Yousuke Nakamura Kei Hiraki Heterogeneous Functional Units for High Speed Fault-Tolerant Execution Stage. 260-263 2007 PRDC http://doi.ieeecomputersociety.org/10.1109/PRDC.2007.45 conf/prdc/2007 db/conf/prdc/prdc2007.html#NakamuraH07