rename_map.hh

来自「linux下基于c++的处理器仿真平台。具有处理器流水线」· HH 代码 · 共 173 行

/*
 * Copyright (c) 2004, 2005
 * The Regents of The University of Michigan
 * All Rights Reserved
 *
 * This code is part of the M5 simulator, developed by Nathan Binkert,
 * Erik Hallnor, Steve Raasch, and Steve Reinhardt, with contributions
 * from Ron Dreslinski, Dave Greene, Lisa Hsu, Kevin Lim, Ali Saidi, 
 * and Andrew Schultz.
 *
 * Permission is granted to use, copy, create derivative works and
 * redistribute this software and such derivative works for any
 * purpose, so long as the copyright notice above, this grant of
 * permission, and the disclaimer below appear in all copies made; and
 * so long as the name of The University of Michigan is not used in
 * any advertising or publicity pertaining to the use or distribution
 * of this software without specific, written prior authorization.
 *
 * THIS SOFTWARE IS PROVIDED AS IS, WITHOUT REPRESENTATION FROM THE
 * UNIVERSITY OF MICHIGAN AS TO ITS FITNESS FOR ANY PURPOSE, AND
 * WITHOUT WARRANTY BY THE UNIVERSITY OF MICHIGAN OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE. THE REGENTS OF THE UNIVERSITY OF MICHIGAN SHALL NOT BE
 * LIABLE FOR ANY DAMAGES, INCLUDING DIRECT, SPECIAL, INDIRECT,
 * INCIDENTAL, OR CONSEQUENTIAL DAMAGES, WITH RESPECT TO ANY CLAIM
 * ARISING OUT OF OR IN CONNECTION WITH THE USE OF THE SOFTWARE, EVEN
 * IF IT HAS BEEN OR IS HEREAFTER ADVISED OF THE POSSIBILITY OF SUCH
 * DAMAGES.
 */

// Todo:  Create destructor.
// Have it so that there's a more meaningful name given to the variable 
// that marks the beginning of the FP registers.

#ifndef __CPU_O3_CPU_RENAME_MAP_HH__
#define __CPU_O3_CPU_RENAME_MAP_HH__

#include <iostream>
#include <utility>
#include <vector>

#include "cpu/o3/free_list.hh"

class SimpleRenameMap
{ 
  public:
    /**
     * Pair of a logical register and a physical register.  Tells the
     * previous mapping of a logical register to a physical register.  
     * Used to roll back the rename map to a previous state.
     */
    typedef std::pair<RegIndex, PhysRegIndex> UnmapInfo;

    /**
     * Pair of a physical register and a physical register.  Used to
     * return the physical register that a logical register has been
     * renamed to, and the previous physical register that the same
     * logical register was previously mapped to.
     */
    typedef std::pair<PhysRegIndex, PhysRegIndex> RenameInfo;

  public:
    //Constructor
    SimpleRenameMap(unsigned _numLogicalIntRegs,
                    unsigned _numPhysicalIntRegs,
                    unsigned _numLogicalFloatRegs,
                    unsigned _numPhysicalFloatRegs,
                    unsigned _numMiscRegs,
                    RegIndex _intZeroReg,
                    RegIndex _floatZeroReg);

    /** Destructor. */
    ~SimpleRenameMap();

    void setFreeList(SimpleFreeList *fl_ptr);

    //Tell rename map to get a free physical register for a given
    //architected register.  Not sure it should have a return value,
    //but perhaps it should have some sort of fault in case there are
    //no free registers.
    RenameInfo rename(RegIndex arch_reg);

    PhysRegIndex lookup(RegIndex phys_reg);
    
    bool isReady(PhysRegIndex arch_reg);
    
    /** 
     * Marks the given register as ready, meaning that its value has been
     * calculated and written to the register file.
     * @param ready_reg The index of the physical register that is now ready.
     */
    void markAsReady(PhysRegIndex ready_reg);

    void setEntry(RegIndex arch_reg, PhysRegIndex renamed_reg);

    void squash(std::vector<RegIndex> freed_regs,
                std::vector<UnmapInfo> unmaps);

    int numFreeEntries();

  private:
    /** Number of logical integer registers. */
    int numLogicalIntRegs;

    /** Number of physical integer registers. */
    int numPhysicalIntRegs;

    /** Number of logical floating point registers. */
    int numLogicalFloatRegs;

    /** Number of physical floating point registers. */
    int numPhysicalFloatRegs;

    /** Number of miscellaneous registers. */
    int numMiscRegs;

    /** Number of logical integer + float registers. */
    int numLogicalRegs;

    /** Number of physical integer + float registers. */
    int numPhysicalRegs;

    /** The integer zero register.  This implementation assumes it is always
     *  zero and never can be anything else.
     */
    RegIndex intZeroReg;

    /** The floating point zero register.  This implementation assumes it is 
     *  always zero and never can be anything else.
     */
    RegIndex floatZeroReg;

    class RenameEntry
    {
      public:
        PhysRegIndex physical_reg;
        bool valid;
        
        RenameEntry()
            : physical_reg(0), valid(false)
        { }
    };

    /** Integer rename map. */
    RenameEntry *intRenameMap;

    /** Floating point rename map. */
    RenameEntry *floatRenameMap;

    /** Free list interface. */
    SimpleFreeList *freeList;

    // Might want to make all these scoreboards into one large scoreboard.

    /** Scoreboard of physical integer registers, saying whether or not they
     *  are ready.
     */
    std::vector<bool> intScoreboard;
    
    /** Scoreboard of physical floating registers, saying whether or not they
     *  are ready.
     */
    std::vector<bool> floatScoreboard;

    /** Scoreboard of miscellaneous registers, saying whether or not they
     *  are ready.
     */
    std::vector<bool> miscScoreboard;
};

#endif //__CPU_O3_CPU_RENAME_MAP_HH__