Combining Hardware- and Software-Based Self-Repair Methods for Statically Scheduled Data Paths

This paper describes hardware- and software-based self-repair methods and how to combine them in order to obtain hybrid methods. All presented methods are able to handle multiple permanent faults in processors with a statically scheduled data path, e.g. a VLIW processor. They are based on adapting the executed program in the field to the current fault situation. The first method is a simple hardware-based technique. It binds dynamically operations to other execution units. A recently published first software-based method is briefly described, and a new second software-based method is introduced to overcome some weaknesses of the first one. Two hybrid methods are obtained by combining each software-based method with the hardware-based method. A detailed analysis of the advantages and disadvantages of each method is given. This includes a reliability analysis, the hardware overhead, the repair time, and the effect of multiple faults on the runtime of an executed application.