ASM - Pushing/Popping

Question

Why is it that when you push a value onto the stack, the ESP register is decreased (as opposed to increased) and when you pop a value, the ESP register is increased (as opposed to decreased)? This is counter intuitive to me at this point.

Answer 1

Thats because that way the stack "grows" from top to bottom, opposed to the heap, which is allocated bottom up.

On architectures with a limited address space this was a design decision, you can use them both more flexible - only the sum of both allocated memory regions must not exceed a certain limit.

Nowadays the stack and heap address space is kept in separate memory regions anyway, but they decided to keep the backwards growing stack.