store_set.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 "base/trace.hh" 32#include "cpu/o3/store_set.hh" 33 34StoreSet::StoreSet(int _SSIT_size, int _LFST_size) 35 : SSIT_size(_SSIT_size), LFST_size(_LFST_size) 36{ 37 DPRINTF(StoreSet, "StoreSet: Creating store set object.\n"); 38 DPRINTF(StoreSet, "StoreSet: SSIT size: %i, LFST size: %i.\n", 39 SSIT_size, LFST_size); 40 41 SSIT = new SSID[SSIT_size]; 42 43 validSSIT.resize(SSIT_size); 44 45 for (int i = 0; i < SSIT_size; ++i) 46 validSSIT[i] = false; 47 48 LFST = new InstSeqNum[LFST_size]; 49 50 validLFST.resize(LFST_size); 51 52 SSCounters = new int[LFST_size]; 53 54 for (int i = 0; i < LFST_size; ++i) 55 { 56 validLFST[i] = false; 57 SSCounters[i] = 0; 58 } 59 60 index_mask = SSIT_size - 1; 61 62 offset_bits = 2; 63} 64 65void 66StoreSet::violation(Addr store_PC, Addr load_PC) 67{ 68 int load_index = calcIndex(load_PC); 69 int store_index = calcIndex(store_PC); 70 71 assert(load_index < SSIT_size && store_index < SSIT_size); 72 73 bool valid_load_SSID = validSSIT[load_index]; 74 bool valid_store_SSID = validSSIT[store_index]; 75 76 if (!valid_load_SSID && !valid_store_SSID) { 77 // Calculate a new SSID here. 78 SSID new_set = calcSSID(load_PC); 79 80 validSSIT[load_index] = true; 81 82 SSIT[load_index] = new_set; 83 84 validSSIT[store_index] = true; 85 86 SSIT[store_index] = new_set; 87 88 assert(new_set < LFST_size); 89 90 SSCounters[new_set]++; 91 92 93 DPRINTF(StoreSet, "StoreSet: Neither load nor store had a valid " 94 "storeset, creating a new one: %i for load %#x, store %#x\n", 95 new_set, load_PC, store_PC); 96 } else if (valid_load_SSID && !valid_store_SSID) { 97 SSID load_SSID = SSIT[load_index]; 98 99 validSSIT[store_index] = true; 100 101 SSIT[store_index] = load_SSID; 102 103 assert(load_SSID < LFST_size); 104 105 SSCounters[load_SSID]++; 106 107 DPRINTF(StoreSet, "StoreSet: Load had a valid store set. Adding " 108 "store to that set: %i for load %#x, store %#x\n", 109 load_SSID, load_PC, store_PC); 110 } else if (!valid_load_SSID && valid_store_SSID) { 111 SSID store_SSID = SSIT[store_index]; 112 113 validSSIT[load_index] = true; 114 115 SSIT[load_index] = store_SSID; 116 117 // Because we are having a load point to an already existing set, 118 // the size of the store set is not incremented. 119 120 DPRINTF(StoreSet, "StoreSet: Store had a valid store set: %i for " 121 "load %#x, store %#x\n", 122 store_SSID, load_PC, store_PC); 123 } else { 124 SSID load_SSID = SSIT[load_index]; 125 SSID store_SSID = SSIT[store_index]; 126 127 assert(load_SSID < LFST_size && store_SSID < LFST_size); 128 129 int load_SS_size = SSCounters[load_SSID]; 130 int store_SS_size = SSCounters[store_SSID]; 131 132 // If the load has the bigger store set, then assign the store 133 // to the same store set as the load. Otherwise vice-versa. 134 if (load_SS_size > store_SS_size) { 135 SSIT[store_index] = load_SSID; 136 137 SSCounters[load_SSID]++; 138 SSCounters[store_SSID]--; 139 140 DPRINTF(StoreSet, "StoreSet: Load had bigger store set: %i; " 141 "for load %#x, store %#x\n", 142 load_SSID, load_PC, store_PC); 143 } else { 144 SSIT[load_index] = store_SSID; 145 146 SSCounters[store_SSID]++; 147 SSCounters[load_SSID]--; 148 149 DPRINTF(StoreSet, "StoreSet: Store had bigger store set: %i; " 150 "for load %#x, store %#x\n", 151 store_SSID, load_PC, store_PC); 152 } 153 } 154} 155 156void 157StoreSet::insertLoad(Addr load_PC, InstSeqNum load_seq_num) 158{ 159 // Does nothing. 