gem5/cpu/o3/bpred_unit_impl.hh
Gabe Black 463aa6d49d Changes to untemplate StaticInst and StaticInstPtr, change the isa to a namespace instead of a class, an improvement to the architecture specific header file selection system, and fixed up a few include paths.
arch/alpha/alpha_linux_process.cc:
    Added using directive for AlphaISA namespace
arch/alpha/alpha_memory.hh:
arch/alpha/isa/branch.isa:
cpu/pc_event.hh:
    Added typedefs for Addr
arch/alpha/alpha_tru64_process.cc:
arch/alpha/arguments.cc:
    Added using directive for AlphaISA
arch/alpha/ev5.hh:
    Added an include of arch/alpha/isa_traits.hh, and a using directive for the AlphaISA namespace.
arch/alpha/faults.hh:
    Added a typedef for the Addr type, and changed the formatting of the faults slightly.
arch/alpha/isa/main.isa:
    Untemplatized StaticInst, added a using for namespace AlphaISA to show up in decoder.cc and the exec.ccs, relocated makeNop to decoder.hh
arch/alpha/isa/mem.isa:
    Untemplatized StaticInst and StaticInstPtr
arch/alpha/isa/pal.isa:
cpu/base_dyn_inst.cc:
    Untemplatized StaticInstPtr
arch/alpha/isa_traits.hh:
    Changed variables to be externs instead of static since they are part of a namespace and not a class.
arch/alpha/stacktrace.cc:
    Untemplatized StaticInstPtr, and added a using directive for AlphaISA.
arch/alpha/stacktrace.hh:
    Added some typedefs for Addr and MachInst, and untemplatized StaticInstPtr
arch/alpha/vtophys.cc:
    Added a using directive for AlphaISA
arch/alpha/vtophys.hh:
    Added the AlphaISA namespace specifier where needed
arch/isa_parser.py:
    Changed the placement of the definition of the decodeInst function to be outside the namespaceInst namespace.
base/loader/object_file.hh:
cpu/o3/bpred_unit.hh:
    Added a typedef for Addr
base/loader/symtab.hh:
    Added a typedef for Addr, and added a TheISA to Addr in another typedef
base/remote_gdb.cc:
    Added a using namespace TheISA, and untemplatized StaticInstPtr
base/remote_gdb.hh:
    Added typedefs for Addr and MachInst
cpu/base.cc:
    Added TheISA specifier to some variables exported from the isa.
cpu/base.hh:
    Added a typedef for Addr, and TheISA to some variables from the ISA
cpu/base_dyn_inst.hh:
    Untemplatized StaticInstPtr, and added TheISA specifier to some variables from the ISA.
cpu/exec_context.hh:
    Added some typedefs for types from the isa, and added TheISA specifier to some variables from the isa
cpu/exetrace.hh:
    Added typedefs for some types from the ISA, and untemplatized StaticInstPtr
cpu/memtest/memtest.cc:
cpu/o3/btb.cc:
dev/baddev.cc:
dev/ide_ctrl.cc:
dev/ide_disk.cc:
dev/isa_fake.cc:
dev/ns_gige.cc:
dev/pciconfigall.cc:
dev/platform.cc:
dev/sinic.cc:
dev/uart8250.cc:
kern/freebsd/freebsd_system.cc:
kern/linux/linux_system.cc:
kern/system_events.cc:
kern/tru64/dump_mbuf.cc:
kern/tru64/tru64_events.cc:
sim/process.cc:
sim/pseudo_inst.cc:
sim/system.cc:
    Added using namespace TheISA
cpu/memtest/memtest.hh:
cpu/trace/opt_cpu.hh:
cpu/trace/reader/itx_reader.hh:
dev/ide_disk.hh:
dev/pcidev.hh:
dev/platform.hh:
dev/tsunami.hh:
sim/system.hh:
sim/vptr.hh:
    Added typedef for Addr
cpu/o3/2bit_local_pred.hh:
    Changed the include to use arch/isa_traits.hh instead of arch/alpha/isa_traits.hh. Added typedef for Addr
cpu/o3/alpha_cpu.hh:
    Added typedefs for Addr and IntReg
cpu/o3/alpha_cpu_impl.hh:
    Added this-> to setNextPC to fix a problem since it didn't depend on template parameters any more. Removed "typename" where it was no longer needed.
cpu/o3/alpha_dyn_inst.hh:
    Cleaned up some typedefs, and untemplatized StaticInst
cpu/o3/alpha_dyn_inst_impl.hh:
    untemplatized StaticInstPtr
cpu/o3/alpha_impl.hh:
    Fixed up a typedef of MachInst
cpu/o3/bpred_unit_impl.hh:
    Added a using TheISA::MachInst to a function
cpu/o3/btb.hh:
    Changed an include from arch/alpha/isa_traits.hh to arch/isa_traits.hh, and added a typedef for Addr
cpu/o3/commit.hh:
    Removed a typedef of Impl::ISA as ISA, since TheISA takes care of this now.
