SECURING METHOD OF VARIABLE AREA IN RECURSIVE PROGRAM

PURPOSE:To improve the processing efficiency, by knowing unequivocally the variable area of a desired block level on a basis of the lowest block level in a program, the block level after start, and contents of a stack pointer before starting. CONSTITUTION:The block of block level 1 is started, and contents (SP) of a stack pointer 40 indicating the start position of the variable area and a size (SIZE) of the variable area are added for the purpose of securing a variable area 511, and the addition result is defined as new contents SP1 of the stack pointer 40. When the block of the next block level 2 is started after the process of block level 1 is executed, the operation of SP+SIZE is executed again to secure a variable area. Contents of the stack pointer 40 are written in a stack area 30 at every update time to form position information. The variable area of an optional level is detected by referring to the stack area 30 even during starting block level N.