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#ifndef __CPU_OZONE_NULL_PREDICTOR_HH__
#define __CPU_OZONE_NULL_PREDICTOR_HH__
#include "arch/isa_traits.hh"
#include "cpu/inst_seq.hh"
template <class Impl>
class NullPredictor
{
public:
typedef typename Impl::Params Params;
typedef typename Impl::DynInstPtr DynInstPtr;
NullPredictor(Params *p) { }
struct BPredInfo {
BPredInfo()
: PC(0), nextPC(0)
{ }
BPredInfo(const Addr &pc, const Addr &next_pc)
: PC(pc), nextPC(next_pc)
{ }
Addr PC;
Addr nextPC;
};
BPredInfo lookup(Addr &PC) { return BPredInfo(PC, PC+4); }
void undo(BPredInfo &bp_info) { return; }
/**
* Predicts whether or not the instruction is a taken branch, and the
* target of the branch if it is taken.
* @param inst The branch instruction.
* @param PC The predicted PC is passed back through this parameter.
* @param tid The thread id.
* @return Returns if the branch is taken or not.
*/
bool predict(DynInstPtr &inst, Addr &PC, unsigned tid)
{ return false; }
/**
* Tells the branch predictor to commit any updates until the given
* sequence number.
* @param done_sn The sequence number to commit any older updates up until.
* @param tid The thread id.
*/
void update(const InstSeqNum &done_sn, unsigned tid) { }
/**
* Squashes all outstanding updates until a given sequence number.
* @param squashed_sn The sequence number to squash any younger updates up
* until.
* @param tid The thread id.
*/
void squash(const InstSeqNum &squashed_sn, unsigned tid) { }
/**
* Squashes all outstanding updates until a given sequence number, and
* corrects that sn's update with the proper address and taken/not taken.
* @param squashed_sn The sequence number to squash any younger updates up
* until.
* @param corr_target The correct branch target.
* @param actually_taken The correct branch direction.
* @param tid The thread id.
*/
void squash(const InstSeqNum &squashed_sn, const Addr &corr_target,
bool actually_taken, unsigned tid)
{ }
};
#endif // __CPU_OZONE_NULL_PREDICTOR_HH__
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