Abstract: A method and system for optimizing shift operations by reducing the computational overhead and the number of full scan path shifts associated with accessing and modifying data on a rotating scan path image are disclosed. The system further simplifies the construction of a scan path image by inserting a programmable number of leading and trailing bits around a selected string of data bits. The system manipulates and constructs a scan path image without having to shift or prepare the entire scan path image in memory. Specifically, the system comprises a master controller having a lead bypass module, a trail bypass module, a first shift module, a second shift module, a select module and a shift control module. Collectively, these modules comprise the necessary hardware for executing a plurality of shift optimization functions which include lead and trail bypass insertion, non-destructive read, field isolation, field insertion, bit order reversion, bit rotation and simultaneous read and write operation.