cpu/o3/cpu.cc:
    Cleaned up namespace issues
cpu/o3/cpu.hh:
    Cleaned up namespace usage
cpu/o3/decode.hh:
    Removed typedef of ISA, and changed it to TheISA
cpu/o3/fetch.hh:
    Fized up typedefs, and changed ISA to TheISA
cpu/o3/free_list.hh:
    Changed include of arch/alpha/isa_traits.hh to arch/isa_traits.hh
cpu/o3/iew.hh:
    Removed typedef of ISA
cpu/o3/iew_impl.hh:
    Added TheISA namespace specifier to MachInst
cpu/o3/ras.hh:
    Changed include from arch/alpha/isa_traits.hh to arch/isa_traits.hh, and added a typedef for Addr.
cpu/o3/regfile.hh:
    Changed ISA to TheISA, and added some typedefs for Addr, IntReg, FloatReg, and MiscRegFile
cpu/o3/rename.hh:
    Changed ISA to TheISA, and added a typedef for RegIndex
cpu/o3/rename_map.hh:
    Added an include for arch/isa_traits.hh, and a typedef for RegIndex
cpu/o3/rob.hh:
    Added a typedef for RegIndex
cpu/o3/store_set.hh:
cpu/o3/tournament_pred.hh:
    Changed an include of arch/alpha/isa_traits.hh to arch/isa_traits.hh, and added a typedef of Addr
cpu/ozone/cpu.hh:
    Changed ISA into TheISA, and untemplatized StaticInst
cpu/pc_event.cc:
    Added namespace specifier TheISA to Addr types
cpu/profile.hh:
kern/kernel_stats.hh:
    Added typedef for Addr, and untemplatized StaticInstPtr
cpu/simple/cpu.cc:
    Changed using directive from LittleEndianGuest to AlphaISA, which will contain both namespaces. Added TheISA where needed, and untemplatized StaticInst
cpu/simple/cpu.hh:
    Added a typedef for MachInst, and untemplatized StaticInst
cpu/static_inst.cc:
    Untemplatized StaticInst
cpu/static_inst.hh:
    Untemplatized StaticInst by using the TheISA namespace
dev/alpha_console.cc:
    Added using namespace AlphaISA
dev/simple_disk.hh:
    Added typedef for Addr and fixed up some formatting
dev/sinicreg.hh:
    Added TheISA namespace specifier where needed
dev/tsunami.cc:
dev/tsunami_io.cc:
dev/tsunami_pchip.cc:
    Added using namespace TheISA. It might be better for it to be AlphaISA
dev/tsunami_cchip.cc:
    Added typedef for TheISA. It might be better for it to be AlphaISA
kern/linux/aligned.hh:
sim/pseudo_inst.hh:
    Added TheISA namespace specifier to Addr
kern/linux/linux_threadinfo.hh:
    Added typedef for Addr, and TheISA namespace specifier to StackPointerReg
kern/tru64/mbuf.hh:
    Added TheISA to Addr type in structs
sim/process.hh:
    Added typedefs of Addr, RegFile, and MachInst
sim/syscall_emul.cc:
    Added using namespace TheISA, and a cast of VMPageSize to the int type
sim/syscall_emul.hh:
    Added typecast for Addr, and TheISA namespace specifier for where needed

--HG--
extra : convert_revision : 91d4f6ca33a73b21c1f1771d74bfdea3b80eff45
2006-02-19 02:34:37 -05:00

276 lines
8.4 KiB
C++

/*
* Copyright (c) 2004-2005 The Regents of The University of Michigan
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met: redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer;
* redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution;
* neither the name of the copyright holders nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "base/trace.hh"
#include "base/traceflags.hh"
#include "cpu/o3/bpred_unit.hh"
template<class Impl>
TwobitBPredUnit<Impl>::TwobitBPredUnit(Params &params)
: BP(params.local_predictor_size,
params.local_ctr_bits,
params.instShiftAmt),
BTB(params.BTBEntries,
params.BTBTagSize,
params.instShiftAmt),
RAS(params.RASSize)
{
}
template <class Impl>
void
TwobitBPredUnit<Impl>::regStats()
{
lookups
.name(name() + ".BPredUnit.lookups")
.desc("Number of BP lookups")
;
condPredicted
.name(name() + ".BPredUnit.condPredicted")
.desc("Number of conditional branches predicted")
;
condIncorrect
.name(name() + ".BPredUnit.condIncorrect")
.desc("Number of conditional branches incorrect")
;
BTBLookups
.name(name() + ".BPredUnit.BTBLookups")
.desc("Number of BTB lookups")
;
BTBHits
.name(name() + ".BPredUnit.BTBHits")
.desc("Number of BTB hits")
;
BTBCorrect
.name(name() + ".BPredUnit.BTBCorrect")
.desc("Number of correct BTB predictions (this stat may not "
"work properly.")
;
usedRAS
.name(name() + ".BPredUnit.usedRAS")
.desc("Number of times the RAS was used.")
;
RASIncorrect
.name(name() + ".BPredUnit.RASInCorrect")
.desc("Number of incorrect RAS predictions.")
