What type of machine language do PCs generally run on

Question

I've recently begun researching what it would take to program a JIT compiler. I've been studying on machine language, but I haven't been able to find what type of machine languages most standard PCs run on. I found this PDF which seems to explain a type of ML, but it says it's MIPS, which, after looking it up, seems to be some kind of old, videogame console/router machine language. So, my question is,

What machine language do most modern personal computers (i.e. laptops, desktops) run on?

Or, is it indeterminable? Are there many machine languages? Or maybe I'm wrong, and MIPS is standard?

Answer 1

The machine language used by a given processor is a function of its instruction-set architecture ("ISA").

Most desktop and laptop computers today running Microsoft Windows use "64-bit" processors implementing the "x86-64" ISA, such as those in Intel's "Core i5" and "Core i7" processor families. Commonly referred to as "x64", this is the 64-bit extension (created by AMD) for the original "IA-32" ISA (created by Intel).

Both "IA-32" and "x64" are examples of Complex Instruction Set Computing ("CISC") architectures. On the other hand, MIPS is an example of the much simpler Reduced Instruction Set Computing ("RISC") style of architectures.

When talking about JIT compilers, it is important to distinguish between the ISA of the virtual machine running the byte-code and the ISA of the underlying physical processor. Most virtual machines are based upon RISC architectures, because of their relative simplicity. However, most likely this VM-plus-JIT-compiler will be physically running on an x64-compatible CISC processor.