/*
* Copyright (c) 2007 MIPS Technologies, Inc.
* 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.
*
* Authors: Korey Sewell
*
*/
#include <list>
#include <vector>
#include "cpu/inorder/resources/execution_unit.hh"
#include "cpu/inorder/cpu.hh"
#include "cpu/inorder/resource_pool.hh"
#include "debug/Fault.hh"
#include "debug/InOrderExecute.hh"
#include "debug/InOrderStall.hh"
#include "sim/full_system.hh"
using namespace std;
using namespace ThePipeline;
ExecutionUnit::ExecutionUnit(string res_name, int res_id, int res_width,
int res_latency, InOrderCPU *_cpu,
ThePipeline::Params *params)
: Resource(res_name, res_id, res_width, res_latency, _cpu),
lastExecuteTick(0), lastControlTick(0)
{ }
void
ExecutionUnit::regStats()
{
predictedTakenIncorrect
.name(name() + ".predictedTakenIncorrect")
.desc("Number of Branches Incorrectly Predicted As Taken.");
predictedNotTakenIncorrect
.name(name() + ".predictedNotTakenIncorrect")
.desc("Number of Branches Incorrectly Predicted As Not Taken).");
executions
.name(name() + ".executions")
.desc("Number of Instructions Executed.");
predictedIncorrect
.name(name() + ".mispredicted")
.desc("Number of Branches Incorrectly Predicted");
predictedCorrect
.name(name() + ".predicted")
.desc("Number of Branches Incorrectly Predicted");
mispredictPct
.name(name() + ".mispredictPct")
.desc("Percentage of Incorrect Branches Predicts")
.precision(6);
mispredictPct = (predictedIncorrect /
(predictedCorrect + predictedIncorrect)) * 100;
Resource::regStats();
}
void
ExecutionUnit::execute(int slot_num)
{
ResourceRequest* exec_req = reqs[slot_num];
DynInstPtr inst = reqs[slot_num]->inst;
if (inst->fault != NoFault) {
DPRINTF(InOrderExecute,
"[tid:%i]: [sn:%i]: Detected %s fault @ %x. Forwarding to "
"next stage.\n", inst->readTid(), inst->seqNum, inst->fault->name(),
inst->pcState());
exec_req->done();
return;
}
Fault fault = NoFault;
Tick cur_tick = curTick();
unsigned stage_num = exec_req->getStageNum();
ThreadID tid = inst->readTid();
#if TRACING_ON
InstSeqNum seq_num = inst->seqNum;
#endif
switch (exec_req->cmd)
{
case ExecuteInst:
{
if (inst->isNop()) {
DPRINTF(InOrderExecute, "[tid:%i] [sn:%i] [PC:%s] Ignoring execution"
"of %s.\n", inst->readTid(), seq_num, inst->pcState(),
inst->instName());
inst->setExecuted();
exec_req->done();
return;
} else {
DPRINTF(InOrderExecute, "[tid:%i] Executing [sn:%i] [PC:%s] %s.\n",
inst->readTid(), seq_num, inst->pcState(), inst->instName());
}
if (cur_tick != lastExecuteTick) {
lastExecuteTick = cur_tick;
}
//@todo: handle address generation here
assert(!inst->isMemRef());
if (inst->isControl()) {
if (lastControlTick == cur_tick) {
DPRINTF(InOrderExecute, "Can not Execute More than One Control "
"Inst Per Cycle. Blocking Request.\n");
exec_req->done(false);
return;
}
lastControlTick = curTick();
// Evaluate Branch
fault = inst->execute();
// Should unconditional control , pc relative count as an
// execution??? Probably not.
executions++;
if (fault == NoFault) {
inst->setExecuted();
if (inst->mispredicted()) {
assert(inst->isControl());
// Set up Squash Generated By this Misprediction
TheISA::PCState pc = inst->pcState();
TheISA::advancePC(pc, inst->staticInst);
inst->setPredTarg(pc);
inst->setSquashInfo(stage_num);
setupSquash(inst, stage_num, tid);
DPRINTF(InOrderExecute, "[tid:%i]: [sn:%i] Squashing from "
"stage %i. Redirecting fetch to %s.\n", tid,
inst->seqNum, stage_num, pc);
DPRINTF(InOrderStall, "STALL: [tid:%i]: Branch"
" misprediction at %s\n", tid, inst->pcState());
if (inst->predTaken()) {
predictedTakenIncorrect++;
DPRINTF(InOrderExecute, "[tid:%i] [sn:%i] %s ..."
"PC %s ... Mispredicts! "
"(Prediction: Taken)\n",
tid, inst->seqNum,
inst->staticInst->disassemble(
inst->instAddr()),
inst->pcState());
} else {
predictedNotTakenIncorrect++;
DPRINTF(InOrderExecute, "[tid:%i] [sn:%i] %s ..."
"PC %s ... Mispredicts! "
"(Prediction: Not Taken)\n",
tid, inst->seqNum,
inst->staticInst->disassemble(
inst->instAddr()),
inst->pcState());
}
predictedIncorrect++;
} else {
DPRINTF(InOrderExecute, "[tid:%i]: [sn:%i]: Prediction"
"Correct.\n", inst->readTid(), seq_num);
predictedCorrect++;
}
exec_req->done();
} else {
DPRINTF(Fault, "[tid:%i]:[sn:%i]: Fault %s found\n",
inst->readTid(), inst->seqNum, fault->name());
inst->fault = fault;
exec_req->done();
}
} else {
// Regular ALU instruction
fault = inst->execute();
executions++;
if (fault == NoFault) {
inst->setExecuted();
#if TRACING_ON
for (int didx = 0; didx < inst->numDestRegs(); didx++)
if (inst->resultType(didx) == InOrderDynInst::Float ||
inst->resultType(didx) == InOrderDynInst::FloatBits ||
inst->resultType(didx) == InOrderDynInst::Double)
DPRINTF(InOrderExecute, "[tid:%i]: [sn:%i]: Dest result %i "
"of FP execution is %08f (%x).\n", inst->readTid(),
seq_num, didx, inst->readFloatResult(didx),
inst->readFloatBitsResult(didx));
else
DPRINTF(InOrderExecute, "[tid:%i]: [sn:%i]: Dest result %i "
"of Int execution is 0x%x.\n", inst->readTid(),
seq_num, didx, inst->readIntResult(didx));
#endif
if (!FullSystem) {
// The Syscall might change the PC, so conservatively
// squash everything behing it
if (inst->isSyscall()) {
inst->setSquashInfo(stage_num);
setupSquash(inst, stage_num, tid);
}
}
} else {
DPRINTF(InOrderExecute, "[tid:%i]: [sn:%i]: had a %s "
"fault.\n", inst->readTid(), seq_num, fault->name());
DPRINTF(Fault, "[tid:%i]:[sn:%i]: Fault %s found\n",
inst->readTid(), inst->seqNum, fault->name());
inst->fault = fault;
}
exec_req->done();
}
}
break;
default:
fatal("Unrecognized command to %s", resName);
}
}