Q. What is Stack Addressing?

In this addressing technique operand is implied as top of stack. It isn't explicit however implied. It employs a CPU Register known as Stack Pointer (SP). SP points to the top of stack which means to the memory location where last value was pushed. A stack offers a sort-of indirect addressing and indexed addressing. This isn't a very common addressing technique. The operand is found on top of a stack. In a number of machines top two elements of stack and top of stack pointer is kept in CPU registers whereas the rest of elements may exist in memory. Figure below displays the stack addressing schemes.

Figure: Stack Addressing