src/cpu/minor/func_unit.hh - arm/gem5 - Git at Google

 /*
  * 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__ */
	/*
	* 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__ */