摘要 |
A method is provided for executing a subroutine in a computer which includes a memory and a stack. The memory has a plurality of sequentially ordered memory address locations referenced by respective address codes. The subroutine is stored in a preselected range of memory locations. The method includes storing a signature word on the stack, the signature word corresponding to an entry address code in memory for the subroutine; storing a return address on the stack, the return address code corresponding to a memory location where control is to be passed after execution of the subroutine; passing control to the subroutine entry address; executing the subroutine; comparing the signature word stored on the stack with the subroutine entry address code; passing control to the return address if the compared values are equal; and executing a software interrupt if the compared values are not equal. |