160 return; 161} 162 163void 164StoreSet::insertStore(Addr store_PC, InstSeqNum store_seq_num) 165{ 166 int index = calcIndex(store_PC); 167 168 int store_SSID; 169 170 assert(index < SSIT_size); 171 172 if (!validSSIT[index]) { 173 // Do nothing if there's no valid entry. 174 return; 175 } else { 176 store_SSID = SSIT[index]; 177 178 assert(store_SSID < LFST_size); 179 180 // Update the last store that was fetched with the current one. 181 LFST[store_SSID] = store_seq_num; 182 183 validLFST[store_SSID] = 1; 184 185 DPRINTF(StoreSet, "Store %#x updated the LFST, SSID: %i\n", 186 store_PC, store_SSID); 187 } 188} 189 190InstSeqNum 191StoreSet::checkInst(Addr PC) 192{ 193 int index = calcIndex(PC); 194 195 int inst_SSID; 196 197 assert(index < SSIT_size); 198 199 if (!validSSIT[index]) { 200 DPRINTF(StoreSet, "Inst %#x with index %i had no SSID\n", 201 PC, index); 202 203 // Return 0 if there's no valid entry. 204 return 0; 205 } else { 206 inst_SSID = SSIT[index]; 207 208 assert(inst_SSID < LFST_size); 209 210 if (!validLFST[inst_SSID]) { 211 212 DPRINTF(StoreSet, "Inst %#x with index %i and SSID %i had no " 213 "dependency\n", PC, index, inst_SSID); 214 215 return 0; 216 } else { 217 DPRINTF(StoreSet, "Inst %#x with index %i and SSID %i had LFST " 218 "inum of %i\n", PC, index, inst_SSID, LFST[inst_SSID]); 219 220 return LFST[inst_SSID]; 221 } 222 } 223} 224 225void 226StoreSet::issued(Addr issued_PC, InstSeqNum issued_seq_num, bool is_store) 227{ 228 // This only is updated upon a store being issued. 229 if (!is_store) { 230 return; 231 } 232 233 int index = calcIndex(issued_PC); 234 235 int store_SSID; 236 237 assert(index < SSIT_size); 238 239 // Make sure the SSIT still has a valid entry for the issued store. 240 if (!validSSIT[index]) { 241 return; 242 } 243 244 store_SSID = SSIT[index]; 245 246 assert(store_SSID < LFST_size); 247 248 // If the last fetched store in the store set refers to the store that 249 // was just issued, then invalidate the entry. 250 if (validLFST[store_SSID] && LFST[store_SSID] == issued_seq_num) { 251 DPRINTF(StoreSet, "StoreSet: store invalidated itself in LFST.\n"); 252 validLFST[store_SSID] = false; 253 } 254} 255 256void 257StoreSet::squash(InstSeqNum squashed_num) 258{ 259 // Not really sure how to do this well. 260 // Generally this is small enough that it should be okay; short circuit 261 // evaluation should take care of invalid entries. 262 263 DPRINTF(StoreSet, "StoreSet: Squashing until inum %i\n", 264 squashed_num); 265 266 for (int i = 0; i < LFST_size; ++i) { 267 if (validLFST[i] && LFST[i] < squashed_num) { 268 validLFST[i] = false; 269 } 270 } 271} 272 273void 274StoreSet::clear() 275{ 276 for (int i = 0; i < SSIT_size; ++i) { 277 validSSIT[i] = false; 278 } 279 280 for (int i = 0; i < LFST_size; ++i) { 281 validLFST[i] = false; 282 } 283} 284 285