Patent ID: 6922744

Claim:
A circuit apparatus associated with a mid-level cache for handling side-door communal software lock (CSWL) inquiries in a multiple instruction-processor computer system said computer system having other mid-level caches with similar circuit apparatae associated with said other mid-level caches, said circuit apparatus comprising: a. inquiry generator for generating said CSWL inquiries, said CSWL inquiries being signals containing either CSWL requests or status reports regarding locked status of a CSWL, and for providing such CSWL requests and status reports to a side door of one of said other mid-level caches, b. receiving circuit for receiving said CSWL requests and status reports from said similar circuit apparatae associated with said other mid-level caches, c. Interpreter for reading the signals in a received CSWL inquiry to determine if it relates to a CSWL mapped to said associated mid-level cache and what each particular lock request function requires for said received CSWL inquiry, d. CSWL cache memory within said associated mid-level cache for storing CSWLs to which said associated mid-level cache is mapped, and means for determining if a CSWL which is subject to said received CSWL inquiry is present within said CSWL cache memory, e. comparator circuit for determining a current value of a requested CSWL within said mid-level cache's memory, f. CSWL inquiry processor for processing said received CSWL inquiry and for generating a response to said received CSWL inquiry, g. A circuit for responding to a requesting local processor with a status received from a status report.