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cpu: Implement per-thread GHRs

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Branch predictors that use GHRs should index them on a
per-thread basis.  This makes that so.

This is a re-spin of fb51231 after the revert (bd1c6789).
This commit is contained in:
Mitch Hayenga
2016-04-05 12:20:19 -05:00
parent 0fd4bb7f12
commit d99deff8ea
8 changed files with 110 additions and 108 deletions
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16
src/cpu/pred/bpred_unit.hh
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@@ -98,7 +98,7 @@ class BPredUnit : public SimObject
TheISA::PCState &predPC, ThreadID tid);
// @todo: Rename this function.
virtual void uncondBranch(Addr pc, void * &bp_history) = 0;
virtual void uncondBranch(ThreadID tid, Addr pc, void * &bp_history) = 0;
/**
* Tells the branch predictor to commit any updates until the given
@@ -133,7 +133,7 @@ class BPredUnit : public SimObject
* @param bp_history Pointer to the history object. The predictor
* will need to update any state and delete the object.
*/
virtual void squash(void *bp_history) = 0;
virtual void squash(ThreadID tid, void *bp_history) = 0;
/**
* Looks up a given PC in the BP to see if it is taken or not taken.
@@ -142,7 +142,7 @@ class BPredUnit : public SimObject
* has the branch predictor state associated with the lookup.
* @return Whether the branch is taken or not taken.
*/
virtual bool lookup(Addr instPC, void * &bp_history) = 0;
virtual bool lookup(ThreadID tid, Addr instPC, void * &bp_history) = 0;
/**
* If a branch is not taken, because the BTB address is invalid or missing,
@@ -152,7 +152,7 @@ class BPredUnit : public SimObject
* @param bp_history Pointer that will be set to an object that
* has the branch predictor state associated with the lookup.
*/
virtual void btbUpdate(Addr instPC, void * &bp_history) = 0;
virtual void btbUpdate(ThreadID tid, Addr instPC, void * &bp_history) = 0;
/**
* Looks up a given PC in the BTB to see if a matching entry exists.
@@ -180,15 +180,15 @@ class BPredUnit : public SimObject
* squash operation.
* @todo Make this update flexible enough to handle a global predictor.
*/
virtual void update(Addr instPC, bool taken, void *bp_history,
bool squashed) = 0;
virtual void update(ThreadID tid, Addr instPC, bool taken,
void *bp_history, bool squashed) = 0;
/**
* Deletes the associated history with a branch, performs no predictor
* updates. Used for branches that mispredict and update tables but
* are still speculative and later retire.
* @param bp_history History to delete associated with this predictor
*/
virtual void retireSquashed(void *bp_history) = 0;
virtual void retireSquashed(ThreadID tid, void *bp_history) = 0;
/**
* Updates the BTB with the target of a branch.
@@ -199,7 +199,7 @@ class BPredUnit : public SimObject
{ BTB.update(instPC, target, 0); }
virtual unsigned getGHR(void* bp_history) const { return 0; }
virtual unsigned getGHR(ThreadID tid, void* bp_history) const { return 0; }
void dump();