scoreboard.cc revision 13597:6b0f8e9cdeb5
1/* 2 * Copyright (c) 2013-2014, 2016 ARM Limited 3 * All rights reserved 4 * 5 * The license below extends only to copyright in the software and shall 6 * not be construed as granting a license to any other intellectual 7 * property including but not limited to intellectual property relating 8 * to a hardware implementation of the functionality of the software 9 * licensed hereunder. You may use the software subject to the license 10 * terms below provided that you ensure that this notice is replicated 11 * unmodified and in its entirety in all distributions of the software, 12 * modified or unmodified, in source code or in binary form. 13 * 14 * Redistribution and use in source and binary forms, with or without 15 * modification, are permitted provided that the following conditions are 16 * met: redistributions of source code must retain the above copyright 17 * notice, this list of conditions and the following disclaimer; 18 * redistributions in binary form must reproduce the above copyright 19 * notice, this list of conditions and the following disclaimer in the 20 * documentation and/or other materials provided with the distribution; 21 * neither the name of the copyright holders nor the names of its 22 * contributors may be used to endorse or promote products derived from 23 * this software without specific prior written permission. 24 * 25 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 26 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 27 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 28 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 29 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 30 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 31 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 32 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 33 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 34 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 35 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 36 * 37 * Authors: Andrew Bardsley 38 */ 39 40#include "cpu/minor/scoreboard.hh" 41 42#include "arch/registers.hh" 43#include "cpu/reg_class.hh" 44#include "debug/MinorScoreboard.hh" 45#include "debug/MinorTiming.hh" 46 47namespace Minor 48{ 49 50bool 51Scoreboard::findIndex(const RegId& reg, Index &scoreboard_index) 52{ 53 bool ret = false; 54 55 if (reg.isZeroReg()) { 56 /* Don't bother with the zero register */ 57 ret = false; 58 } else { 59 switch (reg.classValue()) 60 { 61 case IntRegClass: 62 scoreboard_index = reg.index(); 63 ret = true; 64 break; 65 case FloatRegClass: 66 scoreboard_index = TheISA::NumIntRegs + TheISA::NumCCRegs + 67 reg.index(); 68 ret = true; 69 break; 70 case VecRegClass: 71 scoreboard_index = TheISA::NumIntRegs + TheISA::NumCCRegs + 72 TheISA::NumFloatRegs + reg.index(); 73 ret = true; 74 break; 75 case VecElemClass: 76 scoreboard_index = TheISA::NumIntRegs + TheISA::NumCCRegs + 77 TheISA::NumFloatRegs + reg.flatIndex(); 78 ret = true; 79 break; 80 case CCRegClass: 81 scoreboard_index = TheISA::NumIntRegs + reg.index(); 82 ret = true; 83 break; 84 case MiscRegClass: 85 /* Don't bother with Misc registers */ 86 ret = false; 87 break; 88 default: 89 panic("Unknown register class: %d", 90 static_cast<int>(reg.classValue())); 91 } 92 } 93 94 return ret; 95} 96 97/** Flatten a RegId, irrespective of what reg type it's pointing to */ 98static RegId 99flattenRegIndex(const RegId& reg, ThreadContext *thread_context) 100{ 101 return thread_context->flattenRegId(reg); 102} 103 104void 105Scoreboard::markupInstDests(MinorDynInstPtr inst, Cycles retire_time, 106 ThreadContext *thread_context, bool mark_unpredictable) 107{ 108 if (inst->isFault()) 109 return; 110 111 StaticInstPtr staticInst = inst->staticInst; 112 unsigned int num_dests = staticInst->numDestRegs(); 113 114 /** Mark each destination register */ 115 for (unsigned int dest_index = 0; dest_index < num_dests; 116 dest_index++) 117 { 118 RegId reg = flattenRegIndex( 119 staticInst->destRegIdx(dest_index), thread_context); 120 Index index; 121 122 if (findIndex(reg, index)) { 123 if (mark_unpredictable) 124 numUnpredictableResults[index]++; 125 126 inst->flatDestRegIdx[dest_index] = reg; 127 128 numResults[index]++; 129 returnCycle[index] = retire_time; 130 /* We should be able to rely on only being given accending 131 * execSeqNums, but sanity check */ 132 if (inst->id.execSeqNum > writingInst[index]) { 133 writingInst[index] = inst->id.execSeqNum; 134 fuIndices[index] = inst->fuIndex; 135 } 136 137 DPRINTF(MinorScoreboard, "Marking up inst: %s" 138 " regIndex: %d final numResults: %d returnCycle: %d\n", 139 *inst, index, numResults[index], returnCycle[index]); 140 } else { 141 /* Use ZeroReg to mark invalid/untracked dests */ 142 inst->flatDestRegIdx[dest_index] = RegId(IntRegClass, 143 TheISA::ZeroReg); 144 } 145 } 146} 147 148InstSeqNum 149Scoreboard::execSeqNumToWaitFor(MinorDynInstPtr inst, 150 ThreadContext *thread_context) 151{ 152 InstSeqNum ret = 0; 153 154 if (inst->isFault()) 155 return ret; 156 157 StaticInstPtr staticInst = inst->staticInst; 158 unsigned int num_srcs = staticInst->numSrcRegs(); 159 160 for (unsigned int src_index = 0; src_index < num_srcs; src_index++) { 161 RegId reg = flattenRegIndex(staticInst->srcRegIdx(src_index), 162 thread_context); 163 unsigned short int index; 164 165 if (findIndex(reg, index)) { 166 if (writingInst[index] > ret) 167 ret = writingInst[index]; 168 } 169 } 170 171 DPRINTF(MinorScoreboard, "Inst: %s depends on execSeqNum: %d\n", 172 *inst, ret); 173 174 return ret; 175} 176 177void 178Scoreboard::clearInstDests(MinorDynInstPtr inst, bool clear_unpredictable) 179{ 180 if (inst->isFault()) 181 return; 182 183 StaticInstPtr staticInst = inst->staticInst; 184 unsigned int num_dests = staticInst->numDestRegs(); 185 186 /** Mark each destination register */ 187 for (unsigned int dest_index = 0; dest_index < num_dests; 188 dest_index++) 189 { 190 const RegId& reg = inst->flatDestRegIdx[dest_index]; 191 Index index; 192 193 if (findIndex(reg, index)) { 194 if (clear_unpredictable && numUnpredictableResults[index] != 0) 195 numUnpredictableResults[index] --; 196 197 numResults[index] --; 198 199 if (numResults[index] == 0) { 200 returnCycle[index] = Cycles(0); 201 writingInst[index] = 0; 202 fuIndices[index] = -1; 203 } 204 205 DPRINTF(MinorScoreboard, "Clearing inst: %s" 206 " regIndex: %d final numResults: %d\n", 207 *inst, index, numResults[index]); 208 } 209 } 210} 211 212bool 213Scoreboard::canInstIssue(MinorDynInstPtr inst, 214 const std::vector<Cycles> *src_reg_relative_latencies, 215 const std::vector<bool> *cant_forward_from_fu_indices, 216 Cycles now, ThreadContext *thread_context) 217{ 218 /* Always allow fault to be issued */ 219 if (inst->isFault()) 220 return true; 221 222 StaticInstPtr staticInst = inst->staticInst; 223 unsigned int num_srcs = staticInst->numSrcRegs(); 224 225 /* Default to saying you can issue */ 226 bool ret = true; 227 228 unsigned int num_relative_latencies = 0; 229 Cycles default_relative_latency = Cycles(0); 230 231 /* Where relative latencies are given, the default is the last 232 * one as that allows the rel. lat. list to be shorted than the 233 * number of src. regs */ 234 if (src_reg_relative_latencies && 235 src_reg_relative_latencies->size() != 0) 236 { 237 num_relative_latencies = src_reg_relative_latencies->size(); 238 default_relative_latency = (*src_reg_relative_latencies) 239 [num_relative_latencies-1]; 240 } 241 242 /* For each source register, find the latest result */ 243 unsigned int src_index = 0; 244 while (src_index < num_srcs && /* More registers */ 245 ret /* Still possible */) 246 { 247 RegId reg = flattenRegIndex(staticInst->srcRegIdx(src_index), 248 thread_context); 249 unsigned short int index; 250 251 if (findIndex(reg, index)) { 252 bool cant_forward = fuIndices[index] != 1 && 253 cant_forward_from_fu_indices && 254 index < cant_forward_from_fu_indices->size() && 255 (*cant_forward_from_fu_indices)[index]; 256 257 Cycles relative_latency = (cant_forward ? Cycles(0) : 258 (src_index >= num_relative_latencies ? 259 default_relative_latency : 260 (*src_reg_relative_latencies)[src_index])); 261 262 if (returnCycle[index] > (now + relative_latency) || 263 numUnpredictableResults[index] != 0) 264 { 265 ret = false; 266 } 267 } 268 src_index++; 269 } 270 271 if (DTRACE(MinorTiming)) { 272 if (ret && num_srcs > num_relative_latencies && 273 num_relative_latencies != 0) 274 { 275 DPRINTF(MinorTiming, "Warning, inst: %s timing extra decode has" 276 " more src. regs: %d than relative latencies: %d\n", 277 staticInst->disassemble(0), num_srcs, num_relative_latencies); 278 } 279 } 280 281 return ret; 282} 283 284void 285Scoreboard::minorTrace() const 286{ 287 std::ostringstream result_stream; 288 289 bool printed_element = false; 290 291 unsigned int i = 0; 292 while (i < numRegs) { 293 unsigned short int num_results = numResults[i]; 294 unsigned short int num_unpredictable_results = 295 numUnpredictableResults[i]; 296 297 if (!(num_results == 0 && num_unpredictable_results == Cycles(0))) { 298 if (printed_element) 299 result_stream << ','; 300 301 result_stream << '(' << i << ',' 302 << num_results << '/' 303 << num_unpredictable_results << '/' 304 << returnCycle[i] << '/' 305 << writingInst[i] << ')'; 306 307 printed_element = true; 308 } 309 310 i++; 311 } 312 313 MINORTRACE("busy=%s\n", result_stream.str()); 314} 315 316} 317