decode_cache.hh revision 8541
18541Sgblack@eecs.umich.edu/* 28541Sgblack@eecs.umich.edu * Copyright (c) 2011 Google 38541Sgblack@eecs.umich.edu * All rights reserved. 48541Sgblack@eecs.umich.edu * 58541Sgblack@eecs.umich.edu * Redistribution and use in source and binary forms, with or without 68541Sgblack@eecs.umich.edu * modification, are permitted provided that the following conditions are 78541Sgblack@eecs.umich.edu * met: redistributions of source code must retain the above copyright 88541Sgblack@eecs.umich.edu * notice, this list of conditions and the following disclaimer; 98541Sgblack@eecs.umich.edu * redistributions in binary form must reproduce the above copyright 108541Sgblack@eecs.umich.edu * notice, this list of conditions and the following disclaimer in the 118541Sgblack@eecs.umich.edu * documentation and/or other materials provided with the distribution; 128541Sgblack@eecs.umich.edu * neither the name of the copyright holders nor the names of its 138541Sgblack@eecs.umich.edu * contributors may be used to endorse or promote products derived from 148541Sgblack@eecs.umich.edu * this software without specific prior written permission. 158541Sgblack@eecs.umich.edu * 168541Sgblack@eecs.umich.edu * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 178541Sgblack@eecs.umich.edu * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 188541Sgblack@eecs.umich.edu * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 198541Sgblack@eecs.umich.edu * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 208541Sgblack@eecs.umich.edu * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 218541Sgblack@eecs.umich.edu * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 228541Sgblack@eecs.umich.edu * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 238541Sgblack@eecs.umich.edu * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 248541Sgblack@eecs.umich.edu * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 258541Sgblack@eecs.umich.edu * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 268541Sgblack@eecs.umich.edu * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 278541Sgblack@eecs.umich.edu * 288541Sgblack@eecs.umich.edu * Authors: Gabe Black 298541Sgblack@eecs.umich.edu */ 308541Sgblack@eecs.umich.edu 318541Sgblack@eecs.umich.edu#ifndef __CPU_DECODE_CACHE_HH__ 328541Sgblack@eecs.umich.edu#define __CPU_DECODE_CACHE_HH__ 338541Sgblack@eecs.umich.edu 348541Sgblack@eecs.umich.edu#include "arch/isa_traits.hh" 358541Sgblack@eecs.umich.edu#include "arch/types.hh" 368541Sgblack@eecs.umich.edu#include "base/hashmap.hh" 378541Sgblack@eecs.umich.edu#include "config/the_isa.hh" 388541Sgblack@eecs.umich.edu#include "cpu/static_inst.hh" 398541Sgblack@eecs.umich.edu 408541Sgblack@eecs.umich.edutypedef StaticInstPtr (*DecodeInstFunc)(TheISA::ExtMachInst); 418541Sgblack@eecs.umich.edu 428541Sgblack@eecs.umich.edutemplate <DecodeInstFunc decodeInstFunc> 438541Sgblack@eecs.umich.educlass DecodeCache 448541Sgblack@eecs.umich.edu{ 458541Sgblack@eecs.umich.edu private: 468541Sgblack@eecs.umich.edu typedef TheISA::ExtMachInst ExtMachInst; 478541Sgblack@eecs.umich.edu 488541Sgblack@eecs.umich.edu /// Hash of decoded instructions. 498541Sgblack@eecs.umich.edu typedef m5::hash_map<ExtMachInst, StaticInstPtr> InstMap; 508541Sgblack@eecs.umich.edu InstMap instMap; 518541Sgblack@eecs.umich.edu 528541Sgblack@eecs.umich.edu /// A table of instructions which are already been decoded, indexed by 538541Sgblack@eecs.umich.edu /// page offset. 