free_list.hh revision 2669
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/misc.hh" 37#include "base/trace.hh" 38#include "base/traceflags.hh" 39#include "cpu/o3/comm.hh" 40 41/** 42 * FreeList class that simply holds the list of free integer and floating 43 * point registers. Can request for a free register of either type, and 44 * also send back free registers of either type. This is a very simple 45 * class, but it should be sufficient for most implementations. Like all 46 * other classes, it assumes that the indices for the floating point 47 * registers starts after the integer registers end. Hence the variable 48 * numPhysicalIntRegs is logically equivalent to the baseFP dependency. 49 * Note that while this most likely should be called FreeList, the name 50 * "FreeList" is used in a typedef within the CPU Policy, and therefore no 51 * class can be named simply "FreeList". 52 * @todo: Give a better name to the base FP dependency. 53 */ 54class 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 public: 79 /** Constructs a free list. 80 * @param activeThreads Number of active threads. 81 * @param _numLogicalIntRegs Number of logical integer registers. 82 * @param _numPhysicalIntRegs Number of physical integer registers. 83 * @param _numLogicalFloatRegs Number of logical fp registers. 84 * @param _numPhysicalFloatRegs Number of physical fp registers. 85 */ 86 SimpleFreeList(unsigned activeThreads, 87 unsigned _numLogicalIntRegs, 88 unsigned _numPhysicalIntRegs, 89 unsigned _numLogicalFloatRegs, 90 unsigned _numPhysicalFloatRegs); 91 92 /** Gives the name of the freelist. */ 93 std::string name() const; 94 95 /** Gets a free integer register. */ 96 inline PhysRegIndex getIntReg(); 97 98 /** Gets a free fp register. */ 99 inline PhysRegIndex getFloatReg(); 100 101 /** Adds a register back to the free list. */ 102 inline void addReg(PhysRegIndex freed_reg); 103 104 /** Adds an integer register back to the free list. */ 105 inline void addIntReg(PhysRegIndex freed_reg); 106 107 /** Adds a fp register back to the free list. */ 108 inline void addFloatReg(PhysRegIndex freed_reg); 109 110 /** Checks if there are any free integer registers. */ 111 bool hasFreeIntRegs() 112 { return !freeIntRegs.empty(); } 113 114 /** Checks if there are any free fp registers. */ 115 bool hasFreeFloatRegs() 116 { return !freeFloatRegs.empty(); } 117 118 /** Returns the number of free integer registers. */ 119 int numFreeIntRegs() 120 { return freeIntRegs.size(); } 121 122 /** Returns the number of free fp registers. */ 123 int numFreeFloatRegs() 124 { return freeFloatRegs.size(); } 125}; 126 127inline PhysRegIndex 128SimpleFreeList::getIntReg() 129{ 130 DPRINTF(FreeList, "Trying to get free integer register.\n"); 131 132 if (freeIntRegs.empty()) { 133 panic("No free integer registers!"); 134 } 135 136 PhysRegIndex free_reg = freeIntRegs.front(); 137 138 freeIntRegs.pop(); 139 140 return(free_reg); 141} 142 143inline PhysRegIndex 144SimpleFreeList::getFloatReg() 145{ 146 DPRINTF(FreeList, "Trying to get free float register.\n"); 147 148 if (freeFloatRegs.empty()) { 149 panic("No free integer registers!"); 150 } 151 152 PhysRegIndex free_reg = freeFloatRegs.front(); 153 154 freeFloatRegs.pop(); 155 156 return(free_reg); 157} 158 159inline void 160SimpleFreeList::addReg(PhysRegIndex freed_reg) 161{ 162 DPRINTF(FreeList,"Freeing register %i.\n", freed_reg); 163 //Might want to add in a check for whether or not this register is 164 //already in there. A bit vector or something similar would be useful. 165 if (freed_reg < numPhysicalIntRegs) { 166 if (freed_reg != TheISA::ZeroReg) 167 freeIntRegs.push(freed_reg); 168 } else if (freed_reg < numPhysicalRegs) { 169 if (freed_reg != (TheISA::ZeroReg + numPhysicalIntRegs)) 170 freeFloatRegs.push(freed_reg); 171 } 172} 173 174inline void 175SimpleFreeList::addIntReg(PhysRegIndex freed_reg) 176{ 177 DPRINTF(FreeList,"Freeing int register %i.\n", freed_reg); 178 179 freeIntRegs.push(freed_reg); 180} 181 182inline void 183SimpleFreeList::addFloatReg(PhysRegIndex freed_reg) 184{ 185 DPRINTF(FreeList,"Freeing float register %i.\n", freed_reg); 186 187 freeFloatRegs.push(freed_reg); 188} 189 190#endif // __CPU_O3_FREE_LIST_HH__ 191