Multiprogram control information processing system with process roll-in from main memory

A multiprogram control information processing system with process roll-in from a main memory to hardware of a central processing unit of said multiprogram control information processing system, comprising:

• a plurality of sets of visible registers, each of said plurality of sets of visible registers corresponding to each of a plurality of processes stored in corresponding saving areas of said main memory, having a distinct entry number and being configured by various registers for collectively representing current processing status of the corresponding process;
• entry number generating means having a memory for storing identification codes of said plurality of processes and the entry numbers of said plurality of sets of visible registers in one-to-one correspondence, said entry number generating means being adapted to receive a given identification code of a process to be rolled in from said main memory, to output a given entry number corresponding to the given identification code, to output a hit signal representing a coincidence, and to output a mishit signal if the given identification code is not present in said memory;
• selector means for selecting one of said plurality of sets of visible registers in correspondence with the given entry number output from said entry number generating means to connect the one of said plurality of sets of visible registers selected by said selecting means to an arithmetic unit;
• and
• roll-in control means for controlling to immediately initiate execution of a new process corresponding to said set of visible registers selected by said selector means in response to the hit signal, and to output an entry number selected from said memory according to an arbitrary selection scheme to said selector means and to roll-in the necessary information from said corresponding saving area in said main memory to a set of visible registers having the entry number selected according to the arbitrary selection scheme in response to the mishit signal.