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Comment by wireprotocol | Hacker News Reader

Dumb question: is an ISA really proprietary? Like I can't make an ARM emulator without violating some IP law? Or just an ARM physical chip?

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Yes, the architecture is proprietary, and anyone who uses it needs a proprietary license, what sometimes involve flat payments or royalties. Check this link:

https://en.wikipedia.org/wiki/Arm_Holdings#Licensees

yes - ARM ISA is copyrighted. To implement it, you need an ISA license. ARM typically makes this license cost almost the same as the license for an already implemented core, which is why most vendors drag-and-drop ARM cores into their designs

But does this cover software emulation?

QEMU exists so I guess they're OK with software emulation but Arm seems to go on the attack at the slightest whiff of an unlicensed hardware implementation.

Are they really OK with it or are they just legally powerless to stop it? That is the question.

It may not be in their interest to stop it, as those are generally used for testing and building software to target ARM, which helps with their potential market share.

Similarly, MS offers free VMs to developers for Windows so that you can build and test against Windows without cost.

Do you have a link to those VMs?

https://developer.microsoft.com/en-us/windows/downloads/virt...

That's very cool. Thank you!

Qemu is used to by software developers to build better software/infrastructure/tooling for the chips that arm gets royalties from. It would be stupid for them to put up a roadblock here.

That's grey area.

Intel has publicly asserted that their patents apply to emulation, but is hasn't hit the courts AFAIK.

https://arstechnica.com/information-technology/2017/06/intel...

Their implementation is copyrighted. What prevents royalty-free clones is patents. MIPS was similar with certain key patents preventing clones until their recent pivot. You can clone legacy ARM architectures that aren't patent encumbered.

I think most posters in this thread are forgetting this point. RISV-V will have a key advantage because not only will it be free, but you’ll have access to high quality free implementations you can redistribute and remix without copyright issues.

People seem to forget that manufacturing and distribution of hardware is the expensive bit. "You" is never going to be an ordinary member of the public.

Making ones own small batch riscv run is in the the price range of a good used Nissan Leaf to a new 3 Series. That is for delivered silicon.

Fpga implementations start at $5.

Individuals “waste” both of those amounts of money all the time.

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