[Ericson2314]

Sure I'm not disagreeing with the legal history, but on what merits is one patentable, and the other either fair use to reimplement or not even copywritable!!

I could understand Intel having a CPU patent for specific CPUs, but an specific ISA?!

A really interesting test case would be to implement an isomorphic encoding to x86 with same instruction widths and what-not such that it's trivial to convert binaries from one to the other, and modify compilers (especially the JIT ones).

[wtallis]

We shouldn't necessarily assume that the x86 patent war chests are legally sound. Rather, Intel and AMD have a mutually assured destruction cross-licensing arrangement and they need each other to stay viable to fend off antitrust regulators. But they would prefer not risking an unfavorable precedent by actually wielding their patents in court, so their deterrent operates more on the promise of protracted and expensive litigation, rather than on the promise that Intel would actually win against an upstart CPU vendor.