What is Stack Pointer?

if the triggering is taken place at the level of the clk signal which we have giving as the input to processor.

i.e if the instruction is exicuted or if the states of the registers or flags get effected at the level of the clk then it is called as the level triggering.

Stack pointer is a special purpose 16-bit register in the Microprocessor, which holds the address of the top of the stack.