I was under the distinct impression that the x86 instruction set is CISC, but modern x86 processort architecture is RISC inside, for some value of "modern" (Pentium Pro and later?).
Good observation. At one time, a long time ago, The things was about how much complexity was in the instruction set.
Here is a rather old example.
Into the time machine.... swap HL [SP] Which might be 'exchange current value of the HL pair with the current value on the stack, do do not move the pointer. That would involve a number of clock cycles, but in CISC it is a single instruction. In RISC a sequence would be needed to to the same thing. The argument is that the amount of time it takes would be about the same.
Now back to the future...Modern CPUs have been simplified internally. Some instructions are now executed using a sequence of ordinary orations instead of having super logic that implements the whole thing in hardware.
So yea, modern Intel CPUs are really RISC with a CISC wrapper. The OS and other tools see it as a CISC, but on the inside is has RISC.
Is that clear? The reasoning is that we now want to have multi-cores CPUs.So to keep them in sync they have to work as RISC to avoid the latency issues when you try and get CISC chips to work in parallel.
ARM chips are RISC. To get them to handle a CISC super structure, they need some more logic to translate the CISC codes into simple sequences. This might be what Microsoft wants to do. Rather that a emulator in software only, MS would offer a new kind of ARM design of their own that can do some of the translation. If so, then it will be a kind of
hybrid micro code and software marriage. You would have to buy a smartphone that has the new MS ARM chip and also license the MS emulator.
Put another way: It is not just a software emulation. You have to use a new ARM chip that will be an intercultural thing from Microsoft. Wait for details later.