548541Sgblack@eecs.umich.edu class DecodePage 558541Sgblack@eecs.umich.edu { 568541Sgblack@eecs.umich.edu protected: 578541Sgblack@eecs.umich.edu StaticInstPtr instructions[TheISA::PageBytes]; 588541Sgblack@eecs.umich.edu 598541Sgblack@eecs.umich.edu // A helper function to compute the index of an address in the table. 608541Sgblack@eecs.umich.edu Addr offset(Addr addr) { return addr & (TheISA::PageBytes - 1); } 618541Sgblack@eecs.umich.edu 628541Sgblack@eecs.umich.edu public: 638541Sgblack@eecs.umich.edu /// Decode the given instruction. First attempt to find it in the 648541Sgblack@eecs.umich.edu /// table, then in the generic decode cache, and finally call the 658541Sgblack@eecs.umich.edu /// actual decode function. 668541Sgblack@eecs.umich.edu /// 678541Sgblack@eecs.umich.edu /// @param mach_inst The predecoded instruction to decode. 688541Sgblack@eecs.umich.edu /// @param addr The address the instruction came from. 698541Sgblack@eecs.umich.edu /// @param cache A cache of already decoded instructions. 708541Sgblack@eecs.umich.edu /// @retval The decoded instruction object. 718541Sgblack@eecs.umich.edu StaticInstPtr 728541Sgblack@eecs.umich.edu decode(const ExtMachInst &mach_inst, Addr addr, InstMap &instMap) 738541Sgblack@eecs.umich.edu { 748541Sgblack@eecs.umich.edu StaticInstPtr si = instructions[offset(addr)]; 758541Sgblack@eecs.umich.edu if (si && (si->machInst == mach_inst)) { 768541Sgblack@eecs.umich.edu return si; 778541Sgblack@eecs.umich.edu } 788541Sgblack@eecs.umich.edu 798541Sgblack@eecs.umich.edu InstMap::iterator iter = instMap.find(mach_inst); 808541Sgblack@eecs.umich.edu if (iter != instMap.end()) { 818541Sgblack@eecs.umich.edu si = iter->second; 828541Sgblack@eecs.umich.edu } else { 838541Sgblack@eecs.umich.edu si = decodeInstFunc(mach_inst); 848541Sgblack@eecs.umich.edu instMap[mach_inst] = si; 858541Sgblack@eecs.umich.edu } 868541Sgblack@eecs.umich.edu 878541Sgblack@eecs.umich.edu instructions[offset(addr)] = si; 888541Sgblack@eecs.umich.edu return si; 898541Sgblack@eecs.umich.edu } 908541Sgblack@eecs.umich.edu }; 918541Sgblack@eecs.umich.edu 928541Sgblack@eecs.umich.edu /// A store of DecodePages. Basically a slightly smarter hash_map. 938541Sgblack@eecs.umich.edu class DecodePages 948541Sgblack@eecs.umich.edu { 958541Sgblack@eecs.umich.edu protected: 968541Sgblack@eecs.umich.edu typedef typename m5::hash_map<Addr, DecodePage *> PageMap; 978541Sgblack@eecs.umich.edu typedef typename PageMap::iterator PageIt; 988541Sgblack@eecs.umich.edu PageIt recent[2]; 998541Sgblack@eecs.umich.edu PageMap pageMap; 1008541Sgblack@eecs.umich.edu 1018541Sgblack@eecs.umich.edu /// Update the small cache of recent lookups. 1028541Sgblack@eecs.umich.edu /// @param recentest The most recent result; 1038541Sgblack@eecs.umich.edu void 1048541Sgblack@eecs.umich.edu update(PageIt recentest) 1058541Sgblack@eecs.umich.edu { 1068541Sgblack@eecs.umich.edu recent[1] = recent[0]; 1078541Sgblack@eecs.umich.edu recent[0] = recentest; 1088541Sgblack@eecs.umich.edu } 1098541Sgblack@eecs.umich.edu 1108541Sgblack@eecs.umich.edu public: 1118541Sgblack@eecs.umich.edu /// Constructor 1128541Sgblack@eecs.umich.edu DecodePages() 1138541Sgblack@eecs.umich.edu { 1148541Sgblack@eecs.umich.edu recent[0] = recent[1] = pageMap.end(); 1158541Sgblack@eecs.umich.edu } 1168541Sgblack@eecs.umich.edu 1178541Sgblack@eecs.umich.edu /// Attempt to