Rename A64 port to ARM64 port

src/a64/simulator-a64.cc

-// Copyright 2013 the V8 project authors. All rights reserved.
-// Redistribution and use in source and binary forms, with or without
-// modification, are permitted provided that the following conditions are
-// met:
-//
-//     * Redistributions of source code must retain the above copyright
-//       notice, this list of conditions and the following disclaimer.
-//     * Redistributions in binary form must reproduce the above
-//       copyright notice, this list of conditions and the following
-//       disclaimer in the documentation and/or other materials provided
-//       with the distribution.
-//     * Neither the name of Google Inc. nor the names of its
-//       contributors may be used to endorse or promote products derived
-//       from this software without specific prior written permission.
-//
-// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
-// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
-// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
-// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
-// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
-// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
-// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
-// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
-// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
-// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
-// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-
-#include <stdlib.h>
-#include <cmath>
-#include <cstdarg>
-#include "v8.h"
-
-#if V8_TARGET_ARCH_A64
-
-#include "disasm.h"
-#include "assembler.h"
-#include "a64/decoder-a64-inl.h"
-#include "a64/simulator-a64.h"
-#include "macro-assembler.h"
-
-namespace v8 {
-namespace internal {
-
-#if defined(USE_SIMULATOR)
-
-
-// This macro provides a platform independent use of sscanf. The reason for
-// SScanF not being implemented in a platform independent way through
-// ::v8::internal::OS in the same way as SNPrintF is that the
-// Windows C Run-Time Library does not provide vsscanf.
-#define SScanF sscanf  // NOLINT
-
-
-// Helpers for colors.
-// Depending on your terminal configuration, the colour names may not match the
-// observed colours.
-#define COLOUR(colour_code)  "\033[" colour_code "m"
-#define BOLD(colour_code)    "1;" colour_code
-#define NORMAL ""
-#define GREY   "30"
-#define GREEN  "32"
-#define ORANGE "33"
-#define BLUE   "34"
-#define PURPLE "35"
-#define INDIGO "36"
-#define WHITE  "37"
-typedef char const * const TEXT_COLOUR;
-TEXT_COLOUR clr_normal         = FLAG_log_colour ? COLOUR(NORMAL)       : "";
-TEXT_COLOUR clr_flag_name      = FLAG_log_colour ? COLOUR(BOLD(GREY))   : "";
-TEXT_COLOUR clr_flag_value     = FLAG_log_colour ? COLOUR(BOLD(WHITE))  : "";
-TEXT_COLOUR clr_reg_name       = FLAG_log_colour ? COLOUR(BOLD(BLUE))   : "";
-TEXT_COLOUR clr_reg_value      = FLAG_log_colour ? COLOUR(BOLD(INDIGO)) : "";
-TEXT_COLOUR clr_fpreg_name     = FLAG_log_colour ? COLOUR(BOLD(ORANGE)) : "";
-TEXT_COLOUR clr_fpreg_value    = FLAG_log_colour ? COLOUR(BOLD(PURPLE)) : "";
-TEXT_COLOUR clr_memory_value   = FLAG_log_colour ? COLOUR(BOLD(GREEN))  : "";
-TEXT_COLOUR clr_memory_address = FLAG_log_colour ? COLOUR(GREEN)        : "";
-TEXT_COLOUR clr_debug_number   = FLAG_log_colour ? COLOUR(BOLD(ORANGE)) : "";
-TEXT_COLOUR clr_debug_message  = FLAG_log_colour ? COLOUR(ORANGE)       : "";
-TEXT_COLOUR clr_printf         = FLAG_log_colour ? COLOUR(GREEN)        : "";
-
-
-// This is basically the same as PrintF, with a guard for FLAG_trace_sim.
-void PRINTF_CHECKING TraceSim(const char* format, ...) {
-  if (FLAG_trace_sim) {
-    va_list arguments;
-    va_start(arguments, format);
-    OS::VPrint(format, arguments);
-    va_end(arguments);
-  }
-}
-
-
-const Instruction* Simulator::kEndOfSimAddress = NULL;
-
-
-void SimSystemRegister::SetBits(int msb, int lsb, uint32_t bits) {
-  int width = msb - lsb + 1;
-  ASSERT(is_uintn(bits, width) || is_intn(bits, width));
-
-  bits <<= lsb;
-  uint32_t mask = ((1 << width) - 1) << lsb;
-  ASSERT((mask & write_ignore_mask_) == 0);
-
-  value_ = (value_ & ~mask) | (bits & mask);
-}
-
-
-SimSystemRegister SimSystemRegister::DefaultValueFor(SystemRegister id) {
-  switch (id) {
-    case NZCV:
-      return SimSystemRegister(0x00000000, NZCVWriteIgnoreMask);
-    case FPCR:
-      return SimSystemRegister(0x00000000, FPCRWriteIgnoreMask);
-    default:
-      UNREACHABLE();
-      return SimSystemRegister();
-  }
-}
-
-
-void Simulator::Initialize(Isolate* isolate) {
-  if (isolate->simulator_initialized()) return;
-  isolate->set_simulator_initialized(true);
-  ExternalReference::set_redirector(isolate, &RedirectExternalReference);
-}
-
-
-// Get the active Simulator for the current thread.
