243 lines
		
	
	
		
			8.5 KiB
		
	
	
	
		
			C++
		
	
	
	
			
		
		
	
	
			243 lines
		
	
	
		
			8.5 KiB
		
	
	
	
		
			C++
		
	
	
	
//===- LanaiDisassembler.cpp - Disassembler for Lanai -----------*- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// This file is part of the Lanai Disassembler.
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//
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//===----------------------------------------------------------------------===//
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#include "LanaiDisassembler.h"
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#include "LanaiAluCode.h"
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#include "LanaiCondCode.h"
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#include "LanaiInstrInfo.h"
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#include "TargetInfo/LanaiTargetInfo.h"
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#include "llvm/MC/MCFixedLenDisassembler.h"
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#include "llvm/MC/MCInst.h"
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#include "llvm/MC/MCSubtargetInfo.h"
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#include "llvm/Support/MathExtras.h"
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#include "llvm/Support/TargetRegistry.h"
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using namespace llvm;
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typedef MCDisassembler::DecodeStatus DecodeStatus;
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namespace llvm {
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Target &getTheLanaiTarget();
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}
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static MCDisassembler *createLanaiDisassembler(const Target & /*T*/,
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                                               const MCSubtargetInfo &STI,
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                                               MCContext &Ctx) {
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  return new LanaiDisassembler(STI, Ctx);
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}
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extern "C" LLVM_EXTERNAL_VISIBILITY void LLVMInitializeLanaiDisassembler() {
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  // Register the disassembler
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  TargetRegistry::RegisterMCDisassembler(getTheLanaiTarget(),
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                                         createLanaiDisassembler);
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}
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LanaiDisassembler::LanaiDisassembler(const MCSubtargetInfo &STI, MCContext &Ctx)
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    : MCDisassembler(STI, Ctx) {}
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// Forward declare because the autogenerated code will reference this.
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// Definition is further down.
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static DecodeStatus DecodeGPRRegisterClass(MCInst &Inst, unsigned RegNo,
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                                           uint64_t Address,
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                                           const void *Decoder);
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static DecodeStatus decodeRiMemoryValue(MCInst &Inst, unsigned Insn,
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                                        uint64_t Address, const void *Decoder);
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static DecodeStatus decodeRrMemoryValue(MCInst &Inst, unsigned Insn,
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                                        uint64_t Address, const void *Decoder);
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static DecodeStatus decodeSplsValue(MCInst &Inst, unsigned Insn,
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                                    uint64_t Address, const void *Decoder);
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static DecodeStatus decodeBranch(MCInst &Inst, unsigned Insn, uint64_t Address,
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                                 const void *Decoder);
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static DecodeStatus decodePredicateOperand(MCInst &Inst, unsigned Val,
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                                           uint64_t Address,
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                                           const void *Decoder);
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static DecodeStatus decodeShiftImm(MCInst &Inst, unsigned Insn,
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                                   uint64_t Address, const void *Decoder);
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#include "LanaiGenDisassemblerTables.inc"
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static DecodeStatus readInstruction32(ArrayRef<uint8_t> Bytes, uint64_t &Size,
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                                      uint32_t &Insn) {
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  // We want to read exactly 4 bytes of data.
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  if (Bytes.size() < 4) {
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    Size = 0;
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    return MCDisassembler::Fail;
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  }
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  // Encoded as big-endian 32-bit word in the stream.
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  Insn =
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      (Bytes[0] << 24) | (Bytes[1] << 16) | (Bytes[2] << 8) | (Bytes[3] << 0);
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  return MCDisassembler::Success;
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}
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static void PostOperandDecodeAdjust(MCInst &Instr, uint32_t Insn) {
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  unsigned AluOp = LPAC::ADD;
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  // Fix up for pre and post operations.
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  int PqShift = -1;
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  if (isRMOpcode(Instr.getOpcode()))
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    PqShift = 16;
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  else if (isSPLSOpcode(Instr.getOpcode()))
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    PqShift = 10;
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  else if (isRRMOpcode(Instr.getOpcode())) {
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    PqShift = 16;
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    // Determine RRM ALU op.
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    AluOp = (Insn >> 8) & 0x7;
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    if (AluOp == 7)
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      // Handle JJJJJ
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      // 0b10000 or 0b11000
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      AluOp |= 0x20 | (((Insn >> 3) & 0xf) << 1);
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  }
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  if (PqShift != -1) {
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    unsigned PQ = (Insn >> PqShift) & 0x3;
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    switch (PQ) {
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    case 0x0:
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      if (Instr.getOperand(2).isReg()) {
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        Instr.getOperand(2).setReg(Lanai::R0);
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      }
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      if (Instr.getOperand(2).isImm())
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        Instr.getOperand(2).setImm(0);
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      break;
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    case 0x1:
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      AluOp = LPAC::makePostOp(AluOp);
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      break;
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    case 0x2:
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      break;
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    case 0x3:
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      AluOp = LPAC::makePreOp(AluOp);
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      break;
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    }
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    Instr.addOperand(MCOperand::createImm(AluOp));
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  }
