INFORMATION PROCESSOR WHICH REWRITES INSTRUCTIONS IN PROGRAM TO DYNAMICALLY CHANGE PROGRAM STRUCTURE AND METHOD THEREFOR

An information processor comprises a program storage unit and a control unit, the control unit includes a procedure insertion table in which information regarding an embedding point in a program and information regarding an insertion procedure to be inserted in the embedding point are described in correlation with each other, and a program dynamically changing unit for saving an instruction at an embedding point of the program held in the program storage unit in a predetermined instruction saving region with reference to the procedure insertion table, rewriting the last instruction of an insertion procedure into a branch instruction to branch to an instruction subsequent to a saved instruction, and writing the branch instruction to branch to the insertion procedure at the embedding point, thereby, at the time of execution of the insertion procedure, executing the instruction saved in the instruction saving region immediately before executing the last branch instruction.