rename_map.cc revision 2665
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 * Authors: Kevin Lim 29 */ 30 31#include <vector> 32 33#include "cpu/o3/rename_map.hh" 34 35using namespace std; 36 37// Todo: Consider making functions inline. Avoid having things that are 38// using the zero register or misc registers from adding on the registers 39// to the free list. Possibly remove the direct communication between 40// this and the freelist. Considering making inline bool functions that 41// determine if the register is a logical int, logical fp, physical int, 42// physical fp, etc. 43 44SimpleRenameMap::SimpleRenameMap(unsigned _numLogicalIntRegs, 45 unsigned _numPhysicalIntRegs, 46 unsigned _numLogicalFloatRegs, 47 unsigned _numPhysicalFloatRegs, 48 unsigned _numMiscRegs, 49 RegIndex _intZeroReg, 50 RegIndex _floatZeroReg) 51 : numLogicalIntRegs(_numLogicalIntRegs), 52 numPhysicalIntRegs(_numPhysicalIntRegs), 53 numLogicalFloatRegs(_numLogicalFloatRegs), 54 numPhysicalFloatRegs(_numPhysicalFloatRegs), 55 numMiscRegs(_numMiscRegs), 56 intZeroReg(_intZeroReg), 57 floatZeroReg(_floatZeroReg) 58{ 59 DPRINTF(Rename, "Rename: Creating rename map. Phys: %i / %i, Float: " 60 "%i / %i.\n", numLogicalIntRegs, numPhysicalIntRegs, 61 numLogicalFloatRegs, numPhysicalFloatRegs); 62 63 numLogicalRegs = numLogicalIntRegs + numLogicalFloatRegs; 64 65 numPhysicalRegs = numPhysicalIntRegs + numPhysicalFloatRegs; 66 67 //Create the rename maps, and their scoreboards. 68 intRenameMap = new RenameEntry[numLogicalIntRegs]; 69 floatRenameMap = new RenameEntry[numLogicalRegs]; 70 71 // Should combine this into one scoreboard. 72 intScoreboard.resize(numPhysicalIntRegs); 73 floatScoreboard.resize(numPhysicalRegs); 74 miscScoreboard.resize(numPhysicalRegs + numMiscRegs); 75 76 // Initialize the entries in the integer rename map to point to the 77 // physical registers of the same index, and consider each register 78 // ready until the first rename occurs. 79 for (RegIndex index = 0; index < numLogicalIntRegs; ++index) 80 { 81 intRenameMap[index].physical_reg = index; 82 intScoreboard[index] = 1; 83 } 84 85 // Initialize the rest of the physical registers (the ones that don't 86 // directly map to a logical register) as unready. 87 for (PhysRegIndex index = numLogicalIntRegs; 88 index < numPhysicalIntRegs; 89 ++index) 90 { 91 intScoreboard[index] = 0; 92 } 93 94 int float_reg_idx = numPhysicalIntRegs; 95 96 // Initialize the entries in the floating point rename map to point to 97 // the physical registers of the same index, and consider each register 98 // ready until the first rename occurs. 99 // Although the index refers purely to architected registers, because 100 // the floating reg indices come after the integer reg indices, they 101 // may exceed the size of a normal RegIndex (short). 102 for (PhysRegIndex index = numLogicalIntRegs; 103 index < numLogicalRegs; ++index) 104 { 105 floatRenameMap[index].physical_reg = float_reg_idx++; 106 } 107 108 for (PhysRegIndex index = numPhysicalIntRegs; 109 index < numPhysicalIntRegs + numLogicalFloatRegs; ++index) 110 { 111 floatScoreboard[index] = 1; 112 } 113 114 // Initialize the rest of the physical registers (the ones that don't 115 // directly map to a logical register) as unready. 116 for (PhysRegIndex index = numPhysicalIntRegs + numLogicalFloatRegs; 117 index < numPhysicalRegs; 118 ++index) 119 { 120 floatScoreboard[index] = 0; 121 } 122 123 // Initialize the entries in the misc register scoreboard to be ready. 