Inventors: Matsumoto, Kazuya;
Assignee: NEC Corporation (Tokyo, JP)
Primary Examiner: Chan; Eddie P.
Assistant Examiner: Bragdon; Reginald G.
Attorney, Agent or Firm: Sughrue, Mion, Zinn, Macpeak & Seas, PLLC
A lock control for a data processing system providing lock control for each data processing unit in the data processing system. The lock control is carried out based on a state of a lock variable, by a lock request control unit of a cache unit connected to the dam processing unit. On receipt of a lock request or unlock request, the lock request control unit indexes a lock address register holding an address of the lock variable and refers to a state of a lock stored in a corresponding lock status register. Various kinds of states are defined as a state of a lock variable to indicate that each lock request control unit is in a lock or unlock state. A symbol ULE indicates the state that no acquisition of a lock in all lock request control units is confirmed. Thus, an acquisition of a lock corresponding to a particular lock request control unit can be done with high speed, without confirming states of lock request control units other than the particular lock request control unit. |
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