REGISTER/SAVING/RESTORING SYSTEM FOR SAVING AND RESTORING DATA IN A REGISTER OF A SLAVE PROCESSOR

A register saving/restoring system for use in a data processing system is constructed of a CPU and at least one slave processors. The registers of the slave processors are not saved nor restored when the CPU switches tasks, however the descriptor of the task carried out in one slave processor most recently and the descriptor of a task being executed by the CPU are compared so that the slave processor registers are saved and restored. This process is done only if the descriptors are different, in order to avoid the waste register saving/restoring processing.