I'm not a lawyer but I would assume its copyright. Kind of like API in software. In software somehow this does not apply most of the time. But it seems in hardware this is very real. But I would appreciate a lawyer jumping in.
I know for example that Berkley when thinking pre-RISC-V that they had a deal with Intel about using x86-64 for research. But they were not able to share the designs.
I don't know why there aren't independent X86-64 manufacturers. Patents on the extensions maybe? But as I understand copyright, APIs can't be copyrighted so it's not that.
The original amd64 came out in 2003. Any patents on the original instruction set have long expired, and even more so for 32-bit x86.
Its not about patents. Believe what you want but there is a reason nobody else is doing x86 or ARM chips unless they are allowed by the owner.
You're probably right. It would be helpful to say what the reason is, if it's not patents.
I'm not a lawyer but I would assume its copyright. Kind of like API in software. In software somehow this does not apply most of the time. But it seems in hardware this is very real. But I would appreciate a lawyer jumping in.
I know for example that Berkley when thinking pre-RISC-V that they had a deal with Intel about using x86-64 for research. But they were not able to share the designs.
I don't know why there aren't independent X86-64 manufacturers. Patents on the extensions maybe? But as I understand copyright, APIs can't be copyrighted so it's not that.
The original ARM 32 stuff is clearly out of patents and is not being copied. And it doesn't require new extensions to be commercially viable.