src/cpu/o3/scoreboard.hh

   1 /*
   2  * Copyright (c) 2005-2006 The Regents of The University of Michigan
   3  * Copyright (c) 2013 Advanced Micro Devices, Inc.
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions are
   8  * met: redistributions of source code must retain the above copyright
   9  * notice, this list of conditions and the following disclaimer;
  10  * redistributions in binary form must reproduce the above copyright
  11  * notice, this list of conditions and the following disclaimer in the
  12  * documentation and/or other materials provided with the distribution;
  13  * neither the name of the copyright holders nor the names of its
  14  * contributors may be used to endorse or promote products derived from
  15  * this software without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  18  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  19  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  20  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  21  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  22  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  23  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  24  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  25  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  26  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  27  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  28  */
  29
  30 #ifndef __CPU_O3_SCOREBOARD_HH__
  31 #define __CPU_O3_SCOREBOARD_HH__
  32
  33 #include <iostream>
  34 #include <utility>
  35 #include <vector>
  36
  37 #include "base/trace.hh"
  38 #include "config/the_isa.hh"
  39 #include "cpu/o3/comm.hh"
  40 #include "debug/Scoreboard.hh"
  41
  42 /**
  43  * Implements a simple scoreboard to track which registers are
  44  * ready. This class operates on the unified physical register space,
  45  * because the different classes of registers do not need to be distinguished.
  46  * Registers being part of a fixed mapping are always considered ready.
  47  */
  48 class Scoreboard
  49 {
  50   private:
  51     /** The object name, for DPRINTF.  We have to declare this
  52      *  explicitly because Scoreboard is not a SimObject. */
  53     const std::string _name;
  54
  55     /** Scoreboard of physical integer registers, saying whether or not they
  56      *  are ready. */
  57     std::vector<bool> regScoreBoard;
  58
  59     /** The number of actual physical registers */
  60     unsigned M5_CLASS_VAR_USED numPhysRegs;
  61
  62   public:
  63     /** Constructs a scoreboard.
  64      *  @param _numPhysicalRegs Number of physical registers.
  65      *  @param _numMiscRegs Number of miscellaneous registers.
  66      */
  67     Scoreboard(const std::string &_my_name,
  68                unsigned _numPhysicalRegs);
  69
  70     /** Destructor. */
  71     ~Scoreboard() {}
  72
  73     /** Returns the name of the scoreboard. */
  74     std::string name() const { return _name; };
  75
  76     /** Checks if the register is ready. */
  77     bool getReg(PhysRegIdPtr phys_reg) const
  78     {
  79         assert(phys_reg->flatIndex() < numPhysRegs);
  80
  81         if (phys_reg->isFixedMapping()) {
  82             // Fixed mapping regs are always ready
  83             return true;
  84         }
  85
  86         bool ready = regScoreBoard[phys_reg->flatIndex()];
  87
  88         if (phys_reg->isZeroReg())
  89             assert(ready);
  90
  91         return ready;
  92     }
  93
  94     /** Sets the register as ready. */
  95     void setReg(PhysRegIdPtr phys_reg)
  96     {
  97         assert(phys_reg->flatIndex() < numPhysRegs);
  98
  99         if (phys_reg->isFixedMapping()) {
 100             // Fixed mapping regs are always ready, ignore attempts to change
 101             // that
 102             return;
 103         }
 104
 105         DPRINTF(Scoreboard, "Setting reg %i (%s) as ready\n",
 106                 phys_reg->index(), phys_reg->className());
 107
 108         regScoreBoard[phys_reg->flatIndex()] = true;
 109     }
 110
 111     /** Sets the register as not ready. */
 112     void unsetReg(PhysRegIdPtr phys_reg)
 113     {
 114         assert(phys_reg->flatIndex() < numPhysRegs);
 115
 116         if (phys_reg->isFixedMapping()) {
 117             // Fixed mapping regs are always ready, ignore attempts to
 118             // change that
 119             return;
 120         }
 121
 122         // zero reg should never be marked unready
 123         if (phys_reg->isZeroReg())
 124             return;
 125
 126         regScoreBoard[phys_reg->flatIndex()] = false;
 127     }
 128
 129 };
 130
 131 #endif