cpu/o3/free_list.hh

   1 /*
   2  * Copyright (c) 2004-2005 The Regents of The University of Michigan
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions are
   7  * met: redistributions of source code must retain the above copyright
   8  * notice, this list of conditions and the following disclaimer;
   9  * redistributions in binary form must reproduce the above copyright
  10  * notice, this list of conditions and the following disclaimer in the
  11  * documentation and/or other materials provided with the distribution;
  12  * neither the name of the copyright holders nor the names of its
  13  * contributors may be used to endorse or promote products derived from
  14  * this software without specific prior written permission.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  17  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  18  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  19  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  20  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  21  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  22  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  26  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27  */
  28
  29 #ifndef __CPU_O3_CPU_FREE_LIST_HH__
  30 #define __CPU_O3_CPU_FREE_LIST_HH__
  31
  32 #include <iostream>
  33 #include <queue>
  34
  35 #include "arch/isa_traits.hh"
  36 #include "base/trace.hh"
  37 #include "base/traceflags.hh"
  38 #include "cpu/o3/comm.hh"
  39
  40 /**
  41  * FreeList class that simply holds the list of free integer and floating
  42  * point registers.  Can request for a free register of either type, and
  43  * also send back free registers of either type.  This is a very simple
  44  * class, but it should be sufficient for most implementations.  Like all
  45  * other classes, it assumes that the indices for the floating point
  46  * registers starts after the integer registers end.  Hence the variable
  47  * numPhysicalIntRegs is logically equivalent to the baseFP dependency.
  48  * Note that
  49  * while this most likely should be called FreeList, the name "FreeList"
  50  * is used in a typedef within the CPU Policy, and therefore no class
  51  * can be named simply "FreeList".
  52  * @todo: Give a better name to the base FP dependency.
  53  */
  54 class SimpleFreeList
  55 {
  56   private:
  57     /** The list of free integer registers. */
  58     std::queue<PhysRegIndex> freeIntRegs;
  59
  60     /** The list of free floating point registers. */
  61     std::queue<PhysRegIndex> freeFloatRegs;
  62
  63     /** Number of logical integer registers. */
  64     int numLogicalIntRegs;
  65
  66     /** Number of physical integer registers. */
  67     int numPhysicalIntRegs;
  68
  69     /** Number of logical floating point registers. */
  70     int numLogicalFloatRegs;
  71
  72     /** Number of physical floating point registers. */
  73     int numPhysicalFloatRegs;
  74
  75     /** Total number of physical registers. */
  76     int numPhysicalRegs;
  77
  78     /** DEBUG stuff below. */
  79     std::vector<int> freeIntRegsScoreboard;
  80
  81     std::vector<bool> freeFloatRegsScoreboard;
  82
  83   public:
  84     SimpleFreeList(unsigned _numLogicalIntRegs,
  85                    unsigned _numPhysicalIntRegs,
  86                    unsigned _numLogicalFloatRegs,
  87                    unsigned _numPhysicalFloatRegs);
  88
  89     inline PhysRegIndex getIntReg();
  90
  91     inline PhysRegIndex getFloatReg();
  92
  93     inline void addReg(PhysRegIndex freed_reg);
  94
  95     inline void addIntReg(PhysRegIndex freed_reg);
  96
  97     inline void addFloatReg(PhysRegIndex freed_reg);
  98
  99     bool hasFreeIntRegs()
 100     { return !freeIntRegs.empty(); }
 101
 102     bool hasFreeFloatRegs()
 103     { return !freeFloatRegs.empty(); }
 104
 105     int numFreeIntRegs()
 106     { return freeIntRegs.size(); }
 107
 108     int numFreeFloatRegs()
 109     { return freeFloatRegs.size(); }
 110 };
 111
 112 inline PhysRegIndex
 113 SimpleFreeList::getIntReg()
 114 {
 115     DPRINTF(Rename, "FreeList: Trying to get free integer register.\n");
 116     if (freeIntRegs.empty()) {
 117         panic("No free integer registers!");
 118     }
 119
 120     PhysRegIndex free_reg = freeIntRegs.front();
 121
 122     freeIntRegs.pop();
 123
 124     // DEBUG
 125     assert(freeIntRegsScoreboard[free_reg]);
 126     freeIntRegsScoreboard[free_reg] = 0;
 127
 128     return(free_reg);
 129 }
 130
 131 inline PhysRegIndex
 132 SimpleFreeList::getFloatReg()
 133 {
 134     DPRINTF(Rename, "FreeList: Trying to get free float register.\n");
 135     if (freeFloatRegs.empty()) {
 136         panic("No free integer registers!");
 137     }
 138
 139     PhysRegIndex free_reg = freeFloatRegs.front();
 140
 141     freeFloatRegs.pop();
 142
 143     // DEBUG
 144     assert(freeFloatRegsScoreboard[free_reg]);
 145     freeFloatRegsScoreboard[free_reg] = 0;
 146
 147     return(free_reg);
 148 }
 149
 150 inline void
 151 SimpleFreeList::addReg(PhysRegIndex freed_reg)
 152 {
 153     DPRINTF(Rename, "Freelist: Freeing register %i.\n", freed_reg);
 154     //Might want to add in a check for whether or not this register is
 155     //already in there.  A bit vector or something similar would be useful.
 156     if (freed_reg < numPhysicalIntRegs) {
 157         freeIntRegs.push(freed_reg);
 158
 159         // DEBUG
 160         assert(freeIntRegsScoreboard[freed_reg] == false);
 161         freeIntRegsScoreboard[freed_reg] = 1;
 162     } else if (freed_reg < numPhysicalRegs) {
 163         freeFloatRegs.push(freed_reg);
 164
 165         // DEBUG
 166         assert(freeFloatRegsScoreboard[freed_reg] == false);
 167         freeFloatRegsScoreboard[freed_reg] = 1;
 168     }
 169 }
 170
 171 inline void
 172 SimpleFreeList::addIntReg(PhysRegIndex freed_reg)
 173 {
 174     DPRINTF(Rename, "Freelist: Freeing int register %i.\n", freed_reg);
 175
 176     // DEBUG
 177     assert(!freeIntRegsScoreboard[freed_reg]);
 178     freeIntRegsScoreboard[freed_reg] = 1;
 179
 180     freeIntRegs.push(freed_reg);
 181 }
 182
 183 inline void
 184 SimpleFreeList::addFloatReg(PhysRegIndex freed_reg)
 185 {
 186     DPRINTF(Rename, "Freelist: Freeing float register %i.\n", freed_reg);
 187
 188     // DEBUG
 189     assert(!freeFloatRegsScoreboard[freed_reg]);
 190     freeFloatRegsScoreboard[freed_reg] = 1;
 191
 192     freeFloatRegs.push(freed_reg);
 193 }
 194
 195 #endif // __CPU_O3_CPU_FREE_LIST_HH__