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For CPU developers it's permissionless. To develop a new Arm chip you need to negotiate a license up front from that company. To develop a new x86 chip, well,

by rwmj 4y ago

For CPU developers it's permissionless. To develop a new Arm chip you need to negotiate a license up front from that company. To develop a new x86 chip, well, forget about that. Intel won't license x86 for any amount of money. For RISC-V, download a BSD-licensed core from github, or grab the BSD-licensed specs and write your own. No need to ask anyone's permission, and no fees to pay.

iso8859-1 4y ago
But since AMD owns amd64, can't you get a license from them?
- yjftsjthsd-h 4y ago
  Somehow I doubt that they're much more friendly about it. At a technical level, though it's an interesting question; I'm actually pretty curious to know whether you could make a processor that's pure amd64 without the legacy 32-bit mode... I suspect it would be a fair bit of work from the software side to support that, but it's probably possible. But I'm no ISA designer:) Edit: Or is 32-bit x86 so old that you could "just" clone it because all the patents have expired?
  - ZiiS 4y ago
    amd64 uses Intel IP; even if you removed all legacy modes.
- Steltek 4y ago
  Historically, Intel and AMD had an exclusive IP sharing agreement with each other. That would not extend to other parties.
  - wolpoli 4y ago
    So it means the entity wanting to develop an amd64 processor will need licenses from both Intel and AMD. I don't see how this could practically happen through.
- Pet_Ant 4y ago
  I don't know how far you'd get with an amd64 core that didn't support x86. I mean you couldn't run Windows on it. You probably could run Surface as it's almost certainly legacy-free as it can run on ARM.
bluGill 4y ago
If you are a CPU developer either you need to use x86-64 for compatibility, or you can use whatever you feel like it. Risc-v is still good though because the fact that others are using it mean you don't have to build a compiler for your new one. (eventually you may want to work on the optimizer)

by rwmj 4y ago

iso8859-1 4y ago

But since AMD owns amd64, can't you get a license from them?

yjftsjthsd-h 4y ago
Somehow I doubt that they're much more friendly about it. At a technical level, though it's an interesting question; I'm actually pretty curious to know whether you could make a processor that's pure amd64 without the legacy 32-bit mode... I suspect it would be a fair bit of work from the software side to support that, but it's probably possible. But I'm no ISA designer:) Edit: Or is 32-bit x86 so old that you could "just" clone it because all the patents have expired?
- ZiiS 4y ago
  amd64 uses Intel IP; even if you removed all legacy modes.
Steltek 4y ago
Historically, Intel and AMD had an exclusive IP sharing agreement with each other. That would not extend to other parties.
- wolpoli 4y ago
  So it means the entity wanting to develop an amd64 processor will need licenses from both Intel and AMD. I don't see how this could practically happen through.
Pet_Ant 4y ago
I don't know how far you'd get with an amd64 core that didn't support x86. I mean you couldn't run Windows on it. You probably could run Surface as it's almost certainly legacy-free as it can run on ARM.

bluGill 4y ago

If you are a CPU developer either you need to use x86-64 for compatibility, or you can use whatever you feel like it. Risc-v is still good though because the fact that others are using it mean you don't have to build a compiler for your new one. (eventually you may want to work on the optimizer)