that wish to simultaneously interpret the same binary encoding.
* There is nothing in the MISA specification which permits
*future* versions (bug-fixes) of the RISC-V ISA to be "switched in".
-
+
Overall, whilst the MISA concept is a step in the right direction it's
a hundred percent unsuitable for solving the problem.
by comparison).
Also pointed out was that in certain cases pipeline stalls could be introduced
-during the switching phase, if needed.
+during the switching phase, if needed, just as they may be needed for
+correct implementation of (mandatory) support for MISA.
**This is the only one of the proposals that meet the full requirements**
> Yes. Well, it should be blocked via legal means. Incompatibility is
> a disaster for an architecture.
->
+>
> The viability of PowerPC was badly damaged when SPE was
> introduced. This was a vector instruction set that was incompatible
> with the AltiVec instruction set. Software vendors had to choose,
> Both MMX and SSE remain today, in all shipping processors. With very
> few exceptions, Intel does not ship chips with missing functionality.
> There is a unified software ecosystem.
->
+>
> This goes beyond the instruction set. MMU functionality also matters.
> You can add stuff, but then it must be implemented in every future CPU.
> You can not take stuff away without harming the architecture.