-Simulator* Simulator::current(Isolate* isolate) {
-  Isolate::PerIsolateThreadData* isolate_data =
-      isolate->FindOrAllocatePerThreadDataForThisThread();
-  ASSERT(isolate_data != NULL);
-
-  Simulator* sim = isolate_data->simulator();
-  if (sim == NULL) {
-    if (FLAG_trace_sim || FLAG_log_instruction_stats || FLAG_debug_sim) {
-      sim = new Simulator(new Decoder<DispatchingDecoderVisitor>(), isolate);
-    } else {
-      sim = new Decoder<Simulator>();
-      sim->isolate_ = isolate;
-    }
-    isolate_data->set_simulator(sim);
-  }
-  return sim;
-}
-
-
-void Simulator::CallVoid(byte* entry, CallArgument* args) {
-  int index_x = 0;
-  int index_d = 0;
-
-  std::vector<int64_t> stack_args(0);
-  for (int i = 0; !args[i].IsEnd(); i++) {
-    CallArgument arg = args[i];
-    if (arg.IsX() && (index_x < 8)) {
-      set_xreg(index_x++, arg.bits());
-    } else if (arg.IsD() && (index_d < 8)) {
-      set_dreg_bits(index_d++, arg.bits());
-    } else {
-      ASSERT(arg.IsD() || arg.IsX());
-      stack_args.push_back(arg.bits());
-    }
-  }
-
-  // Process stack arguments, and make sure the stack is suitably aligned.
-  uintptr_t original_stack = sp();
-  uintptr_t entry_stack = original_stack -
-                          stack_args.size() * sizeof(stack_args[0]);
-  if (OS::ActivationFrameAlignment() != 0) {
-    entry_stack &= -OS::ActivationFrameAlignment();
-  }
-  char * stack = reinterpret_cast<char*>(entry_stack);
-  std::vector<int64_t>::const_iterator it;
-  for (it = stack_args.begin(); it != stack_args.end(); it++) {
-    memcpy(stack, &(*it), sizeof(*it));
-    stack += sizeof(*it);
-  }
-
-  ASSERT(reinterpret_cast<uintptr_t>(stack) <= original_stack);
-  set_sp(entry_stack);
-
-  // Call the generated code.
-  set_pc(entry);
-  set_lr(kEndOfSimAddress);
-  CheckPCSComplianceAndRun();
-
-  set_sp(original_stack);
-}
-
-
-int64_t Simulator::CallInt64(byte* entry, CallArgument* args) {
-  CallVoid(entry, args);
-  return xreg(0);
-}
-
-
-double Simulator::CallDouble(byte* entry, CallArgument* args) {
-  CallVoid(entry, args);
-  return dreg(0);
-}
-
-
-int64_t Simulator::CallJS(byte* entry,
-                          byte* function_entry,
-                          JSFunction* func,
-                          Object* revc,
-                          int64_t argc,
-                          Object*** argv) {
-  CallArgument args[] = {
-    CallArgument(function_entry),
-    CallArgument(func),
-    CallArgument(revc),
-    CallArgument(argc),
-    CallArgument(argv),
-    CallArgument::End()
-  };
-  return CallInt64(entry, args);
-}
-
-int64_t Simulator::CallRegExp(byte* entry,
-                              String* input,
-                              int64_t start_offset,
-                              const byte* input_start,
-                              const byte* input_end,
-                              int* output,
-                              int64_t output_size,
-                              Address stack_base,
-                              int64_t direct_call,
-                              void* return_address,
-                              Isolate* isolate) {
-  CallArgument args[] = {
-    CallArgument(input),
-    CallArgument(start_offset),
-    CallArgument(input_start),
-    CallArgument(input_end),
-    CallArgument(output),
-    CallArgument(output_size),
-    CallArgument(stack_base),
-    CallArgument(direct_call),
-    CallArgument(return_address),
-    CallArgument(isolate),
-    CallArgument::End()
-  };
-  return CallInt64(entry, args);
-}
-
-
-void Simulator::CheckPCSComplianceAndRun() {
-#ifdef DEBUG
-  CHECK_EQ(kNumberOfCalleeSavedRegisters, kCalleeSaved.Count());
-  CHECK_EQ(kNumberOfCalleeSavedFPRegisters, kCalleeSavedFP.Count());
-
-  int64_t saved_registers[kNumberOfCalleeSavedRegisters];
-  uint64_t saved_fpregisters[kNumberOfCalleeSavedFPRegisters];
-
-  CPURegList register_list = kCalleeSaved;
-  CPURegList fpregister_list = kCalleeSavedFP;
-
-  for (int i = 0; i < kNumberOfCalleeSavedRegisters; i++) {
-    // x31 is not a caller saved register, so no need to specify if we want
-    // the stack or zero.
