blind eye would not be turned - buy our new…

On the other hand, Apple released their 64-bit ARM backend for LLVM[1] in 2014. They announced their intention do so almost immediately after the first ARM64 phone, but the process took several months because it had to be merged with a duplicate backend developed by others. I think it is likely that support for these instructions will be upstreamed to LLVM, and the teams involved in this monumental transition (which…

I just started getting into macOS and iOS development and the documentation is HORRENDOUS.

Even the classroom educational material Apple put out is incomplete, outdated, and often completely wrong!

Additionally, It seems to be impossible to compile anything in Xcode other than a hello-world without gettting undocumented warnings and (non fatal) errors logged, which, if you can find a matching thread on their forums, usually results in a “just mark it down as log noise”.

Has it always been this bad?

Re: Undocumented arm64 ISA extension present on the Apple M1

#80

Post by mhh__ »

EricE wrote: post #65
mhh__ wrote: post #7

Earlier quoted context omitted.

In the bigger picture Apple aren't really documenting anything for their new toys, which is not the end of the world but is a huge step back for openness. There is - as far as I can see - no long-form documentation for M1 other than patents. I already refuse to own apple products so I don't really have any skin in the game, but consider that if microsoft were like this the blind eye would not be turned - buy our new…

Or maybe different people have different needs and don’t care if every device is “open”. The vast majority of people are not enamored with technology for technologies sake. These are tools. Does the tool do what I want with the least amount of friction? That’s what they care about. Also how does Apples stance on one product in any way change the device you are using to post in any way? Are Apple thugs coming to your…

> Or maybe different people have different needs and don’t care if every device is “open”.

Just because Apple are boiling the frog doesn't make it a good thing.

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