diff options
author | Kevin Lim <ktlim@umich.edu> | 2006-06-04 16:07:54 -0400 |
---|---|---|
committer | Kevin Lim <ktlim@umich.edu> | 2006-06-04 16:07:54 -0400 |
commit | 984c2a4ff677803ff7687a178f1dceb1f0204c30 (patch) | |
tree | 10dc244225a4e29a65a94cc83305a2d18d150526 /src/cpu/o3/tournament_pred.hh | |
parent | 3156f601db2728d329d9eff272bfa324ebdb2a0c (diff) | |
parent | 8671d927d862cdbdf851e74cd07d131679faa7ed (diff) | |
download | gem5-984c2a4ff677803ff7687a178f1dceb1f0204c30.tar.xz |
Merge ktlim@zamp:/z/ktlim2/clean/m5-o3
into zamp.eecs.umich.edu:/z/ktlim2/clean/newmem-merge
src/cpu/checker/o3_cpu_builder.cc:
src/cpu/o3/alpha_cpu.hh:
src/cpu/o3/alpha_cpu_impl.hh:
src/cpu/o3/alpha_dyn_inst_impl.hh:
src/cpu/o3/bpred_unit.cc:
src/cpu/o3/commit.hh:
src/cpu/o3/fetch_impl.hh:
src/cpu/o3/lsq_unit.hh:
src/cpu/o3/lsq_unit_impl.hh:
src/cpu/o3/thread_state.hh:
Hand merge.
--HG--
rename : cpu/activity.cc => src/cpu/activity.cc
rename : cpu/activity.hh => src/cpu/activity.hh
rename : cpu/base_dyn_inst.cc => src/cpu/base_dyn_inst.cc
rename : cpu/checker/cpu.hh => src/cpu/checker/cpu.hh
rename : cpu/checker/cpu_builder.cc => src/cpu/checker/cpu_builder.cc
rename : cpu/checker/exec_context.hh => src/cpu/checker/exec_context.hh
rename : cpu/checker/o3_cpu_builder.cc => src/cpu/checker/o3_cpu_builder.cc
rename : cpu/o3/2bit_local_pred.cc => src/cpu/o3/2bit_local_pred.cc
rename : cpu/o3/2bit_local_pred.hh => src/cpu/o3/2bit_local_pred.hh
rename : cpu/o3/alpha_cpu.hh => src/cpu/o3/alpha_cpu.hh
rename : cpu/o3/alpha_cpu_builder.cc => src/cpu/o3/alpha_cpu_builder.cc
rename : cpu/o3/alpha_cpu_impl.hh => src/cpu/o3/alpha_cpu_impl.hh
rename : cpu/o3/alpha_dyn_inst.hh => src/cpu/o3/alpha_dyn_inst.hh
rename : cpu/o3/alpha_dyn_inst_impl.hh => src/cpu/o3/alpha_dyn_inst_impl.hh
rename : cpu/o3/alpha_params.hh => src/cpu/o3/alpha_params.hh
rename : cpu/o3/bpred_unit.cc => src/cpu/o3/bpred_unit.cc
rename : cpu/o3/bpred_unit.hh => src/cpu/o3/bpred_unit.hh
rename : cpu/o3/bpred_unit_impl.hh => src/cpu/o3/bpred_unit_impl.hh
rename : cpu/o3/comm.hh => src/cpu/o3/comm.hh
rename : cpu/o3/commit.hh => src/cpu/o3/commit.hh
rename : cpu/o3/commit_impl.hh => src/cpu/o3/commit_impl.hh
rename : cpu/o3/cpu.hh => src/cpu/o3/cpu.hh
rename : cpu/o3/cpu_policy.hh => src/cpu/o3/cpu_policy.hh
rename : cpu/o3/decode.hh => src/cpu/o3/decode.hh
rename : cpu/o3/decode_impl.hh => src/cpu/o3/decode_impl.hh
rename : cpu/o3/dep_graph.hh => src/cpu/o3/dep_graph.hh
rename : cpu/o3/fetch.hh => src/cpu/o3/fetch.hh
rename : cpu/o3/fetch_impl.hh => src/cpu/o3/fetch_impl.hh
rename : cpu/o3/fu_pool.cc => src/cpu/o3/fu_pool.cc
rename : cpu/o3/fu_pool.hh => src/cpu/o3/fu_pool.hh
rename : cpu/o3/iew.hh => src/cpu/o3/iew.hh
rename : cpu/o3/iew_impl.hh => src/cpu/o3/iew_impl.hh
rename : cpu/o3/inst_queue.hh => src/cpu/o3/inst_queue.hh
rename : cpu/o3/inst_queue_impl.hh => src/cpu/o3/inst_queue_impl.hh
rename : cpu/o3/lsq.hh => src/cpu/o3/lsq.hh
rename : cpu/o3/lsq_unit.hh => src/cpu/o3/lsq_unit.hh
rename : cpu/o3/lsq_unit_impl.hh => src/cpu/o3/lsq_unit_impl.hh
rename : cpu/o3/mem_dep_unit.hh => src/cpu/o3/mem_dep_unit.hh
rename : cpu/o3/mem_dep_unit_impl.hh => src/cpu/o3/mem_dep_unit_impl.hh
rename : cpu/o3/rename.hh => src/cpu/o3/rename.hh
rename : cpu/o3/rename_impl.hh => src/cpu/o3/rename_impl.hh
rename : cpu/o3/rename_map.hh => src/cpu/o3/rename_map.hh
rename : cpu/o3/rob.hh => src/cpu/o3/rob.hh
rename : cpu/o3/store_set.cc => src/cpu/o3/store_set.cc
rename : cpu/o3/store_set.hh => src/cpu/o3/store_set.hh
rename : cpu/o3/thread_state.hh => src/cpu/o3/thread_state.hh
rename : cpu/o3/tournament_pred.cc => src/cpu/o3/tournament_pred.cc
rename : cpu/o3/tournament_pred.hh => src/cpu/o3/tournament_pred.hh
rename : cpu/ozone/cpu_builder.cc => src/cpu/ozone/cpu_builder.cc
rename : cpu/ozone/ozone_impl.hh => src/cpu/ozone/ozone_impl.hh
rename : cpu/ozone/simple_impl.hh => src/cpu/ozone/simple_impl.hh
rename : cpu/ozone/simple_params.hh => src/cpu/ozone/simple_params.hh
rename : python/m5/objects/AlphaFullCPU.py => src/python/m5/objects/AlphaFullCPU.py
rename : python/m5/objects/OzoneCPU.py => src/python/m5/objects/OzoneCPU.py
extra : convert_revision : b7be30474dd03dd3970e737a9d0489aeb2ead84f
Diffstat (limited to 'src/cpu/o3/tournament_pred.hh')
-rw-r--r-- | src/cpu/o3/tournament_pred.hh | 90 |
1 files changed, 81 insertions, 9 deletions
