Continuous signature monitoring: efficient concurrent-detection of processor control errors

Concurrent detection of processor control errors using signatured programs is discussed. The approach, called continuous signature monitoring (CSM), makes significant advances beyond the existing signature-monitoring techniques. For typical programs, CSM decreased average error-detection latency by as much as eight times, down to 1.2 to 1.6 program memory cycles. Memory overhead for storing signatures reaches a theoretical minimum, lowered as much as four times, dozen to 3-7%. The CSM monitor is less complex by more than half, and processor-performance loss is reduced as much as 10 times down to 0.6-1.5%. CSM increases coverage of control-flow errors and detects certain types of errors not detected by the existing techniques, including a stuck program counter