llvm-6502/lib/Target/XCore/Disassembler/XCoreDisassembler.cpp

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//===- XCoreDisassembler.cpp - Disassembler for XCore -----------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
///
/// \file
/// \brief This file is part of the XCore Disassembler.
///
//===----------------------------------------------------------------------===//
#include "XCore.h"
#include "XCoreRegisterInfo.h"
#include "llvm/MC/MCDisassembler.h"
#include "llvm/MC/MCFixedLenDisassembler.h"
#include "llvm/MC/MCInst.h"
#include "llvm/MC/MCSubtargetInfo.h"
#include "llvm/Support/MemoryObject.h"
#include "llvm/Support/TargetRegistry.h"
using namespace llvm;
typedef MCDisassembler::DecodeStatus DecodeStatus;
namespace {
/// \brief A disassembler class for XCore.
class XCoreDisassembler : public MCDisassembler {
const MCRegisterInfo *RegInfo;
public:
XCoreDisassembler(const MCSubtargetInfo &STI, const MCRegisterInfo *Info) :
MCDisassembler(STI), RegInfo(Info) {}
/// \brief See MCDisassembler.
virtual DecodeStatus getInstruction(MCInst &instr,
uint64_t &size,
const MemoryObject &region,
uint64_t address,
raw_ostream &vStream,
raw_ostream &cStream) const;
const MCRegisterInfo *getRegInfo() const { return RegInfo; }
};
}
static bool readInstruction16(const MemoryObject &region,
uint64_t address,
uint64_t &size,
uint16_t &insn) {
uint8_t Bytes[4];
// We want to read exactly 2 Bytes of data.
if (region.readBytes(address, 2, Bytes, NULL) == -1) {
size = 0;
return false;
}
// Encoded as a little-endian 16-bit word in the stream.
insn = (Bytes[0] << 0) | (Bytes[1] << 8);
return true;
}
static unsigned getReg(const void *D, unsigned RC, unsigned RegNo) {
const XCoreDisassembler *Dis = static_cast<const XCoreDisassembler*>(D);
return *(Dis->getRegInfo()->getRegClass(RC).begin() + RegNo);
}
static DecodeStatus DecodeGRRegsRegisterClass(MCInst &Inst,
unsigned RegNo,
uint64_t Address,
const void *Decoder);
static DecodeStatus DecodeBitpOperand(MCInst &Inst, unsigned Val,
uint64_t Address, const void *Decoder);
static DecodeStatus Decode2RInstruction(MCInst &Inst,
unsigned Insn,
uint64_t Address,
const void *Decoder);
static DecodeStatus DecodeR2RInstruction(MCInst &Inst,
unsigned Insn,
uint64_t Address,
const void *Decoder);
static DecodeStatus Decode2RSrcDstInstruction(MCInst &Inst,
unsigned Insn,
uint64_t Address,
const void *Decoder);
static DecodeStatus DecodeRUSInstruction(MCInst &Inst,
unsigned Insn,
uint64_t Address,
const void *Decoder);
static DecodeStatus DecodeRUSBitpInstruction(MCInst &Inst,
unsigned Insn,
uint64_t Address,
const void *Decoder);
static DecodeStatus DecodeRUSSrcDstBitpInstruction(MCInst &Inst,
unsigned Insn,
uint64_t Address,
const void *Decoder);
#include "XCoreGenDisassemblerTables.inc"
static DecodeStatus DecodeGRRegsRegisterClass(MCInst &Inst,
unsigned RegNo,
uint64_t Address,
const void *Decoder)
{
if (RegNo > 11)
return MCDisassembler::Fail;
unsigned Reg = getReg(Decoder, XCore::GRRegsRegClassID, RegNo);
Inst.addOperand(MCOperand::CreateReg(Reg));
return MCDisassembler::Success;
}
static DecodeStatus DecodeBitpOperand(MCInst &Inst, unsigned Val,
uint64_t Address, const void *Decoder) {
if (Val > 11)
return MCDisassembler::Fail;
static unsigned Values[] = {
32 /*bpw*/, 1, 2, 3, 4, 5, 6, 7, 8, 16, 24, 32
};
Inst.addOperand(MCOperand::CreateImm(Values[Val]));
return MCDisassembler::Success;
}
static DecodeStatus
