1 //===-- M68kDisassembler.cpp - Disassembler for M68k ------------*- C++ -*-===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 // This file is part of the M68k Disassembler. 10 // 11 //===----------------------------------------------------------------------===// 12 13 #include "M68k.h" 14 #include "M68kRegisterInfo.h" 15 #include "M68kSubtarget.h" 16 #include "MCTargetDesc/M68kMCCodeEmitter.h" 17 #include "MCTargetDesc/M68kMCTargetDesc.h" 18 #include "TargetInfo/M68kTargetInfo.h" 19 20 #include "llvm/MC/MCAsmInfo.h" 21 #include "llvm/MC/MCContext.h" 22 #include "llvm/MC/MCDisassembler/MCDisassembler.h" 23 #include "llvm/MC/MCDecoderOps.h" 24 #include "llvm/MC/MCInst.h" 25 #include "llvm/MC/TargetRegistry.h" 26 #include "llvm/Support/Endian.h" 27 #include "llvm/Support/ErrorHandling.h" 28 29 using namespace llvm; 30 31 #define DEBUG_TYPE "m68k-disassembler" 32 33 typedef MCDisassembler::DecodeStatus DecodeStatus; 34 const unsigned MaxInstrWord = 11; 35 36 static const unsigned RegisterDecode[] = { 37 M68k::D0, M68k::D1, M68k::D2, M68k::D3, M68k::D4, M68k::D5, 38 M68k::D6, M68k::D7, M68k::A0, M68k::A1, M68k::A2, M68k::A3, 39 M68k::A4, M68k::A5, M68k::A6, M68k::SP, 40 }; 41 42 static DecodeStatus DecodeRegisterClass(MCInst &Inst, uint64_t RegNo, 43 uint64_t Address, const void *Decoder) { 44 if (RegNo >= 16) 45 return DecodeStatus::Fail; 46 Inst.addOperand(MCOperand::createReg(RegisterDecode[RegNo])); 47 return DecodeStatus::Success; 48 } 49 50 static DecodeStatus DecodeDR32RegisterClass(MCInst &Inst, uint64_t RegNo, 51 uint64_t Address, 52 const void *Decoder) { 53 return DecodeRegisterClass(Inst, RegNo, Address, Decoder); 54 } 55 56 static DecodeStatus DecodeDR16RegisterClass(MCInst &Inst, uint64_t RegNo, 57 uint64_t Address, 58 const void *Decoder) { 59 return DecodeRegisterClass(Inst, RegNo, Address, Decoder); 60 } 61 62 static DecodeStatus DecodeDR8RegisterClass(MCInst &Inst, uint64_t RegNo, 63 uint64_t Address, 64 const void *Decoder) { 65 return DecodeRegisterClass(Inst, RegNo, Address, Decoder); 66 } 67 68 static DecodeStatus DecodeAR32RegisterClass(MCInst &Inst, uint64_t RegNo, 69 uint64_t Address, 70 const void *Decoder) { 71 return DecodeRegisterClass(Inst, RegNo | 8ULL, Address, Decoder); 72 } 73 74 static DecodeStatus DecodeAR16RegisterClass(MCInst &Inst, uint64_t RegNo, 75 uint64_t Address, 76 const void *Decoder) { 77 return DecodeRegisterClass(Inst, RegNo | 8ULL, Address, Decoder); 78 } 79 80 static DecodeStatus DecodeXR32RegisterClass(MCInst &Inst, uint64_t RegNo, 81 uint64_t Address, 82 const void *Decoder) { 83 return DecodeRegisterClass(Inst, RegNo, Address, Decoder); 84 } 85 86 static DecodeStatus DecodeXR16RegisterClass(MCInst &Inst, uint64_t RegNo, 87 uint64_t Address, 88 const void *Decoder) { 89 return DecodeRegisterClass(Inst, RegNo, Address, Decoder); 90 } 91 92 static DecodeStatus DecodeCCRCRegisterClass(MCInst &Inst, APInt &Insn, 93 uint64_t Address, 94 const void *Decoder) { 95 llvm_unreachable("unimplemented"); 96 } 97 98 #include "M68kGenDisassemblerTable.inc" 99 100 /// A disassembler class for M68k. 101 class M68kDisassembler : public MCDisassembler { 102 MCInstrInfo *MCII; 103 104 public: 105 M68kDisassembler(const MCSubtargetInfo &STI, MCContext &Ctx, 106 MCInstrInfo *MCII) 107 : MCDisassembler(STI, Ctx), MCII(MCII) {} 108 virtual ~M68kDisassembler() {} 109 110 DecodeStatus getInstruction(MCInst &Instr, uint64_t &Size, 111 ArrayRef<uint8_t> Bytes, uint64_t Address, 112 raw_ostream &CStream) const override; 113 }; 114 115 DecodeStatus M68kDisassembler::getInstruction(MCInst &Instr, uint64_t &Size, 116 ArrayRef<uint8_t> Bytes, 117 uint64_t Address, 118 raw_ostream &CStream) const { 119 DecodeStatus Result; 120 auto MakeUp = [&](APInt &Insn, unsigned InstrBits) { 121 unsigned Idx = Insn.getBitWidth() >> 3; 122 unsigned RoundUp = alignTo(InstrBits, Align(16)); 123 Insn = Insn.zextOrSelf(RoundUp); 124 RoundUp = RoundUp >> 3; 125 for (; Idx < RoundUp; Idx += 2) { 126 Insn.insertBits(support::endian::read16be(&Bytes[Idx]), Idx * 8, 16); 127 } 128 }; 129 APInt Insn(16, support::endian::read16be(Bytes.data())); 130 // 2 bytes of data are consumed, so set Size to 2 131 // If we don't do this, disassembler may generate result even 132 // the encoding is invalid. We need to let it fail correctly. 133 Size = 2; 134 Result = decodeInstruction(DecoderTable80, Instr, Insn, Address, this, STI, 135 MakeUp); 136 if (Result == DecodeStatus::Success) 137 Size = InstrLenTable[Instr.getOpcode()] >> 3; 138 return Result; 139 } 140 141 static MCDisassembler *createM68kDisassembler(const Target &T, 142 const MCSubtargetInfo &STI, 143 MCContext &Ctx) { 144 return new M68kDisassembler(STI, Ctx, T.createMCInstrInfo()); 145 } 146 147 extern "C" LLVM_EXTERNAL_VISIBILITY void LLVMInitializeM68kDisassembler() { 148 // Register the disassembler. 149 TargetRegistry::RegisterMCDisassembler(getTheM68kTarget(), 150 createM68kDisassembler); 151 } 152