scoreboard.cc revision 12104:edd63f9c6184
1/* 2 * Copyright (c) 2013-2014 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(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.regClass) 60 { 61 case IntRegClass: 62 scoreboard_index = reg.regIdx; 63 ret = true; 64 break; 65 case FloatRegClass: 66 scoreboard_index = TheISA::NumIntRegs + TheISA::NumCCRegs + 67 reg.regIdx; 68 ret = true; 69 break; 70 case CCRegClass: 71 scoreboard_index = TheISA::NumIntRegs + reg.regIdx; 72 ret = true; 73 break; 74 case MiscRegClass: 75 /* Don't bother with Misc registers */ 76 ret = false; 77 break; 78 } 79 } 80 81 return ret; 82} 83 84/** Flatten a RegId, irrespective of what reg type it's pointing to */ 85static RegId 86flattenRegIndex(RegId reg, ThreadContext *thread_context) 87{ 88 switch (reg.regClass) 89 { 90 case IntRegClass: 91 reg.regIdx = thread_context->flattenIntIndex(reg.regIdx); 92 break; 93 case FloatRegClass: 94 reg.regIdx = thread_context->flattenFloatIndex(reg.regIdx); 95 break; 96 case CCRegClass: 97 reg.regIdx = thread_context->flattenCCIndex(reg.regIdx); 98 break; 99 case MiscRegClass: 100 /* Don't bother to flatten misc regs as we don't need them here */ 101 /* return thread_context->flattenMiscIndex(reg); */ 102 break; 103 } 104 105 return reg; 106} 107 108void 109Scoreboard::markupInstDests(MinorDynInstPtr inst, Cycles retire_time, 110 ThreadContext *thread_context, bool mark_unpredictable) 111{ 112 if (inst->isFault()) 113 return; 114 115 StaticInstPtr staticInst = inst->staticInst; 116 unsigned int num_dests = staticInst->numDestRegs(); 117 118 /** Mark each destination register */ 119 for (unsigned int dest_index = 0; dest_index < num_dests; 120 dest_index++) 121 { 122 RegId reg = flattenRegIndex( 123 staticInst->destRegIdx(dest_index), thread_context); 124 Index index; 125 126 if (findIndex(reg, index)) { 127 if (mark_unpredictable) 128 numUnpredictableResults[index]++; 129 130 inst->flatDestRegIdx[dest_index] = reg; 131 132 numResults[index]++; 133 returnCycle[index] = retire_time; 134 /* We should be able to rely on only being given accending 135 * execSeqNums, but sanity check */ 136 if (inst->id.execSeqNum > writingInst[index]) { 137 writingInst[index] = inst->id.execSeqNum; 138 fuIndices[index] = inst->fuIndex; 139 } 140 141 DPRINTF(MinorScoreboard, "Marking up inst: %s" 142 " regIndex: %d final numResults: %d returnCycle: %d\n", 143 *inst, index, numResults[index], returnCycle[index]); 144 } else { 145 /* Use ZeroReg to mark invalid/untracked dests */ 146 inst->flatDestRegIdx[dest_index] = RegId::zeroReg; 147 } 148 } 149} 150 151InstSeqNum 152Scoreboard::execSeqNumToWaitFor(MinorDynInstPtr inst, 153 ThreadContext *thread_context) 154{ 155 InstSeqNum ret = 0; 156 157 if (inst->isFault()) 158 return ret; 159 160 StaticInstPtr staticInst = inst->staticInst; 161 unsigned int num_srcs = staticInst->numSrcRegs(); 162 163 for (unsigned int src_index = 0; src_index < num_srcs; src_index++) { 164 RegId reg = flattenRegIndex(staticInst->srcRegIdx(src_index), 165 thread_context); 166 unsigned short int index; 167 168 if (findIndex(reg, index)) { 169 if (writingInst[index] > ret) 170 ret = writingInst[index]; 171 } 172 } 173 174 DPRINTF(MinorScoreboard, "Inst: %s depends on execSeqNum: %d\n", 175 *inst, ret); 176 177 return ret; 178} 179 180void 181Scoreboard::clearInstDests(MinorDynInstPtr inst, bool clear_unpredictable) 182{ 183 if (inst->isFault()) 184 return; 185 186 StaticInstPtr staticInst = inst->staticInst; 187 unsigned int num_dests = staticInst->numDestRegs(); 188 189 /** Mark each destination register */ 190 for (unsigned int dest_index = 0; dest_index < num_dests; 191 dest_index++) 192 { 193 RegId reg = inst->flatDestRegIdx[dest_index]; 194 Index index; 195 196 if (findIndex(reg, index)) { 197 if (clear_unpredictable && numUnpredictableResults[index] != 0) 198 numUnpredictableResults[index] --; 199 200 numResults[index] --; 201 202 if (numResults[index] == 0) { 203 returnCycle[index] = Cycles(0); 204 writingInst[index] = 0; 205 fuIndices[index] = -1; 206 } 207 208 DPRINTF(MinorScoreboard, "Clearing inst: %s" 209 " regIndex: %d final numResults: %d\n", 210 *inst, index, numResults[index]); 211 } 212 } 213} 214 215bool 216Scoreboard::canInstIssue(MinorDynInstPtr inst, 217 const std::vector<Cycles> *src_reg_relative_latencies, 218 const std::vector<bool> *cant_forward_from_fu_indices, 219 Cycles now, ThreadContext *thread_context) 220{ 221 /* Always allow fault to be issued */ 222 if (inst->isFault()) 223 return true; 224 225 StaticInstPtr staticInst = inst->staticInst; 226 unsigned int num_srcs = staticInst->numSrcRegs(); 227 228 /* Default to saying you can issue */ 229 bool ret = true; 230 231 unsigned int num_relative_latencies = 0; 232 Cycles default_relative_latency = Cycles(0); 233 234 /* Where relative latencies are given, the default is the last 235 * one as that allows the rel. lat. list to be shorted than the 236 * number of src. regs */ 237 if (src_reg_relative_latencies && 238 src_reg_relative_latencies->size() != 0) 239 { 240 num_relative_latencies = src_reg_relative_latencies->size(); 241 default_relative_latency = (*src_reg_relative_latencies) 242 [num_relative_latencies-1]; 243 } 244 245 /* For each source register, find the latest result */ 246 unsigned int src_index = 0; 247 while (src_index < num_srcs && /* More registers */ 248 ret /* Still possible */) 249 { 250 RegId reg = flattenRegIndex(staticInst->srcRegIdx(src_index), 251 thread_context); 252 unsigned short int index; 253 254 if (findIndex(reg, index)) { 255 bool cant_forward = fuIndices[index] != 1 && 256 cant_forward_from_fu_indices && 257 index < cant_forward_from_fu_indices->size() && 258 (*cant_forward_from_fu_indices)[index]; 259 260 Cycles relative_latency = (cant_forward ? Cycles(0) : 261 (src_index >= num_relative_latencies ? 262 default_relative_latency : 263 (*src_reg_relative_latencies)[src_index])); 264 265 if (returnCycle[index] > (now + relative_latency) || 266 numUnpredictableResults[index] != 0) 267 { 268 ret = false; 269 } 270 } 271 src_index++; 272 } 273 274 if (DTRACE(MinorTiming)) { 275 if (ret && num_srcs > num_relative_latencies && 276 num_relative_latencies != 0) 277 { 278 DPRINTF(MinorTiming, "Warning, inst: %s timing extra decode has" 279 " more src. regs: %d than relative latencies: %d\n", 280 staticInst->disassemble(0), num_srcs, num_relative_latencies); 281 } 282 } 283 284 return ret; 285} 286 287void 288Scoreboard::minorTrace() const 289{ 290 std::ostringstream result_stream; 291 292 bool printed_element = false; 293 294 unsigned int i = 0; 295 while (i < numRegs) { 296 unsigned short int num_results = numResults[i]; 297 unsigned short int num_unpredictable_results = 298 numUnpredictableResults[i]; 299 300 if (!(num_results == 0 && num_unpredictable_results == Cycles(0))) { 301 if (printed_element) 302 result_stream << ','; 303 304 result_stream << '(' << i << ',' 305 << num_results << '/' 306 << num_unpredictable_results << '/' 307 << returnCycle[i] << '/' 308 << writingInst[i] << ')'; 309 310 printed_element = true; 311 } 312 313 i++; 314 } 315 316 MINORTRACE("busy=%s\n", result_stream.str()); 317} 318 319} 320