MEMORY POOL CONTROL CIRCUIT

PROBLEM TO BE SOLVED: To confirm easily whether or not a memory area may be released in a system wherein a common memory is shared. SOLUTION: A common memory 19 is divided into memory spaces having a predetermined number of fields and a CAM 11 stores a pointer which manages free areas of the common memory and flags indicating whether fields are in use, field by field. An area securing module 15 secures a memory space as a secured memory space according to access to the common memory and rewrites the pointer in the CAM. An in-area access module 14 sets a flag in the CAM according to the use state of the field in the secured memory space. When a retrieval control machine 16 performs retrieval from the CAM to confirm that all the fields of the secure memory space are not used, an area releasing module releases the secured memory space.