Patent ID: 6564306
Filing Date: 2003-05-13
Classification: G06F

Abstract:
A directory-based memory subsystem within a computer system that performs speculative tag updates, the directory-based memory subsystem comprising:a number of memory banks that store memory lines that include multiple words, at least one word of each memory line including a tag field that stores state information including information that identifies a memory-line owner, including one of a single-processor owner of the memory line, and multiple processors that share ownership of the memory line; a memory controller that reads memory lines from the number of memory banks and that writes memory lines to the number of memory banks; and a tag control unit that, when a memory line is read from the number of memory banks, receives the at least one tag field from the memory line, updates the at least one tag field, and speculatively writes the at least one updated tag field back to the number of memory banks, with any errors in the memory line subsequently detected, using embedded error-correcting codes, and corrected by the memory controller.