The power model used in M-sim is a modified version of WATTCH.
Compared to the original WATTCH implemented on Simplescalar, the M-sim version of WATTCH explicitly models the register file, Issue Queue, ROB and LSQ instead of using Reservation Station Units. The code was changed to reflect this change (this change is unsupported).
Minor changes for statistics registering were made to handle the changeover to CMP.
An offline version of WATTCH was generated for PTLSIM . This may or may not be publicly available.