-    saved_registers[i] = xreg(register_list.PopLowestIndex().code());
-  }
-  for (int i = 0; i < kNumberOfCalleeSavedFPRegisters; i++) {
-    saved_fpregisters[i] =
-        dreg_bits(fpregister_list.PopLowestIndex().code());
-  }
-  int64_t original_stack = sp();
-#endif
-  // Start the simulation!
-  Run();
-#ifdef DEBUG
-  CHECK_EQ(original_stack, sp());
-  // Check that callee-saved registers have been preserved.
-  register_list = kCalleeSaved;
-  fpregister_list = kCalleeSavedFP;
-  for (int i = 0; i < kNumberOfCalleeSavedRegisters; i++) {
-    CHECK_EQ(saved_registers[i], xreg(register_list.PopLowestIndex().code()));
-  }
-  for (int i = 0; i < kNumberOfCalleeSavedFPRegisters; i++) {
-    ASSERT(saved_fpregisters[i] ==
-           dreg_bits(fpregister_list.PopLowestIndex().code()));
-  }
-
-  // Corrupt caller saved register minus the return regiters.
-
-  // In theory x0 to x7 can be used for return values, but V8 only uses x0, x1
-  // for now .
-  register_list = kCallerSaved;
-  register_list.Remove(x0);
-  register_list.Remove(x1);
-
-  // In theory d0 to d7 can be used for return values, but V8 only uses d0
-  // for now .
-  fpregister_list = kCallerSavedFP;
-  fpregister_list.Remove(d0);
-
-  CorruptRegisters(&register_list, kCallerSavedRegisterCorruptionValue);
-  CorruptRegisters(&fpregister_list, kCallerSavedFPRegisterCorruptionValue);
-#endif
-}
-
-
-#ifdef DEBUG
-// The least significant byte of the curruption value holds the corresponding
-// register's code.
-void Simulator::CorruptRegisters(CPURegList* list, uint64_t value) {
-  if (list->type() == CPURegister::kRegister) {
-    while (!list->IsEmpty()) {
-      unsigned code = list->PopLowestIndex().code();
-      set_xreg(code, value | code);
-    }
-  } else {
-    ASSERT(list->type() == CPURegister::kFPRegister);
-    while (!list->IsEmpty()) {
-      unsigned code = list->PopLowestIndex().code();
-      set_dreg_bits(code, value | code);
-    }
-  }
-}
-
-
-void Simulator::CorruptAllCallerSavedCPURegisters() {
-  // Corrupt alters its parameter so copy them first.
-  CPURegList register_list = kCallerSaved;
-  CPURegList fpregister_list = kCallerSavedFP;
-
-  CorruptRegisters(&register_list, kCallerSavedRegisterCorruptionValue);
-  CorruptRegisters(&fpregister_list, kCallerSavedFPRegisterCorruptionValue);
-}
-#endif
-
-
-// Extending the stack by 2 * 64 bits is required for stack alignment purposes.
