Using introspective software-based testing for post-silicon debug and repair

As silicon process technology scales deeper into the nanometer regime, hardware defects are becoming more common, to the point of threatening yield rates and product lifetimes. Introspective software mechanisms hold great promise to address these reliability challenges with both low cost and high coverage. To address these challenges, we have developed a novel instruction set enhancement, called Access-Control Extensions (ACE), that can access and control a microprocessor´s internal state. Using ACE technology, special firmware can periodically probe the microprocessor during execution to locate run-time faults, repair design errors (even those discovered in the field), and streamline manufacturing tests.