WRITE BARRIER APPARATUS AND METHOD FOR TRAPPING GARBAGE COLLECTION PAGE BOUNDARY CROSSING POINTER STORES

摘要

Architectural support is provided for trapping of garbage collection page boundary crossing pointer stores. Identification of pointer stores as boundary crossing is performed by a store barrier responsive to a garbage collection page mask that is programmably encoded to define a garbage collection page size. The write barrier and garbage collection page mask provide a programmably-flexible definition of garbage collection page size and therefore of boundary crossing pointer stores to be trapped, affording a garbage collector implementer with support for a wide variety of generational garbage collection methods, including train algorithm type methods to managing mature portions of a generationally collected memory space. Pointer specific store instruction replacement allows implementations that provide an exact barrier not only to pointer stores, but more particularly to pointer stores crossing programmably defined garbage collection page boundaries.