Stacks are highly flexible in the ARM architecture, since the implementation is completely left to the software.
Stack Instructions. The
ARM instruction set does not contain any stack specific
pop. The instruction set also does not
enforce in anyway the use of a stack. Push and pop operations are
performed by memory access instructions, with auto-increment
Stack Pointer. The stack pointer is a register that points to the top of the stack. In the ARM processor, there are no dedicated stack pointer registers, and any one of the general purpose registers can be used as the stack pointer.
Stack Types. Since it is left to the software to implement a stack, different implemenation choices result different types of stacks. There are two types of stack depending on how the stack grows.
There are two types of stack depending on what the stack pointer points to.
Four different stacks are possible - full-ascending, full-descending, empty-ascending, empty-descending. All 4 can be implemented using the register load store instructions.