PURPOSE: To execute retrial extending over plural instructions, by saving the contents when reaing out from a program visible register.

CONSTITUTION: An information processor provides a main storage device 1 of large capacity for storing an instruction and an operand data, a buffer storage device 2 of a store-in buffer system, of a high speed and comparatively small capacity, an instruction controller 3 for decoding the instruction and executing an advance control of the instruction, an execution controller 4 for executing the instruction, a saving and recovery controller 5, and a saving device 6 for saving a normal state in the course of executing the instruction. After a check point has been set, when reading out the contents of registers 41W44, the content which have been read out only once are saved in the saving device 6, and when an abnormal state has been detected, the saved contents are reset to the registers 41W44.