free_list.hh revision 2292
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_FREE_LIST_HH__ 30#define __CPU_O3_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 while this most likely should be called FreeList, the name 49 * "FreeList" is used in a typedef within the CPU Policy, and therefore no 50 * class can be named simply "FreeList". 51 * @todo: Give a better name to the base FP dependency. 52 */ 53class SimpleFreeList 54{ 55 private: 56 /** The list of free integer registers. */ 57 std::queue<PhysRegIndex> freeIntRegs; 58 59 /** The list of free floating point registers. */ 60 std::queue<PhysRegIndex> freeFloatRegs; 61 62 /** Number of logical integer registers. */ 63 int numLogicalIntRegs; 64 65 /** Number of physical integer registers. */ 66 int numPhysicalIntRegs; 67 68 /** Number of logical floating point registers. */ 69 int numLogicalFloatRegs; 70 71 /** Number of physical floating point registers. */ 72 int numPhysicalFloatRegs; 73 74 /** Total number of physical registers. */ 75 int numPhysicalRegs; 76 77 public: 78 /** Constructs a free list. 79 * @param activeThreads Number of active threads. 80 * @param _numLogicalIntRegs Number of logical integer registers. 81 * @param _numPhysicalIntRegs Number of physical integer registers. 82 * @param _numLogicalFloatRegs Number of logical fp registers. 83 * @param _numPhysicalFloatRegs Number of physical fp registers. 84 */ 85 SimpleFreeList(unsigned activeThreads, 86 unsigned _numLogicalIntRegs, 87 unsigned _numPhysicalIntRegs, 88 unsigned _numLogicalFloatRegs, 89 unsigned _numPhysicalFloatRegs); 90 91 /** Gives the name of the freelist. */ 92 std::string name() const; 93 94 /** Gets a free integer register. */ 95 inline PhysRegIndex getIntReg(); 96 97 /** Gets a free fp register. */ 98 inline PhysRegIndex getFloatReg(); 99 100 /** Adds a register back to the free list. */ 101 inline void addReg(PhysRegIndex freed_reg); 102 103 /** Adds an integer register back to the free list. */ 104 inline void addIntReg(PhysRegIndex freed_reg); 105 106 /** Adds a fp register back to the free list. */ 107 inline void addFloatReg(PhysRegIndex freed_reg); 108 109 /** Checks if there are any free integer registers. */ 110 bool hasFreeIntRegs() 111 { return !freeIntRegs.empty(); } 112 113 /** Checks if there are any free fp registers. */ 114 bool hasFreeFloatRegs() 115 { return !freeFloatRegs.empty(); } 116 117 /** Returns the number of free integer registers. */ 118 int numFreeIntRegs() 119 { return freeIntRegs.size(); } 120 121 /** Returns the number of free fp registers. */ 122 int numFreeFloatRegs() 123 { return freeFloatRegs.size(); } 124}; 125 126inline PhysRegIndex 127SimpleFreeList::getIntReg() 128{ 129 DPRINTF(FreeList, "Trying to get free integer register.\n"); 130 131 if (freeIntRegs.empty()) { 132 panic("No free integer registers!"); 133 } 134 135 PhysRegIndex free_reg = freeIntRegs.front(); 136 137 freeIntRegs.pop(); 138 139 return(free_reg); 140} 141 142inline PhysRegIndex 143SimpleFreeList::getFloatReg() 144{ 145 DPRINTF(FreeList, "Trying to get free float register.\n"); 146 147 if (freeFloatRegs.empty()) { 148 panic("No free integer registers!"); 149 } 150 151 PhysRegIndex free_reg = freeFloatRegs.front(); 152 153 freeFloatRegs.pop(); 154 155 return(free_reg); 156} 157 158inline void 159SimpleFreeList::addReg(PhysRegIndex freed_reg) 160{ 161 DPRINTF(FreeList,"Freeing register %i.\n", freed_reg); 162 //Might want to add in a check for whether or not this register is 163 //already in there. A bit vector or something similar would be useful. 164 if (freed_reg < numPhysicalIntRegs) { 165 if (freed_reg != TheISA::ZeroReg) 166 freeIntRegs.push(freed_reg); 167 } else if (freed_reg < numPhysicalRegs) { 168 if (freed_reg != (TheISA::ZeroReg + numPhysicalIntRegs)) 169 freeFloatRegs.push(freed_reg); 170 } 171} 172 173inline void 174SimpleFreeList::addIntReg(PhysRegIndex freed_reg) 175{ 176 DPRINTF(FreeList,"Freeing int register %i.\n", freed_reg); 177 178 freeIntRegs.push(freed_reg); 179} 180 181inline void 182SimpleFreeList::addFloatReg(PhysRegIndex freed_reg) 183{ 184 DPRINTF(FreeList,"Freeing float register %i.\n", freed_reg); 185 186 freeFloatRegs.push(freed_reg); 187} 188 189#endif // __CPU_O3_FREE_LIST_HH__ 190