Register allocation for hybrid register architecture in nonvolatile processors

Nonvolatile processors (NVP) have been an emerging topic in recent years due to its zero standby power, data retention and instant-on features. The conventional full replacement architecture in NVP has drawbacks of large area overhead and high backup energy. This paper provides a partial replacement based hybrid register architecture to significantly abate above problems. However, the hybrid register architecture can induce potential critical data loss and backup errors. In this paper, we propose a critical-data overflow aware register allocation (CORA). Different from other register allocation methods, CORA efficiently reduces the possibility of critical data spilling and backup errors. The experiment results show that CORA reduces the critical data overflow rate by up to 52%. The hybrid register architecture reduces the chip area by 45.1% and backup energy by 82.8% when using CORA.