1. A non-copy shared stack and register file device comprising: a register set having a plurality of registers for executing register-based instructions; a data stack having a plurality of stack items and a stack pointer for executing stack-based instructions; a selector connected to each stack item of the data stack and at least one register of the register set for being switched to make at least one stack item communicate with the at least one register; and a control circuit for controlling the selector and updating the stack pointer to switch the selector to make the stack item pointed by the stack pointer communicate with the at least one register.