c2fcac7c0d
cpu/base_dyn_inst.cc:
Remove unused commented out code.
cpu/base_dyn_inst.hh:
Fix up comments.
cpu/beta_cpu/2bit_local_pred.cc:
Reorder code to match header file.
cpu/beta_cpu/2bit_local_pred.hh:
Update comments.
cpu/beta_cpu/alpha_dyn_inst.hh:
Remove useless comments.
cpu/beta_cpu/alpha_dyn_inst_impl.hh:
cpu/beta_cpu/alpha_full_cpu_impl.hh:
cpu/beta_cpu/comm.hh:
cpu/beta_cpu/iew_impl.hh:
Remove unused commented code.
cpu/beta_cpu/alpha_full_cpu.hh:
Remove obsolete comment.
cpu/beta_cpu/alpha_impl.hh:
cpu/beta_cpu/full_cpu.hh:
Alphabetize includes.
cpu/beta_cpu/bpred_unit.hh:
Remove unused global history code.
cpu/beta_cpu/btb.hh:
cpu/beta_cpu/free_list.hh:
Use full path in #defines.
cpu/beta_cpu/commit.hh:
cpu/beta_cpu/decode.hh:
Reorder functions.
cpu/beta_cpu/commit_impl.hh:
Remove obsolete commented code.
cpu/beta_cpu/fetch.hh:
Remove obsolete comments.
cpu/beta_cpu/fetch_impl.hh:
cpu/beta_cpu/rename_impl.hh:
Remove commented code.
cpu/beta_cpu/full_cpu.cc:
Remove useless defines.
cpu/beta_cpu/inst_queue.hh:
Use full path for #defines.
cpu/beta_cpu/inst_queue_impl.hh:
Reorder functions to match header file.
cpu/beta_cpu/mem_dep_unit.hh:
Use full path name for #defines.
cpu/beta_cpu/ras.hh:
Use full path names for #defines. Remove mod operation.
cpu/beta_cpu/regfile.hh:
Remove unused commented code, fix up current comments.
cpu/beta_cpu/tournament_pred.cc:
cpu/beta_cpu/tournament_pred.hh:
Update programming style.
--HG--
extra : convert_revision : fb9d18a853f58a1108ff827e3c123d5b52a0608a
102 lines
2.7 KiB
C++
102 lines
2.7 KiB
C++
#include "base/trace.hh"
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#include "cpu/beta_cpu/2bit_local_pred.hh"
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DefaultBP::DefaultBP(unsigned _localPredictorSize,
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unsigned _localCtrBits,
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unsigned _instShiftAmt)
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: localPredictorSize(_localPredictorSize),
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localCtrBits(_localCtrBits),
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instShiftAmt(_instShiftAmt)
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{
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// Should do checks here to make sure sizes are correct (powers of 2).
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// Setup the index mask.
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indexMask = localPredictorSize - 1;
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DPRINTF(Fetch, "Branch predictor: index mask: %#x\n", indexMask);
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// Setup the array of counters for the local predictor.
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localCtrs = new SatCounter[localPredictorSize];
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for (int i = 0; i < localPredictorSize; ++i)
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localCtrs[i].setBits(_localCtrBits);
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DPRINTF(Fetch, "Branch predictor: local predictor size: %i\n",
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localPredictorSize);
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DPRINTF(Fetch, "Branch predictor: local counter bits: %i\n", localCtrBits);
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DPRINTF(Fetch, "Branch predictor: instruction shift amount: %i\n",
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instShiftAmt);
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}
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bool
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DefaultBP::lookup(Addr &branch_addr)
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{
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bool taken;
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uint8_t local_prediction;
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unsigned local_predictor_idx = getLocalIndex(branch_addr);
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DPRINTF(Fetch, "Branch predictor: Looking up index %#x\n",
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local_predictor_idx);
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assert(local_predictor_idx < localPredictorSize);
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local_prediction = localCtrs[local_predictor_idx].read();
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DPRINTF(Fetch, "Branch predictor: prediction is %i.\n",
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(int)local_prediction);
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taken = getPrediction(local_prediction);
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#if 0
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// Speculative update.
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if (taken) {
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DPRINTF(Fetch, "Branch predictor: Branch updated as taken.\n");
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localCtrs[local_predictor_idx].increment();
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} else {
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DPRINTF(Fetch, "Branch predictor: Branch updated as not taken.\n");
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localCtrs[local_predictor_idx].decrement();
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}
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#endif
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return taken;
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}
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void
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DefaultBP::update(Addr &branch_addr, bool taken)
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{
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unsigned local_predictor_idx;
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// Update the local predictor.
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local_predictor_idx = getLocalIndex(branch_addr);
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DPRINTF(Fetch, "Branch predictor: Looking up index %#x\n",
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local_predictor_idx);
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assert(local_predictor_idx < localPredictorSize);
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if (taken) {
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DPRINTF(Fetch, "Branch predictor: Branch updated as taken.\n");
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localCtrs[local_predictor_idx].increment();
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} else {
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DPRINTF(Fetch, "Branch predictor: Branch updated as not taken.\n");
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localCtrs[local_predictor_idx].decrement();
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}
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}
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inline
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bool
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DefaultBP::getPrediction(uint8_t &count)
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{
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// Get the MSB of the count
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return (count >> (localCtrBits - 1));
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}
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inline
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unsigned
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DefaultBP::getLocalIndex(Addr &branch_addr)
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{
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return (branch_addr >> instShiftAmt) & indexMask;
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}
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