1. A real-time embedded simple monitor method for performing a scheduling of a plurality of interrupt service routines based on a semaphore structure and an interrupt-control-block sequence, the real-time embedded simple monitor method comprising: interrupt-service-routine starting including saving, when an interrupt occurs, a value of a program counter, a stack pointer that is a value of a stack register, and a context stored in a stack area at a time of the interrupt occurrence, in a context saving area of an interrupt control block corresponding to an interrupt service routine that is interrupted; and setting the interrupt control block corresponding to the occurred interrupt to an execution-waiting state; scheduling including selecting an interrupt control block having a highest priority from among the interrupt control blocks that are set to the execution-waiting state; saving a value of a program counter, a stack pointer, and a context stored in a context saving area of the selected interrupt control block, in the stack area; and executing an interrupt service routine selected by an interrupt return command; and interrupt-service-routine exiting including setting, when exiting a process of the interrupt service routine executed at the scheduling, an interrupt control block corresponding to the exiting interrupt service routine to an interrupt-waiting state, wherein the semaphore structure is applied to an embedded software configured with the interrupt service routines including a steady-state, is associated with a plurality of semaphores used for the interrupt service routines, and holds information on a usage state of the semaphores, and in the interrupt-control-block sequence, plural interrupt control blocks holding information on a state of each of the interrupt service routines corresponding to interrupt levels of the interrupt service routines are connected in order of a priority of the interrupt level.