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
35 static const unsigned RegisterDecode[] = {
36 M68k::D0, M68k::D1, M68k::D2, M68k::D3, M68k::D4, M68k::D5,
37 M68k::D6, M68k::D7, M68k::A0, M68k::A1, M68k::A2, M68k::A3,
38 M68k::A4, M68k::A5, M68k::A6, M68k::SP, M68k::FP0, M68k::FP1,
39 M68k::FP2, M68k::FP3, M68k::FP4, M68k::FP5, M68k::FP6, M68k::FP7,
40 M68k::FPIAR, M68k::FPS, M68k::FPC};
41
DecodeRegisterClass(MCInst & Inst,uint64_t RegNo,uint64_t Address,const void * Decoder)42 static DecodeStatus DecodeRegisterClass(MCInst &Inst, uint64_t RegNo,
43 uint64_t Address, const void *Decoder) {
44 if (RegNo >= 24)
45 return DecodeStatus::Fail;
46 Inst.addOperand(MCOperand::createReg(RegisterDecode[RegNo]));
47 return DecodeStatus::Success;
48 }
49
DecodeDR32RegisterClass(MCInst & Inst,uint64_t RegNo,uint64_t Address,const void * Decoder)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
DecodeDR16RegisterClass(MCInst & Inst,uint64_t RegNo,uint64_t Address,const void * Decoder)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
DecodeDR8RegisterClass(MCInst & Inst,uint64_t RegNo,uint64_t Address,const void * Decoder)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
DecodeAR32RegisterClass(MCInst & Inst,uint64_t RegNo,uint64_t Address,const void * Decoder)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
DecodeAR16RegisterClass(MCInst & Inst,uint64_t RegNo,uint64_t Address,const void * Decoder)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
DecodeXR32RegisterClass(MCInst & Inst,uint64_t RegNo,uint64_t Address,const void * Decoder)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
DecodeXR16RegisterClass(MCInst & Inst,uint64_t RegNo,uint64_t Address,const void * Decoder)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
DecodeFPDRRegisterClass(MCInst & Inst,uint64_t RegNo,uint64_t Address,const void * Decoder)92 static DecodeStatus DecodeFPDRRegisterClass(MCInst &Inst, uint64_t RegNo,
93 uint64_t Address,
94 const void *Decoder) {
95 return DecodeRegisterClass(Inst, RegNo | 16ULL, Address, Decoder);
96 }
97 #define DecodeFPDR32RegisterClass DecodeFPDRRegisterClass
98 #define DecodeFPDR64RegisterClass DecodeFPDRRegisterClass
99 #define DecodeFPDR80RegisterClass DecodeFPDRRegisterClass
100
DecodeFPCSCRegisterClass(MCInst & Inst,uint64_t RegNo,uint64_t Address,const void * Decoder)101 static DecodeStatus DecodeFPCSCRegisterClass(MCInst &Inst, uint64_t RegNo,
102 uint64_t Address,
103 const void *Decoder) {
104 return DecodeRegisterClass(Inst, (RegNo >> 1) + 24, Address, Decoder);
105 }
106 #define DecodeFPICRegisterClass DecodeFPCSCRegisterClass
107
DecodeCCRCRegisterClass(MCInst & Inst,APInt & Insn,uint64_t Address,const void * Decoder)108 static DecodeStatus DecodeCCRCRegisterClass(MCInst &Inst, APInt &Insn,
109 uint64_t Address,
110 const void *Decoder) {
111 llvm_unreachable("unimplemented");
112 }
113
DecodeImm32(MCInst & Inst,uint64_t Imm,uint64_t Address,const void * Decoder)114 static DecodeStatus DecodeImm32(MCInst &Inst, uint64_t Imm, uint64_t Address,
115 const void *Decoder) {
116 Inst.addOperand(MCOperand::createImm(M68k::swapWord<uint32_t>(Imm)));
117 return DecodeStatus::Success;
118 }
119
120 #include "M68kGenDisassemblerTable.inc"
121
122 #undef DecodeFPDR32RegisterClass
123 #undef DecodeFPDR64RegisterClass
124 #undef DecodeFPDR80RegisterClass
125 #undef DecodeFPICRegisterClass
126
127 /// A disassembler class for M68k.
128 struct M68kDisassembler : public MCDisassembler {
M68kDisassemblerM68kDisassembler129 M68kDisassembler(const MCSubtargetInfo &STI, MCContext &Ctx)
130 : MCDisassembler(STI, Ctx) {}
~M68kDisassemblerM68kDisassembler131 virtual ~M68kDisassembler() {}
132
133 DecodeStatus getInstruction(MCInst &Instr, uint64_t &Size,
134 ArrayRef<uint8_t> Bytes, uint64_t Address,
135 raw_ostream &CStream) const override;
136 };
137
getInstruction(MCInst & Instr,uint64_t & Size,ArrayRef<uint8_t> Bytes,uint64_t Address,raw_ostream & CStream) const138 DecodeStatus M68kDisassembler::getInstruction(MCInst &Instr, uint64_t &Size,
139 ArrayRef<uint8_t> Bytes,
140 uint64_t Address,
141 raw_ostream &CStream) const {
142 DecodeStatus Result;
143 auto MakeUp = [&](APInt &Insn, unsigned InstrBits) {
144 unsigned Idx = Insn.getBitWidth() >> 3;
145 unsigned RoundUp = alignTo(InstrBits, Align(16));
146 if (RoundUp > Insn.getBitWidth())
147 Insn = Insn.zext(RoundUp);
148 RoundUp = RoundUp >> 3;
149 for (; Idx < RoundUp; Idx += 2) {
150 Insn.insertBits(support::endian::read16be(&Bytes[Idx]), Idx * 8, 16);
151 }
152 };
153 APInt Insn(16, support::endian::read16be(Bytes.data()));
154 // 2 bytes of data are consumed, so set Size to 2
155 // If we don't do this, disassembler may generate result even
156 // the encoding is invalid. We need to let it fail correctly.
157 Size = 2;
158 Result = decodeInstruction(DecoderTable80, Instr, Insn, Address, this, STI,
159 MakeUp);
160 if (Result == DecodeStatus::Success)
161 Size = InstrLenTable[Instr.getOpcode()] >> 3;
162 return Result;
163 }
164
createM68kDisassembler(const Target & T,const MCSubtargetInfo & STI,MCContext & Ctx)165 static MCDisassembler *createM68kDisassembler(const Target &T,
166 const MCSubtargetInfo &STI,
167 MCContext &Ctx) {
168 return new M68kDisassembler(STI, Ctx);
169 }
170
LLVMInitializeM68kDisassembler()171 extern "C" LLVM_EXTERNAL_VISIBILITY void LLVMInitializeM68kDisassembler() {
172 // Register the disassembler.
173 TargetRegistry::RegisterMCDisassembler(getTheM68kTarget(),
174 createM68kDisassembler);
175 }
176