decoder.hh revision 9377
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_POWER_DECODER_HH__ 32#define __ARCH_POWER_DECODER_HH__ 33 34#include "arch/generic/decode_cache.hh" 35#include "arch/types.hh" 36#include "cpu/static_inst.hh" 37 38namespace PowerISA 39{ 40 41class Decoder 42{ 43 protected: 44 // The extended machine instruction being generated 45 ExtMachInst emi; 46 bool instDone; 47 48 public: 49 Decoder() : instDone(false) 50 { 51 } 52 53 void 54 process() 55 { 56 } 57 58 void 59 reset() 60 { 61 instDone = false; 62 } 63 64 // Use this to give data to the predecoder. This should be used 65 // when there is control flow. 66 void 67 moreBytes(const PCState &pc, Addr fetchPC, MachInst inst) 68 { 69 emi = inst; 70 instDone = true; 71 } 72 73 // Use this to give data to the predecoder. This should be used 74 // when instructions are executed in order. 75 void 76 moreBytes(MachInst machInst) 77 { 78 moreBytes(0, 0, machInst); 79 } 80 81 bool 82 needMoreBytes() 83 { 84 return true; 85 } 86 87 bool 88 instReady() 89 { 90 return instDone; 91 } 92 protected: 93 /// A cache of decoded instruction objects. 94 static GenericISA::BasicDecodeCache defaultCache; 95 96 public: 97 StaticInstPtr decodeInst(ExtMachInst mach_inst); 98 99 /// Decode a machine instruction. 100 /// @param mach_inst The binary instruction to decode. 101 /// @retval A pointer to the corresponding StaticInst object. 102 StaticInstPtr 103 decode(ExtMachInst mach_inst, Addr addr) 104 { 105 return defaultCache.decode(this, mach_inst, addr); 106 } 107 108 StaticInstPtr 109 decode(PowerISA::PCState &nextPC) 110 { 111 if (!instDone) 112 return NULL; 113 instDone = false; 114 return decode(emi, nextPC.instAddr()); 115 } 116}; 117 118} // namespace PowerISA 119 120#endif // __ARCH_POWER_DECODER_HH__ 121