Decode2OpInstruction(unsigned Insn, unsigned &Op1, unsigned &Op2) {
unsigned Combined = fieldFromInstruction(Insn, 6, 5) +
fieldFromInstruction(Insn, 5, 1) * 5 - 27;
if (Combined >= 9)
return MCDisassembler::Fail;
unsigned Op1High = Combined % 3;
unsigned Op2High = Combined / 3;
Op1 = (Op1High << 2) | fieldFromInstruction(Insn, 2, 2);
Op2 = (Op2High << 2) | fieldFromInstruction(Insn, 0, 2);
return MCDisassembler::Success;
}
static DecodeStatus
Decode2RInstruction(MCInst &Inst, unsigned Insn, uint64_t Address,
const void *Decoder) {
unsigned Op1, Op2;
DecodeStatus S = Decode2OpInstruction(Insn, Op1, Op2);
if (S == MCDisassembler::Success) {
DecodeGRRegsRegisterClass(Inst, Op1, Address, Decoder);
DecodeGRRegsRegisterClass(Inst, Op2, Address, Decoder);
}
return S;
}
static DecodeStatus
DecodeR2RInstruction(MCInst &Inst, unsigned Insn, uint64_t Address,
const void *Decoder) {
unsigned Op1, Op2;
DecodeStatus S = Decode2OpInstruction(Insn, Op2, Op1);
if (S == MCDisassembler::Success) {
DecodeGRRegsRegisterClass(Inst, Op1, Address, Decoder);
DecodeGRRegsRegisterClass(Inst, Op2, Address, Decoder);
}
return S;
}
static DecodeStatus
Decode2RSrcDstInstruction(MCInst &Inst, unsigned Insn, uint64_t Address,
const void *Decoder) {
unsigned Op1, Op2;
DecodeStatus S = Decode2OpInstruction(Insn, Op1, Op2);
if (S == MCDisassembler::Success) {
DecodeGRRegsRegisterClass(Inst, Op1, Address, Decoder);
DecodeGRRegsRegisterClass(Inst, Op1, Address, Decoder);
DecodeGRRegsRegisterClass(Inst, Op2, Address, Decoder);
}
return S;
}
static DecodeStatus
DecodeRUSInstruction(MCInst &Inst, unsigned Insn, uint64_t Address,
const void *Decoder) {
unsigned Op1, Op2;
DecodeStatus S = Decode2OpInstruction(Insn, Op1, Op2);
if (S == MCDisassembler::Success) {
DecodeGRRegsRegisterClass(Inst, Op1, Address, Decoder);
Inst.addOperand(MCOperand::CreateImm(Op2));
}
return S;
}
static DecodeStatus
DecodeRUSBitpInstruction(MCInst &Inst, unsigned Insn, uint64_t Address,
const void *Decoder) {
unsigned Op1, Op2;
DecodeStatus S = Decode2OpInstruction(Insn, Op1, Op2);
if (S == MCDisassembler::Success) {
DecodeGRRegsRegisterClass(Inst, Op1, Address, Decoder);
DecodeBitpOperand(Inst, Op2, Address, Decoder);
}
return S;
}
static DecodeStatus
DecodeRUSSrcDstBitpInstruction(MCInst &Inst, unsigned Insn, uint64_t Address,
const void *Decoder) {
unsigned Op1, Op2;
DecodeStatus S = Decode2OpInstruction(Insn, Op1, Op2);
if (S == MCDisassembler::Success) {
DecodeGRRegsRegisterClass(Inst, Op1, Address, Decoder);
DecodeGRRegsRegisterClass(Inst, Op1, Address, Decoder);
DecodeBitpOperand(Inst, Op2, Address, Decoder);
}
return S;
}
MCDisassembler::DecodeStatus
XCoreDisassembler::getInstruction(MCInst &instr,
uint64_t &Size,
const MemoryObject &Region,
uint64_t Address,
raw_ostream &vStream,
raw_ostream &cStream) const {
uint16_t low;
if (!readInstruction16(Region, Address, Size, low)) {
return Fail;
}
// Calling the auto-generated decoder function.
DecodeStatus Result = decodeInstruction(DecoderTable16, instr, low, Address,
this, STI);
if (Result != Fail) {
Size = 2;
return Result;
}
return Fail;
}
namespace llvm {
extern Target TheXCoreTarget;
}
static MCDisassembler *createXCoreDisassembler(const Target &T,
const MCSubtargetInfo &STI) {
return new XCoreDisassembler(STI, T.createMCRegInfo(""));
}
extern "C" void LLVMInitializeXCoreDisassembler() {
// Register the disassembler.
TargetRegistry::RegisterMCDisassembler(TheXCoreTarget,
createXCoreDisassembler);
}