Stack-based model

A stack is indeed a fundamental data structure that forms the operational basis of stack-based virtual machines. This kind of VM relies on the stack for various computations. To illustrate this, let's consider a basic addition operation:

In a stack-based VM, operands are implicitly processed via the stack pointer. There's no need to specify the operand address directly; calling the stack pointer fetches the next operand. This happens through stack operations like PUSH (adding data onto the stack) and POP (removing the topmost data from the stack).

For example, if we want to perform an operation such as A + B = C, the stack-based VM would go through these steps:

LOAD A: This pushes the local variable A onto the stack.

LOAD B: This pushes the local variable B onto the stack.

ADD: This operation pops the two values from the top of the stack, adds them together, and then pushes the result back onto the stack.

STORE C: This pops the top value from the stack and stores the result in the local variable C.

In this way, all arithmetic and logical operations are performed by first popping operands from the stack, executing the operation, and then pushing the result back onto the stack. While the stack-based model is simple and allows for easy operation execution, it can often result in longer code lengths and slower execution speeds compared to register-based VMs.