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Would be too difficult to implement. x86 is a very big instruction that is impossible to implement with an hardware: both Intel and AMD processors in fact run i

Would be too difficult to implement. x86 is a very big instruction that is impossible to implement with an hardware: both Intel and AMD processors in fact run inside a virtual machine that translates x86 instructions in an internal RISC instruction set that is manageable by the real CPU architecture. If Apple decided to move away from x86 and go to ARM to have their processor, and we are talking about one of the biggest companies, I don't think any community project will ever succeed in doing another x86 compatible CPU. On the other side RISCV instruction set is far simpler, being a RISC instruction set it decides to not have advanced optimizations in the processor (even better, none at all) and leave the optimization work to the compiler, that not only simplifies the processor, but also reduces the surface of attack of the processor (Meltown, Spectre, and all these attacks are just impossible on RISCV!). Of course that has a performance penalty, but since you simplify the processor you can just put more core in the saved space right?

userbinator 5y ago
I'm not sure if you're being satirical, but open source x86 cores do exist --- they're around a 486 in terms of compatibility. Look up ao486 for example. What I'm referring to is the expiration of patents from the P6 era, which would mean all the uop-based stuff is now free to implement. What a lot of the RISC hype doesn't understand is the huge value in backwards compatibility --- you can have your "100% free" world but it'll forever remain niche. We need to accommodate the proprietary world if we want any chance of freedom winning; and not try to divide the world of computing.
- coldtea 5y ago
  >I'm not sure if you're being satirical, but open source x86 cores do exist --- they're around a 486 in terms of compatibility. And they will stay at that level, is the parent's point, which is 25+ years before today and thus affordable to clone and fabricate. It's not about 486 or for that matter 8086 beinh difficult...
als0 5y ago
RISC-V is not immune to Spectre and Meltdown because these are implementation vulnerabilities. Any CPU implementation that uses out-of-order and speculative execution has to constantly worry about introducing these holes.
- userbinator 5y ago
  And on the other side, neither were early Atoms; but everyone knows what their performance is like.

userbinator 5y ago

I'm not sure if you're being satirical, but open source x86 cores do exist --- they're around a 486 in terms of compatibility. Look up ao486 for example. What I'm referring to is the expiration of patents from the P6 era, which would mean all the uop-based stuff is now free to implement. What a lot of the RISC hype doesn't understand is the huge value in backwards compatibility --- you can have your "100% free" world but it'll forever remain niche. We need to accommodate the proprietary world if we want any chance of freedom winning; and not try to divide the world of computing.

coldtea 5y ago
>I'm not sure if you're being satirical, but open source x86 cores do exist --- they're around a 486 in terms of compatibility. And they will stay at that level, is the parent's point, which is 25+ years before today and thus affordable to clone and fabricate. It's not about 486 or for that matter 8086 beinh difficult...

als0 5y ago

RISC-V is not immune to Spectre and Meltdown because these are implementation vulnerabilities. Any CPU implementation that uses out-of-order and speculative execution has to constantly worry about introducing these holes.

userbinator 5y ago
And on the other side, neither were early Atoms; but everyone knows what their performance is like.