Comment by pjjpo
6 hours ago
> Despite the name, register VMs also have a stack.
Out of curiosity what do you think about this - in spite of the name, stack machines also have yet another stack. Ok I don't like that wording, but locals are basically the stack frames people know of from their computer arch class I think.
It doesn't change the fact that Wasm operations have to have the execution stack as one or more of the operands. Seems like a stack machines to me too, though I don't know more details on why the specific design of Wasm would make optimizing compilers harder to write than JVM as the article suggests (I think?).
As you said, it's more like CPU stack frames. In a register VM all instructions can read and write to any position in the stack frame. In a stack VM, most instructions only read and write to the top but they are often combined with LOAD and STORE instructions, which can read and write to any position in the stack frame.