diff options
| -rw-r--r-- | src/cpu/o3/lsq_unit.hh | 54 |
1 files changed, 35 insertions, 19 deletions
diff --git a/src/cpu/o3/lsq_unit.hh b/src/cpu/o3/lsq_unit.hh index cd512ced7..7c3e0e026 100644 --- a/src/cpu/o3/lsq_unit.hh +++ b/src/cpu/o3/lsq_unit.hh @@ -1,5 +1,5 @@ /* - * Copyright (c) 2012-2014,2017-2018 ARM Limited + * Copyright (c) 2012-2014,2017-2018,2020 ARM Limited * All rights reserved * * The license below extends only to copyright in the software and shall @@ -209,6 +209,14 @@ class LSQUnit }; using LQEntry = LSQEntry; + /** Coverage of one address range with another */ + enum class AddrRangeCoverage + { + PartialAddrRangeCoverage, /* Two ranges partly overlap */ + FullAddrRangeCoverage, /* One range fully covers another */ + NoAddrRangeCoverage /* Two ranges are disjoint */ + }; + public: using LoadQueue = CircularQueue<LQEntry>; using StoreQueue = CircularQueue<SQEntry>; @@ -707,6 +715,8 @@ LSQUnit<Impl>::read(LSQRequest *req, int load_idx) bool lower_load_has_store_part = req_s < st_e; bool upper_load_has_store_part = req_e > st_s; + auto coverage = AddrRangeCoverage::NoAddrRangeCoverage; + // If the store entry is not atomic (atomic does not have valid // data), the store has all of the data needed, and // the load is not LLSC, then @@ -715,6 +725,29 @@ LSQUnit<Impl>::read(LSQRequest *req, int load_idx) store_has_lower_limit && store_has_upper_limit && !req->mainRequest()->isLLSC()) { + coverage = AddrRangeCoverage::FullAddrRangeCoverage; + } else if ( + // This is the partial store-load forwarding case where a store + // has only part of the load's data and the load isn't LLSC + (!req->mainRequest()->isLLSC() && + ((store_has_lower_limit && lower_load_has_store_part) || + (store_has_upper_limit && upper_load_has_store_part) || + (lower_load_has_store_part && upper_load_has_store_part))) || + // The load is LLSC, and the store has all or part of the + // load's data + (req->mainRequest()->isLLSC() && + ((store_has_lower_limit || upper_load_has_store_part) && + (store_has_upper_limit || lower_load_has_store_part))) || + // The store entry is atomic and has all or part of the load's + // data + (store_it->instruction()->isAtomic() && + ((store_has_lower_limit || upper_load_has_store_part) && + (store_has_upper_limit || lower_load_has_store_part)))) { + + coverage = AddrRangeCoverage::PartialAddrRangeCoverage; + } + + if (coverage == AddrRangeCoverage::FullAddrRangeCoverage) { // Get shift amount for offset into the store's data. int shift_amt = req->mainRequest()->getVaddr() - store_it->instruction()->effAddr; @@ -761,24 +794,7 @@ LSQUnit<Impl>::read(LSQRequest *req, int load_idx) ++lsqForwLoads; return NoFault; - } else if ( - // This is the partial store-load forwarding case where a store - // has only part of the load's data and the load isn't LLSC - (!req->mainRequest()->isLLSC() && - ((store_has_lower_limit && lower_load_has_store_part) || - (store_has_upper_limit && upper_load_has_store_part) || - (lower_load_has_store_part && upper_load_has_store_part))) || - // The load is LLSC, and the store has all or part of the - // load's data - (req->mainRequest()->isLLSC() && - ((store_has_lower_limit || upper_load_has_store_part) && - (store_has_upper_limit || lower_load_has_store_part))) || - // The store entry is atomic and has all or part of the load's - // data - (store_it->instruction()->isAtomic() && - ((store_has_lower_limit || upper_load_has_store_part) && - (store_has_upper_limit || lower_load_has_store_part)))) { - + } else if (coverage == AddrRangeCoverage::PartialAddrRangeCoverage) { // If it's already been written back, then don't worry about // stalling on it. if (store_it->completed()) { |