-uintptr_t Simulator::PushAddress(uintptr_t address) {
-  ASSERT(sizeof(uintptr_t) < 2 * kXRegSize);
-  intptr_t new_sp = sp() - 2 * kXRegSize;
-  uintptr_t* alignment_slot =
-    reinterpret_cast<uintptr_t*>(new_sp + kXRegSize);
-  memcpy(alignment_slot, &kSlotsZapValue, kPointerSize);
-  uintptr_t* stack_slot = reinterpret_cast<uintptr_t*>(new_sp);
-  memcpy(stack_slot, &address, kPointerSize);
-  set_sp(new_sp);
-  return new_sp;
-}
-
-
-uintptr_t Simulator::PopAddress() {
-  intptr_t current_sp = sp();
-  uintptr_t* stack_slot = reinterpret_cast<uintptr_t*>(current_sp);
-  uintptr_t address = *stack_slot;
-  ASSERT(sizeof(uintptr_t) < 2 * kXRegSize);
-  set_sp(current_sp + 2 * kXRegSize);
-  return address;
-}
-
-
-// Returns the limit of the stack area to enable checking for stack overflows.
-uintptr_t Simulator::StackLimit() const {
-  // Leave a safety margin of 1024 bytes to prevent overrunning the stack when
-  // pushing values.
-  return reinterpret_cast<uintptr_t>(stack_limit_) + 1024;
-}
-
-
-Simulator::Simulator(Decoder<DispatchingDecoderVisitor>* decoder,
-                     Isolate* isolate, FILE* stream)
-    : decoder_(decoder),
-      last_debugger_input_(NULL),
-      log_parameters_(NO_PARAM),
-      isolate_(isolate) {
-  // Setup the decoder.
-  decoder_->AppendVisitor(this);
-
-  Init(stream);
-
-  if (FLAG_trace_sim) {
-    decoder_->InsertVisitorBefore(print_disasm_, this);
-    log_parameters_ = LOG_ALL;
-  }
-
-  if (FLAG_log_instruction_stats) {
-    instrument_ = new Instrument(FLAG_log_instruction_file,
-                                 FLAG_log_instruction_period);
-    decoder_->AppendVisitor(instrument_);
-  }
-}
-
-
-Simulator::Simulator()
-    : decoder_(NULL),
-      last_debugger_input_(NULL),
-      log_parameters_(NO_PARAM),
-      isolate_(NULL) {
-  Init(NULL);
-  CHECK(!FLAG_trace_sim && !FLAG_log_instruction_stats);
-}
-
-
-void Simulator::Init(FILE* stream) {
-  ResetState();
-
-  // Allocate and setup the simulator stack.
-  stack_size_ = (FLAG_sim_stack_size * KB) + (2 * stack_protection_size_);
-  stack_ = new byte[stack_size_];
-  stack_limit_ = stack_ + stack_protection_size_;
-  byte* tos = stack_ + stack_size_ - stack_protection_size_;
-  // The stack pointer must be 16 bytes aligned.
-  set_sp(reinterpret_cast<int64_t>(tos) & ~0xfUL);
-
-  stream_ = stream;
-  print_disasm_ = new PrintDisassembler(stream_);
-
-  // The debugger needs to disassemble code without the simulator executing an
-  // instruction, so we create a dedicated decoder.
-  disassembler_decoder_ = new Decoder<DispatchingDecoderVisitor>();
-  disassembler_decoder_->AppendVisitor(print_disasm_);
-}
-
-
-void Simulator::ResetState() {
-  // Reset the system registers.
-  nzcv_ = SimSystemRegister::DefaultValueFor(NZCV);
-  fpcr_ = SimSystemRegister::DefaultValueFor(FPCR);
-
-  // Reset registers to 0.
-  pc_ = NULL;
-  for (unsigned i = 0; i < kNumberOfRegisters; i++) {
-    set_xreg(i, 0xbadbeef);
-  }
-  for (unsigned i = 0; i < kNumberOfFPRegisters; i++) {
-    // Set FP registers to a value that is NaN in both 32-bit and 64-bit FP.
-    set_dreg_bits(i, 0x7ff000007f800001UL);
-  }
-  // Returning to address 0 exits the Simulator.
-  set_lr(kEndOfSimAddress);
-
-  // Reset debug helpers.
-  breakpoints_.empty();
-  break_on_next_= false;
-}
-
-
-Simulator::~Simulator() {
-  delete[] stack_;
-  if (FLAG_log_instruction_stats) {
-    delete instrument_;
-  }
-  delete disassembler_decoder_;
-  delete print_disasm_;
-  DeleteArray(last_debugger_input_);
-  delete decoder_;
-}
-
-
-void Simulator::Run() {
-  pc_modified_ = false;
-  while (pc_ != kEndOfSimAddress) {
-    ExecuteInstruction();
-  }
-}
-
-
-void Simulator::RunFrom(Instruction* start) {
-  set_pc(start);
-  Run();
-}
-
-
-// When the generated code calls an external reference we need to catch that in
-// the simulator.  The external reference will be a function compiled for the
-// host architecture.  We need to call that function instead of trying to
-// execute it with the simulator.  We do that by redirecting the external
-// reference to a svc (Supervisor Call) instruction that is handled by
-// the simulator.  We write the original destination of the jump just at a known
-// offset from the svc instruction so the simulator knows what to call.
