The x86-64 extension was made by AMD, though, not by Intel. So if at all the license would have to be obtained from AMD... Interestingly, https://en.wikipedia.

The x86-64 extension was made by AMD, though, not by Intel. So if at all the license would have to be obtained from AMD... Interestingly, https://en.wikipedia.org/wiki/X86-64 https://en.wikipedia.org/wiki/X86-64 says this: > x86-64/AMD64 was solely developed by AMD. AMD holds patents on techniques used in AMD64; those patents must be licensed from AMD in order to implement AMD64