Patent US 3,974,480

This invention relates to a data processing system, specially for real-time applications. This system comprises a processor having a relatively small number of registers, and safeguard storages consisting each of a stack of sequentially addressable registers. When a program being performed is interrupted, all the information contents of the processor registers are transferred to at least one safeguard storage. The transferred information are subsequently extracted, upon resumption of the interrupted program, from the safeguard storage, in a sequential order reverse with respect to the order in which they had been previously transferred. This system is specially adapted for controlling industrial processes.