1/* 2 * Copyright (c) 2012 Google 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: Gabe Black 29 */ 30 31#ifndef __ARCH_ARM_DECODER_HH__ 32#define __ARCH_ARM_DECODER_HH__ 33 34#include <cassert> 35 36#include "arch/arm/miscregs.hh" 37#include "arch/arm/types.hh"
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38#include "arch/generic/decode_cache.hh" |
39#include "base/types.hh"
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39#include "cpu/decode_cache.hh"
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40#include "cpu/static_inst.hh" |
41 42class ThreadContext; 43 44namespace ArmISA 45{ 46 47class Decoder 48{ 49 protected: 50 ThreadContext * tc; 51 //The extended machine instruction being generated 52 ExtMachInst emi; 53 MachInst data; 54 bool bigThumb; 55 bool instDone; 56 bool outOfBytes; 57 int offset; 58 bool foundIt; 59 ITSTATE itBits; 60 61 public: 62 void reset() 63 { 64 bigThumb = false; 65 offset = 0; 66 emi = 0; 67 instDone = false; 68 outOfBytes = true; 69 foundIt = false; 70 } 71 72 Decoder(ThreadContext * _tc) : tc(_tc), data(0) 73 { 74 reset(); 75 } 76 77 ThreadContext * getTC() 78 { 79 return tc; 80 } 81 82 void 83 setTC(ThreadContext * _tc) 84 { 85 tc = _tc; 86 } 87 88 void process(); 89 90 //Use this to give data to the decoder. This should be used 91 //when there is control flow. 92 void moreBytes(const PCState &pc, Addr fetchPC, MachInst inst); 93 94 //Use this to give data to the decoder. This should be used 95 //when instructions are executed in order. 96 void moreBytes(MachInst machInst) 97 { 98 moreBytes(0, 0, machInst); 99 } 100 101 inline void consumeBytes(int numBytes) 102 { 103 offset += numBytes; 104 assert(offset <= sizeof(MachInst)); 105 if (offset == sizeof(MachInst)) 106 outOfBytes = true; 107 } 108 109 bool needMoreBytes() const 110 { 111 return outOfBytes; 112 } 113 114 bool instReady() const 115 { 116 return instDone; 117 } 118 119 int getInstSize() const 120 { 121 return (!emi.thumb || emi.bigThumb) ? 4 : 2; 122 } 123 124 protected: 125 /// A cache of decoded instruction objects.
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125 static DecodeCache defaultCache;
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126 static GenericISA::BasicDecodeCache defaultCache; |
127 128 public: 129 StaticInstPtr decodeInst(ExtMachInst mach_inst); 130 131 /// Decode a machine instruction. 132 /// @param mach_inst The binary instruction to decode. 133 /// @retval A pointer to the corresponding StaticInst object. 134 StaticInstPtr 135 decode(ExtMachInst mach_inst, Addr addr) 136 { 137 return defaultCache.decode(this, mach_inst, addr); 138 } 139 140 StaticInstPtr 141 decode(ArmISA::PCState &nextPC) 142 { 143 if (!instDone) 144 return NULL; 145 146 assert(instDone); 147 ExtMachInst thisEmi = emi; 148 nextPC.npc(nextPC.pc() + getInstSize()); 149 if (foundIt) 150 nextPC.nextItstate(itBits); 151 thisEmi.itstate = nextPC.itstate(); 152 nextPC.size(getInstSize()); 153 emi = 0; 154 instDone = false; 155 foundIt = false; 156 return decode(thisEmi, nextPC.instAddr()); 157 } 158}; 159 160} // namespace ArmISA 161 162#endif // __ARCH_ARM_DECODER_HH__
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