diff --git a/src/cpu/o3/tournament_pred.hh b/src/cpu/o3/tournament_pred.hh index e16600090..92402adc6 100644 --- a/src/cpu/o3/tournament_pred.hh +++ b/src/cpu/o3/tournament_pred.hh @@ -1,5 +1,5 @@ /* - * Copyright (c) 2004-2005 The Regents of The University of Michigan + * Copyright (c) 2004-2006 The Regents of The University of Michigan * All rights reserved. * * Redistribution and use in source and binary forms, with or without @@ -36,6 +36,15 @@ #include "cpu/o3/sat_counter.hh" #include <vector> +/** + * Implements a tournament branch predictor, hopefully identical to the one + * used in the 21264. It has a local predictor, which uses a local history + * table to index into a table of counters, and a global predictor, which + * uses a global history to index into a table of counters. A choice + * predictor chooses between the two. Only the global history register + * is speculatively updated, the rest are updated upon branches committing + * or misspeculating. + */ class TournamentBP { public: @@ -55,30 +64,95 @@ class TournamentBP /** * Looks up the given address in the branch predictor and returns - * a true/false value as to whether it is taken. + * a true/false value as to whether it is taken. Also creates a + * BPHistory object to store any state it will need on squash/update. * @param branch_addr The address of the branch to look up. + * @param bp_history Pointer that will be set to the BPHistory object. * @return Whether or not the branch is taken. */ - bool lookup(Addr &branch_addr); + bool lookup(Addr &branch_addr, void * &bp_history); + + /** + * Records that there was an unconditional branch, and modifies + * the bp history to point to an object that has the previous + * global history stored in it. + * @param bp_history Pointer that will be set to the BPHistory object. + */ + void uncondBr(void * &bp_history); /** * Updates the branch predictor with the actual result of a branch. * @param branch_addr The address of the branch to update. * @param taken Whether or not the branch was taken. + * @param bp_history Pointer to the BPHistory object that was created + * when the branch was predicted. + */ + void update(Addr &branch_addr, bool taken, void *bp_history); + + /** + * Restores the global branch history on a squash. + * @param bp_history Pointer to the BPHistory object that has the + * previous global branch history in it. */ - void update(Addr &branch_addr, unsigned global_history, bool taken); + void squash(void *bp_history); + /** Returns the global history. */ inline unsigned readGlobalHist() { return globalHistory; } private: - + /** + * Returns if the branch should be taken or not, given a counter + * value. + * @param count The counter value. + */ inline bool getPrediction(uint8_t &count); + /** + * Returns the local history index, given a branch address. + * @param branch_addr The branch's PC address. + */ inline unsigned calcLocHistIdx(Addr &branch_addr); - inline void updateHistoriesTaken(unsigned local_history_idx); + /** Updates global history as taken. */ + inline void updateGlobalHistTaken(); - inline void updateHistoriesNotTaken(unsigned local_history_idx); + /** Updates global history as not taken. */ + inline void updateGlobalHistNotTaken(); + + /** + * Updates local histories as taken. + * @param local_history_idx The local history table entry that + * will be updated. + */ + inline void updateLocalHistTaken(unsigned local_history_idx); + + /** + * Updates local histories as not taken. + * @param local_history_idx The local history table entry that + * will be updated. + */ + inline void updateLocalHistNotTaken(unsigned local_history_idx); + + /** + * The branch history information that is created upon predicting + * a branch. It will be passed back upon updating and squashing, + * when the BP can use this information to update/restore its + * state properly. + */ + struct BPHistory { +#ifdef DEBUG + BPHistory() + { newCount++; } + ~BPHistory() + { newCount--; } + + static int newCount; +#endif + unsigned globalHistory; + bool localPredTaken; + bool globalPredTaken; + bool globalUsed; + }; /** Local counters. */ std::vector<SatCounter> localCtrs; @@ -103,7 +177,6 @@ class TournamentBP /** Mask to get the proper local history. */ unsigned localHistoryMask; - /** Array of counters that make up the global predictor. */ std::vector<SatCounter> globalCtrs; @@ -122,7 +195,6 @@ class TournamentBP /** Mask to get the proper global history. */ unsigned globalHistoryMask; - /** Array of counters that make up the choice predictor. */ std::vector<SatCounter> choiceCtrs; |