;
}
template <class Impl>
bool
TwobitBPredUnit<Impl>::predict(DynInstPtr &inst, Addr &PC)
{
// See if branch predictor predicts taken.
// If so, get its target addr either from the BTB or the RAS.
// Once that's done, speculatively update the predictor?
// Save off record of branch stuff so the RAS can be fixed
// up once it's done.
using TheISA::MachInst;
bool pred_taken = false;
Addr target;
++lookups;
if (inst->isUncondCtrl()) {
DPRINTF(Fetch, "BranchPred: Unconditional control.\n");
pred_taken = true;
} else {
++condPredicted;
pred_taken = BPLookup(PC);
DPRINTF(Fetch, "BranchPred: Branch predictor predicted %i for PC %#x"
"\n", pred_taken, inst->readPC());
}
PredictorHistory predict_record(inst->seqNum, PC, pred_taken);
// Now lookup in the BTB or RAS.
if (pred_taken) {
if (inst->isReturn()) {
++usedRAS;
// If it's a function return call, then look up the address
// in the RAS.
target = RAS.top();
// Record the top entry of the RAS, and its index.
predict_record.usedRAS = true;
predict_record.RASIndex = RAS.topIdx();
predict_record.RASTarget = target;
RAS.pop();
DPRINTF(Fetch, "BranchPred: Instruction %#x is a return, RAS "
"predicted target: %#x, RAS index: %i.\n",
inst->readPC(), target, predict_record.RASIndex);
} else {
++BTBLookups;
if (inst->isCall()) {
RAS.push(PC+sizeof(MachInst));
// Record that it was a call so that the top RAS entry can
// be popped off if the speculation is incorrect.
predict_record.wasCall = true;
DPRINTF(Fetch, "BranchPred: Instruction %#x was a call, "
"adding %#x to the RAS.\n",
inst->readPC(), PC+sizeof(MachInst));
}
if (BTB.valid(PC)) {
++BTBHits;
//If it's anything else, use the BTB to get the target addr.
target = BTB.lookup(PC);
DPRINTF(Fetch, "BranchPred: Instruction %#x predicted target "
"is %#x.\n", inst->readPC(), target);
} else {
DPRINTF(Fetch, "BranchPred: BTB doesn't have a valid entry."
"\n");
pred_taken = false;
}
}
}
if (pred_taken) {
// Set the PC and the instruction's predicted target.
PC = target;
inst->setPredTarg(target);
} else {
PC = PC + sizeof(MachInst);
inst->setPredTarg(PC);
}
predHist.push_front(predict_record);
assert(!predHist.empty());
return pred_taken;
}
template <class Impl>
void
TwobitBPredUnit<Impl>::update(const InstSeqNum &done_sn)
{
DPRINTF(Fetch, "BranchPred: Commiting branches until sequence number "
"%i.\n", done_sn);
while (!predHist.empty() && predHist.back().seqNum <= done_sn) {
assert(!predHist.empty());
// Update the branch predictor with the correct results of branches.
BP.update(predHist.back().PC, predHist.back().predTaken);
predHist.pop_back();
}
}
template <class Impl>
void
TwobitBPredUnit<Impl>::squash(const InstSeqNum &squashed_sn)
{
while (!predHist.empty() && predHist.front().seqNum > squashed_sn) {
if (predHist.front().usedRAS) {
DPRINTF(Fetch, "BranchPred: Restoring top of RAS to: %i, "
"target: %#x.\n",
predHist.front().RASIndex,
predHist.front().RASTarget);
RAS.restore(predHist.front().RASIndex,
predHist.front().RASTarget);
} else if (predHist.front().wasCall) {
DPRINTF(Fetch, "BranchPred: Removing speculative entry added "
"to the RAS.\n");
RAS.pop();
}
predHist.pop_front();
}
}
template <class Impl>
void
TwobitBPredUnit<Impl>::squash(const InstSeqNum &squashed_sn,
const Addr &corr_target,
const bool actually_taken)
{
// Now that we know that a branch was mispredicted, we need to undo
// all the branches that have been seen up until this branch and
// fix up everything.
++condIncorrect;
DPRINTF(Fetch, "BranchPred: Squashing from sequence number %i, "
"setting target to %#x.\n",
squashed_sn, corr_target);
while (!predHist.empty() && predHist.front().seqNum > squashed_sn) {
if (predHist.front().usedRAS) {
DPRINTF(Fetch, "BranchPred: Restoring top of RAS to: %i, "
"target: %#x.\n",
predHist.front().RASIndex,
predHist.front().RASTarget);
RAS.restore(predHist.front().RASIndex,
predHist.front().RASTarget);
} else if (predHist.front().wasCall) {
DPRINTF(Fetch, "BranchPred: Removing speculative entry added "
"to the RAS.\n");
RAS.pop();
}
predHist.pop_front();
}
predHist.front().predTaken = actually_taken;
if (predHist.front().usedRAS) {
++RASIncorrect;
}
BP.update(predHist.front().PC, actually_taken);
BTB.update(predHist.front().PC, corr_target);
}