124 for (PhysRegIndex index = numPhysicalRegs; 125 index < numPhysicalRegs + numMiscRegs; ++index) 126 { 127 miscScoreboard[index] = 1; 128 } 129} 130 131SimpleRenameMap::~SimpleRenameMap() 132{ 133 // Delete the rename maps as they were allocated with new. 134 delete [] intRenameMap; 135 delete [] floatRenameMap; 136} 137 138void 139SimpleRenameMap::setFreeList(SimpleFreeList *fl_ptr) 140{ 141 //Setup the interface to the freelist. 142 freeList = fl_ptr; 143} 144 145 146// Don't allow this stage to fault; force that check to the rename stage. 147// Simply ask to rename a logical register and get back a new physical 148// register index. 149SimpleRenameMap::RenameInfo 150SimpleRenameMap::rename(RegIndex arch_reg) 151{ 152 PhysRegIndex renamed_reg; 153 PhysRegIndex prev_reg; 154 155 if (arch_reg < numLogicalIntRegs) { 156 157 // Record the current physical register that is renamed to the 158 // requested architected register. 159 prev_reg = intRenameMap[arch_reg].physical_reg; 160 161 // If it's not referencing the zero register, then mark the register 162 // as not ready. 163 if (arch_reg != intZeroReg) { 164 // Get a free physical register to rename to. 165 renamed_reg = freeList->getIntReg(); 166 167 // Update the integer rename map. 168 intRenameMap[arch_reg].physical_reg = renamed_reg; 169 170 assert(renamed_reg >= 0 && renamed_reg < numPhysicalIntRegs); 171 172 // Mark register as not ready. 173 intScoreboard[renamed_reg] = false; 174 } else { 175 // Otherwise return the zero register so nothing bad happens. 176 renamed_reg = intZeroReg; 177 } 178 } else if (arch_reg < numLogicalRegs) { 179 // Subtract off the base offset for floating point registers. 180// arch_reg = arch_reg - numLogicalIntRegs; 181 182 // Record the current physical register that is renamed to the 183 // requested architected register. 184 prev_reg = floatRenameMap[arch_reg].physical_reg; 185 186 // If it's not referencing the zero register, then mark the register 187 // as not ready. 188 if (arch_reg != floatZeroReg) { 189 // Get a free floating point register to rename to. 190 renamed_reg = freeList->getFloatReg(); 191 192 // Update the floating point rename map. 193 floatRenameMap[arch_reg].physical_reg = renamed_reg; 194 195 assert(renamed_reg < numPhysicalRegs && 196 renamed_reg >= numPhysicalIntRegs); 197 198 // Mark register as not ready. 199 floatScoreboard[renamed_reg] = false; 200 } else { 201 // Otherwise return the zero register so nothing bad happens. 202 renamed_reg = floatZeroReg; 203 } 204 } else { 205 // Subtract off the base offset for miscellaneous registers. 206 arch_reg = arch_reg - numLogicalRegs; 207 208 // No renaming happens to the misc. registers. They are simply the 209 // registers that come after all the physical registers; thus 210 // take the base architected register and add the physical registers 211 // to it. 212 renamed_reg = arch_reg + numPhysicalRegs; 213 214 // Set the previous register to the same register; mainly it must be 215 // known that the prev reg was outside the range of normal registers 216 // so the free list can avoid adding it. 217 prev_reg = renamed_reg; 218 219 assert(renamed_reg < numPhysicalRegs + numMiscRegs); 220 221 miscScoreboard[renamed_reg] = false; 222 } 223 224 return RenameInfo(renamed_reg, prev_reg); 225} 226 227//Perhaps give this a pair as a return value, of the physical register 228//and whether or not it's ready. 