Processor and program execution method capable of efficient program execution

A program execution method for executing a program in a processor, the processor including a plurality of register groups and sequentially executing a plurality of programs using a plurality of register value groups stored in a memory that correspond one-to-one with the programs, comprising:

• a select/switch step of selecting one of the plurality of register groups as an execution target register group on which a program execution is based, and switching the selection target every time a first predetermined period elapses;
• a restoring step of restoring, every time the switching is performed, one of the register value groups into one of the register groups that is not selected as the execution target register group;
• a saving step of saving, prior to the restoring, register values in the register group targeted for restoring, by overwriting a register value group in the memory that corresponds to the register values;
• and
• a program execution step of executing, every time the switching is performed, a program corresponding to a register value group in the execution target register group.

A processor for sequentially executing a plurality of programs using a plurality of register value groups that correspond one-to-one with the programs, comprising:

• a plurality of register groups for storing the register value groups;
• a select/switch unit operable to select one of the plurality of register groups as an execution target register group on which a program execution is based, and to switch the selection target every time a predetermined period elapses;
• and
• a program execution unit operable to execute, every time the switching is performed, a program corresponding to a register value group in the execution target register group.