gem5/src/cpu/minor/func_unit.hh

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/*
* Copyright (c) 2013-2014 ARM Limited
* All rights reserved
*
* The license below extends only to copyright in the software and shall
* not be construed as granting a license to any other intellectual
* property including but not limited to intellectual property relating
* to a hardware implementation of the functionality of the software
* licensed hereunder. You may use the software subject to the license
* terms below provided that you ensure that this notice is replicated
* unmodified and in its entirety in all distributions of the software,
* modified or unmodified, in source code or in binary form.
*
* 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: Andrew Bardsley
*/
/**
* @file
*
* Execute function unit descriptions and pipeline implementations.
*/
#ifndef __CPU_MINOR_FUNC_UNIT_HH__
#define __CPU_MINOR_FUNC_UNIT_HH__
#include "cpu/minor/buffers.hh"
#include "cpu/minor/dyn_inst.hh"
#include "cpu/func_unit.hh"
#include "cpu/timing_expr.hh"
#include "params/MinorFU.hh"
#include "params/MinorFUPool.hh"
#include "params/MinorOpClass.hh"
#include "params/MinorOpClassSet.hh"
#include "sim/clocked_object.hh"
/** Boxing for MinorOpClass to get around a build problem with C++11 but
* also allow for future additions to op class checking */
class MinorOpClass : public SimObject
{
public:
OpClass opClass;
public:
MinorOpClass(const MinorOpClassParams *params) :
SimObject(params),
opClass(params->opClass)
{ }
};
/** Wrapper for a matchable set of op classes */
class MinorOpClassSet : public SimObject
{
public:
std::vector<MinorOpClass *> opClasses;
/** Convenience packing of opClasses into a bit vector for easier
* testing */
std::vector<bool> capabilityList;
public:
MinorOpClassSet(const MinorOpClassSetParams *params);
public:
/** Does this set support the given op class */
bool provides(OpClass op_class) { return capabilityList[op_class]; }
};
/** Extra timing capability to allow individual ops to have their source
* register dependency latencies tweaked based on the ExtMachInst of the
* source instruction.
*/
class MinorFUTiming: public SimObject
{
public:
/** Mask off the ExtMachInst of an instruction before comparing with
* match */
uint64_t mask;
uint64_t match;
/** Textual description of the decode's purpose */
std::string description;
/** If true, instructions matching this mask/match should *not* be
* issued in this FU */
bool suppress;
/** Extra latency that the instruction should spend at the end of
* the pipeline */
Cycles extraCommitLat;
TimingExpr *extraCommitLatExpr;
/** Extra delay that results should show in the scoreboard after
* leaving the pipeline. If set to Cycles(0) for memory references,
* an 'unpredictable' return time will be set in the scoreboard
* blocking following dependent instructions from issuing */
Cycles extraAssumedLat;
/** Cycle offsets from the scoreboard delivery times of register values
* for each of this instruction's source registers (in srcRegs order).
* The offsets are subtracted from the scoreboard returnCycle times.
* For example, for an instruction type with 3 source registers,
* [2, 1, 2] will allow the instruction to issue upto 2 cycles early
* for dependencies on the 1st and 3rd register and upto 1 cycle early
* on the 2nd. */
std::vector<Cycles> srcRegsRelativeLats;
/** Extra opClasses check (after the FU one) */
MinorOpClassSet *opClasses;
public:
MinorFUTiming(const MinorFUTimingParams *params);
public:
/** Does the extra decode in this object support the given op class */
bool provides(OpClass op_class) { return opClasses->provides(op_class); }
};
/** A functional unit that can execute any of opClasses operations with a
* single op(eration)Lat(ency) and issueLat(ency) associated with the unit
* rather than each operation (as in src/FuncUnit).
*
* This is very similar to cpu/func_unit but replicated here to allow
* the Minor functional units to change without having to disturb the common
* definition.
*/
class MinorFU : public SimObject
{
public:
MinorOpClassSet *opClasses;
/** Delay from issuing the operation, to it reaching the
* end of the associated pipeline */
Cycles opLat;
/** Delay after issuing an operation before the next
* operation can be issued */
Cycles issueLat;
/** FUs which this pipeline can't receive a forwarded (i.e. relative
* latency != 0) result from */
std::vector<unsigned int> cantForwardFromFUIndices;
/** Extra timing info to give timings to individual ops */
std::vector<MinorFUTiming *> timings;
public:
MinorFU(const MinorFUParams *params) :
SimObject(params),
opClasses(params->opClasses),
opLat(params->opLat),
issueLat(params->issueLat),
cantForwardFromFUIndices(params->cantForwardFromFUIndices),
timings(params->timings)
{ }
};
/** A collection of MinorFUs */
class MinorFUPool : public SimObject
{
public:
std::vector<MinorFU *> funcUnits;
public:
MinorFUPool(const MinorFUPoolParams *params) :
SimObject(params),
funcUnits(params->funcUnits)
{ }
};
namespace Minor
{
/** Container class to box instructions in the FUs to make those
* queues have correct bubble behaviour when stepped */
class QueuedInst
{
public:
MinorDynInstPtr inst;
public:
QueuedInst(MinorDynInstPtr inst_ = MinorDynInst::bubble()) :
inst(inst_)
{ }
public:
/** Report and bubble interfaces */
void reportData(std::ostream &os) const;
bool isBubble() const { return inst->isBubble(); }
static QueuedInst bubble()
{ return QueuedInst(MinorDynInst::bubble()); }
};
/** Functional units have pipelines which stall when an inst gets to
* their ends allowing Execute::commit to pick up timing-completed insts
* when it feels like it */
typedef SelfStallingPipeline<QueuedInst,
ReportTraitsAdaptor<QueuedInst> > FUPipelineBase;
/** A functional unit configured from a MinorFU object */
class FUPipeline : public FUPipelineBase, public FuncUnit
{
public:
/** Functional unit description that this pipeline implements */
const MinorFU &description;
/** An FUPipeline needs access to curCycle, use this timing source */
ClockedObject &timeSource;
/** Set of operation classes supported by this FU */
std::bitset<Num_OpClasses> capabilityList;
/** FUs which this pipeline can't receive a forwarded (i.e. relative
* latency != 0) result from */
std::vector<bool> cantForwardFromFUIndices;
public:
/** When can a new instruction be inserted into the pipeline? This is
* an absolute cycle time unless it is 0 in which case the an
* instruction can be pushed straightaway */
Cycles nextInsertCycle;
public:
FUPipeline(const std::string &name, const MinorFU &description_,
ClockedObject &timeSource_);
public:
/** How many cycles must from curCycle before insertion into the
* pipeline is allowed */
Cycles cyclesBeforeInsert();
/** Can an instruction be inserted now? */
bool canInsert() const;
/** Find the extra timing information for this instruction. Returns
* NULL if no decode info. is found */
MinorFUTiming *findTiming(const StaticInstPtr &inst);
/** Step the pipeline. Allow multiple steps? */
void advance();
};
}
#endif /* __CPU_MINOR_FUNC_UNIT_HH__ */