PURPOSE: To avoid a process from being reset to preceding interruption processing before next interruption processing is through, by forming a queue with a pointer set to a head entry and the pointer set to next and final entries from each entry.
CONSTITUTION: An interruption 1 occurs during an active mode of a task 1 which extracts an entry out of a queue and a task 2 adds an entry 4a to the queue. Here the task 2 adds first a pointer 1a to an area 7 for the head and final entries. Then this pointer 1a is updated by means of a comparison updating instruction and the entry 4a to be added to the pointer set to the final entry is instructed. If an interruption occurs by a task 3, the task 3 stores the pointer 1a for head and final entires updated by the task 2 into an area 8. The pointer 1a is updated again with a comparison updating instruction and an entry 5a is instructed.
OZAKI TAKASHI
NONAKA HIROSHI
