decoder.hh revision 9024:5851586f399c
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_MIPS_DECODER_HH__ 32#define __ARCH_MIPS_DECODER_HH__ 33 34#include "arch/generic/decode_cache.hh" 35#include "arch/mips/types.hh" 36#include "base/misc.hh" 37#include "base/types.hh" 38#include "cpu/static_inst.hh" 39 40class ThreadContext; 41 42namespace MipsISA 43{ 44 45class Decoder 46{ 47 protected: 48 ThreadContext * tc; 49 //The extended machine instruction being generated 50 ExtMachInst emi; 51 bool instDone; 52 53 public: 54 Decoder(ThreadContext * _tc) : tc(_tc), instDone(false) 55 {} 56 57 ThreadContext *getTC() 58 { 59 return tc; 60 } 61 62 void 63 setTC(ThreadContext *_tc) 64 { 65 tc = _tc; 66 } 67 68 void 69 process() 70 { 71 } 72 73 void 74 reset() 75 { 76 instDone = false; 77 } 78 79 //Use this to give data to the decoder. This should be used 80 //when there is control flow. 81 void 82 moreBytes(const PCState &pc, Addr fetchPC, MachInst inst) 83 { 84 emi = inst; 85 instDone = true; 86 } 87 88 bool 89 needMoreBytes() 90 { 91 return true; 92 } 93 94 bool 95 instReady() 96 { 97 return instDone; 98 } 99 100 protected: 101 /// A cache of decoded instruction objects. 102 static GenericISA::BasicDecodeCache defaultCache; 103 104 public: 105 StaticInstPtr decodeInst(ExtMachInst mach_inst); 106 107 /// Decode a machine instruction. 108 /// @param mach_inst The binary instruction to decode. 109 /// @retval A pointer to the corresponding StaticInst object. 110 StaticInstPtr 111 decode(ExtMachInst mach_inst, Addr addr) 112 { 113 return defaultCache.decode(this, mach_inst, addr); 114 } 115 116 StaticInstPtr 117 decode(MipsISA::PCState &nextPC) 118 { 119 if (!instDone) 120 return NULL; 121 instDone = false; 122 return decode(emi, nextPC.instAddr()); 123 } 124}; 125 126} // namespace MipsISA 127 128#endif // __ARCH_MIPS_DECODER_HH__ 129