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}
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DecodeStatus
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LanaiDisassembler::getInstruction(MCInst &Instr, uint64_t &Size,
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                                  ArrayRef<uint8_t> Bytes, uint64_t Address,
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                                  raw_ostream & /*CStream*/) const {
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  uint32_t Insn;
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  DecodeStatus Result = readInstruction32(Bytes, Size, Insn);
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  if (Result == MCDisassembler::Fail)
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    return MCDisassembler::Fail;
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  // Call auto-generated decoder function
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  Result =
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      decodeInstruction(DecoderTableLanai32, Instr, Insn, Address, this, STI);
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  if (Result != MCDisassembler::Fail) {
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    PostOperandDecodeAdjust(Instr, Insn);
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    Size = 4;
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    return Result;
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  }
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  return MCDisassembler::Fail;
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}
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static const unsigned GPRDecoderTable[] = {
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    Lanai::R0,  Lanai::R1,  Lanai::PC,  Lanai::R3,  Lanai::SP,  Lanai::FP,
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    Lanai::R6,  Lanai::R7,  Lanai::RV,  Lanai::R9,  Lanai::RR1, Lanai::RR2,
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    Lanai::R12, Lanai::R13, Lanai::R14, Lanai::RCA, Lanai::R16, Lanai::R17,
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    Lanai::R18, Lanai::R19, Lanai::R20, Lanai::R21, Lanai::R22, Lanai::R23,
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    Lanai::R24, Lanai::R25, Lanai::R26, Lanai::R27, Lanai::R28, Lanai::R29,
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    Lanai::R30, Lanai::R31};
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DecodeStatus DecodeGPRRegisterClass(MCInst &Inst, unsigned RegNo,
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                                    uint64_t /*Address*/,
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                                    const void * /*Decoder*/) {
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  if (RegNo > 31)
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    return MCDisassembler::Fail;
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  unsigned Reg = GPRDecoderTable[RegNo];
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  Inst.addOperand(MCOperand::createReg(Reg));
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  return MCDisassembler::Success;
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}
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static DecodeStatus decodeRiMemoryValue(MCInst &Inst, unsigned Insn,
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                                        uint64_t Address, const void *Decoder) {
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  // RI memory values encoded using 23 bits:
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  //   5 bit register, 16 bit constant
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  unsigned Register = (Insn >> 18) & 0x1f;
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  Inst.addOperand(MCOperand::createReg(GPRDecoderTable[Register]));
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  unsigned Offset = (Insn & 0xffff);
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  Inst.addOperand(MCOperand::createImm(SignExtend32<16>(Offset)));
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  return MCDisassembler::Success;
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}
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static DecodeStatus decodeRrMemoryValue(MCInst &Inst, unsigned Insn,
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                                        uint64_t Address, const void *Decoder) {
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  // RR memory values encoded using 20 bits:
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  //   5 bit register, 5 bit register, 2 bit PQ, 3 bit ALU operator, 5 bit JJJJJ
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  unsigned Register = (Insn >> 15) & 0x1f;
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  Inst.addOperand(MCOperand::createReg(GPRDecoderTable[Register]));
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  Register = (Insn >> 10) & 0x1f;
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  Inst.addOperand(MCOperand::createReg(GPRDecoderTable[Register]));
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  return MCDisassembler::Success;
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}
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static DecodeStatus decodeSplsValue(MCInst &Inst, unsigned Insn,
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                                    uint64_t Address, const void *Decoder) {
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  // RI memory values encoded using 17 bits:
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  //   5 bit register, 10 bit constant
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  unsigned Register = (Insn >> 12) & 0x1f;
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  Inst.addOperand(MCOperand::createReg(GPRDecoderTable[Register]));
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  unsigned Offset = (Insn & 0x3ff);
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  Inst.addOperand(MCOperand::createImm(SignExtend32<10>(Offset)));
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  return MCDisassembler::Success;
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}
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static bool tryAddingSymbolicOperand(int64_t Value, bool IsBranch,
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                                     uint64_t Address, uint64_t Offset,
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                                     uint64_t Width, MCInst &MI,
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                                     const void *Decoder) {
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  const MCDisassembler *Dis = static_cast<const MCDisassembler *>(Decoder);
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  return Dis->tryAddingSymbolicOperand(MI, Value, Address, IsBranch, Offset,
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                                       Width);
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}
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static DecodeStatus decodeBranch(MCInst &MI, unsigned Insn, uint64_t Address,
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                                 const void *Decoder) {
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  if (!tryAddingSymbolicOperand(Insn + Address, false, Address, 2, 23, MI,
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                                Decoder))
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    MI.addOperand(MCOperand::createImm(Insn));
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  return MCDisassembler::Success;
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}
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static DecodeStatus decodeShiftImm(MCInst &Inst, unsigned Insn,
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                                   uint64_t Address, const void *Decoder) {
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  unsigned Offset = (Insn & 0xffff);
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  Inst.addOperand(MCOperand::createImm(SignExtend32<16>(Offset)));
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  return MCDisassembler::Success;
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}
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static DecodeStatus decodePredicateOperand(MCInst &Inst, unsigned Val,
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                                           uint64_t Address,
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                                           const void *Decoder) {
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  if (Val >= LPCC::UNKNOWN)
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    return MCDisassembler::Fail;
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  Inst.addOperand(MCOperand::createImm(Val));
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  return MCDisassembler::Success;
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}
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