find the DecodePage which goes with a particular 1188541Sgblack@eecs.umich.edu /// address. First check the small cache of recent results, then 1198541Sgblack@eecs.umich.edu /// actually look in the hash_map. 1208541Sgblack@eecs.umich.edu /// @param addr The address to look up. 1218541Sgblack@eecs.umich.edu DecodePage * 1228541Sgblack@eecs.umich.edu findPage(Addr addr) 1238541Sgblack@eecs.umich.edu { 1248541Sgblack@eecs.umich.edu Addr page_addr = addr & ~(TheISA::PageBytes - 1); 1258541Sgblack@eecs.umich.edu 1268541Sgblack@eecs.umich.edu // Check against recent lookups. 1278541Sgblack@eecs.umich.edu if (recent[0] != pageMap.end()) { 1288541Sgblack@eecs.umich.edu if (recent[0]->first == page_addr) 1298541Sgblack@eecs.umich.edu return recent[0]->second; 1308541Sgblack@eecs.umich.edu if (recent[1] != pageMap.end() && 1318541Sgblack@eecs.umich.edu recent[1]->first == page_addr) { 1328541Sgblack@eecs.umich.edu update(recent[1]); 1338541Sgblack@eecs.umich.edu // recent[1] has just become recent[0]. 1348541Sgblack@eecs.umich.edu return recent[0]->second; 1358541Sgblack@eecs.umich.edu } 1368541Sgblack@eecs.umich.edu } 1378541Sgblack@eecs.umich.edu 1388541Sgblack@eecs.umich.edu // Actually look in the has_map. 1398541Sgblack@eecs.umich.edu PageIt it = pageMap.find(page_addr); 1408541Sgblack@eecs.umich.edu if (it != pageMap.end()) { 1418541Sgblack@eecs.umich.edu update(it); 1428541Sgblack@eecs.umich.edu return it->second; 1438541Sgblack@eecs.umich.edu } 1448541Sgblack@eecs.umich.edu 1458541Sgblack@eecs.umich.edu // Didn't find it so return NULL. 1468541Sgblack@eecs.umich.edu return NULL; 1478541Sgblack@eecs.umich.edu } 1488541Sgblack@eecs.umich.edu 1498541Sgblack@eecs.umich.edu void 1508541Sgblack@eecs.umich.edu addPage(Addr addr, DecodePage *page) 1518541Sgblack@eecs.umich.edu { 1528541Sgblack@eecs.umich.edu Addr page_addr = addr & ~(TheISA::PageBytes - 1); 1538541Sgblack@eecs.umich.edu typename PageMap::value_type to_insert(page_addr, page); 1548541Sgblack@eecs.umich.edu update(pageMap.insert(to_insert).first); 1558541Sgblack@eecs.umich.edu } 1568541Sgblack@eecs.umich.edu } decodePages; 1578541Sgblack@eecs.umich.edu 1588541Sgblack@eecs.umich.edu public: 1598541Sgblack@eecs.umich.edu /// Decode a machine instruction. 1608541Sgblack@eecs.umich.edu /// @param mach_inst The binary instruction to decode. 1618541Sgblack@eecs.umich.edu /// @retval A pointer to the corresponding StaticInst object. 1628541Sgblack@eecs.umich.edu StaticInstPtr 1638541Sgblack@eecs.umich.edu decode(ExtMachInst mach_inst, Addr addr) 1648541Sgblack@eecs.umich.edu { 1658541Sgblack@eecs.umich.edu // Try to find a matching address based table of instructions. 1668541Sgblack@eecs.umich.edu DecodePage *page = decodePages.findPage(addr); 1678541Sgblack@eecs.umich.edu if (!page) { 1688541Sgblack@eecs.umich.edu // Nothing was found, so create a new one. 1698541Sgblack@eecs.umich.edu page = new DecodePage; 1708541Sgblack@eecs.umich.edu decodePages.addPage(addr, page); 1718541Sgblack@eecs.umich.edu } 1728541Sgblack@eecs.umich.edu 1738541Sgblack@eecs.umich.edu // Use the table to decode the instruction. It will fall back to other 1748541Sgblack@eecs.umich.edu // mechanisms if it needs to. 1758541Sgblack@eecs.umich.edu return page->decode(mach_inst, addr, instMap); 1768541Sgblack@eecs.umich.edu } 1778541Sgblack@eecs.umich.edu}; 1788541Sgblack@eecs.umich.edu 1798541Sgblack@eecs.umich.edu#endif // __CPU_DECODE_CACHE_HH__ 180