229PhysRegIndex 230SimpleRenameMap::lookup(RegIndex arch_reg) 231{ 232 if (arch_reg < numLogicalIntRegs) { 233 return intRenameMap[arch_reg].physical_reg; 234 } else if (arch_reg < numLogicalRegs) { 235 // Subtract off the base FP offset. 236// arch_reg = arch_reg - numLogicalIntRegs; 237 238 return floatRenameMap[arch_reg].physical_reg; 239 } else { 240 // Subtract off the misc registers offset. 241 arch_reg = arch_reg - numLogicalRegs; 242 243 // Misc. regs don't rename, so simply add the base arch reg to 244 // the number of physical registers. 245 return numPhysicalRegs + arch_reg; 246 } 247} 248 249bool 250SimpleRenameMap::isReady(PhysRegIndex phys_reg) 251{ 252 if (phys_reg < numPhysicalIntRegs) { 253 return intScoreboard[phys_reg]; 254 } else if (phys_reg < numPhysicalRegs) { 255 256 // Subtract off the base FP offset. 257// phys_reg = phys_reg - numPhysicalIntRegs; 258 259 return floatScoreboard[phys_reg]; 260 } else { 261 // Subtract off the misc registers offset. 262// phys_reg = phys_reg - numPhysicalRegs; 263 264 return miscScoreboard[phys_reg]; 265 } 266} 267 268// In this implementation the miscellaneous registers do not actually rename, 269// so this function does not allow you to try to change their mappings. 270void 271SimpleRenameMap::setEntry(RegIndex arch_reg, PhysRegIndex renamed_reg) 272{ 273 if (arch_reg < numLogicalIntRegs) { 274 DPRINTF(Rename, "Rename Map: Integer register %i being set to %i.\n", 275 (int)arch_reg, renamed_reg); 276 277 intRenameMap[arch_reg].physical_reg = renamed_reg; 278 } else { 279 assert(arch_reg < (numLogicalIntRegs + numLogicalFloatRegs)); 280 281 DPRINTF(Rename, "Rename Map: Float register %i being set to %i.\n", 282 (int)arch_reg - numLogicalIntRegs, renamed_reg); 283 284 floatRenameMap[arch_reg].physical_reg = renamed_reg; 285 } 286} 287 288void 289SimpleRenameMap::squash(vector<RegIndex> freed_regs, 290 vector<UnmapInfo> unmaps) 291{ 292 panic("Not sure this function should be called."); 293 294 // Not sure the rename map should be able to access the free list 295 // like this. 296 while (!freed_regs.empty()) { 297 RegIndex free_register = freed_regs.back(); 298 299 if (free_register < numPhysicalIntRegs) { 300 freeList->addIntReg(free_register); 301 } else { 302 // Subtract off the base FP dependence tag. 303 free_register = free_register - numPhysicalIntRegs; 304 freeList->addFloatReg(free_register); 305 } 306 307 freed_regs.pop_back(); 308 } 309 310 // Take unmap info and roll back the rename map. 311} 312 313void 314SimpleRenameMap::markAsReady(PhysRegIndex ready_reg) 315{ 316 DPRINTF(Rename, "Rename map: Marking register %i as ready.\n", 317 (int)ready_reg); 318 319 if (ready_reg < numPhysicalIntRegs) { 320 assert(ready_reg >= 0); 321 322 intScoreboard[ready_reg] = 1; 323 } else if (ready_reg < numPhysicalRegs) { 324 325 // Subtract off the base FP offset. 326// ready_reg = ready_reg - numPhysicalIntRegs; 327 328 floatScoreboard[ready_reg] = 1; 329 } else { 330 //Subtract off the misc registers offset. 331// ready_reg = ready_reg - numPhysicalRegs; 332 333 miscScoreboard[ready_reg] = 1; 334 } 335} 336 337int 338SimpleRenameMap::numFreeEntries() 339{ 340 int free_int_regs = freeList->numFreeIntRegs(); 341 int free_float_regs = freeList->numFreeFloatRegs(); 342 343 if (free_int_regs < free_float_regs) { 344 return free_int_regs; 345 } else { 346 return free_float_regs; 347 } 348} 349