-class Redirection {
- public:
-  Redirection(void* external_function, ExternalReference::Type type)
-      : external_function_(external_function),
-        type_(type),
-        next_(NULL) {
-    redirect_call_.SetInstructionBits(
-        HLT | Assembler::ImmException(kImmExceptionIsRedirectedCall));
-    Isolate* isolate = Isolate::Current();
-    next_ = isolate->simulator_redirection();
-    // TODO(all): Simulator flush I cache
-    isolate->set_simulator_redirection(this);
-  }
-
-  void* address_of_redirect_call() {
-    return reinterpret_cast<void*>(&redirect_call_);
-  }
-
-  template <typename T>
-  T external_function() { return reinterpret_cast<T>(external_function_); }
-
-  ExternalReference::Type type() { return type_; }
-
-  static Redirection* Get(void* external_function,
-                          ExternalReference::Type type) {
-    Isolate* isolate = Isolate::Current();
-    Redirection* current = isolate->simulator_redirection();
-    for (; current != NULL; current = current->next_) {
-      if (current->external_function_ == external_function) {
-        ASSERT_EQ(current->type(), type);
-        return current;
-      }
-    }
-    return new Redirection(external_function, type);
-  }
-
-  static Redirection* FromHltInstruction(Instruction* redirect_call) {
-    char* addr_of_hlt = reinterpret_cast<char*>(redirect_call);
-    char* addr_of_redirection =
-        addr_of_hlt - OFFSET_OF(Redirection, redirect_call_);
-    return reinterpret_cast<Redirection*>(addr_of_redirection);
-  }
-
-  static void* ReverseRedirection(int64_t reg) {
-    Redirection* redirection =
-        FromHltInstruction(reinterpret_cast<Instruction*>(reg));
-    return redirection->external_function<void*>();
-  }
-
- private:
-  void* external_function_;
-  Instruction redirect_call_;
-  ExternalReference::Type type_;
-  Redirection* next_;
-};
-
-
-// Calls into the V8 runtime are based on this very simple interface.
-// Note: To be able to return two values from some calls the code in runtime.cc
-// uses the ObjectPair structure.
-// The simulator assumes all runtime calls return two 64-bits values. If they
-// don't, register x1 is clobbered. This is fine because x1 is caller-saved.
-struct ObjectPair {
-  int64_t res0;
-  int64_t res1;
-};
-
-
-typedef ObjectPair (*SimulatorRuntimeCall)(int64_t arg0,
-                                           int64_t arg1,
-                                           int64_t arg2,
-                                           int64_t arg3,
-                                           int64_t arg4,
-                                           int64_t arg5,
-                                           int64_t arg6,
-                                           int64_t arg7);
-
-typedef int64_t (*SimulatorRuntimeCompareCall)(double arg1, double arg2);
-typedef double (*SimulatorRuntimeFPFPCall)(double arg1, double arg2);
-typedef double (*SimulatorRuntimeFPCall)(double arg1);
-typedef double (*SimulatorRuntimeFPIntCall)(double arg1, int32_t arg2);
-
-// This signature supports direct call in to API function native callback
-// (refer to InvocationCallback in v8.h).
-typedef void (*SimulatorRuntimeDirectApiCall)(int64_t arg0);
-typedef void (*SimulatorRuntimeProfilingApiCall)(int64_t arg0, void* arg1);
-
-// This signature supports direct call to accessor getter callback.
-typedef void (*SimulatorRuntimeDirectGetterCall)(int64_t arg0, int64_t arg1);
-typedef void (*SimulatorRuntimeProfilingGetterCall)(int64_t arg0, int64_t arg1,
-                                                    void* arg2);
-
-void Simulator::DoRuntimeCall(Instruction* instr) {
-  Redirection* redirection = Redirection::FromHltInstruction(instr);
-
-  // The called C code might itself call simulated code, so any
-  // caller-saved registers (including lr) could still be clobbered by a
-  // redirected call.
-  Instruction* return_address = lr();
-
-  int64_t external = redirection->external_function<int64_t>();
-
-  TraceSim("Call to host function at %p\n",
-           redirection->external_function<void*>());
-
-  // SP must be 16-byte-aligned at the call interface.
-  bool stack_alignment_exception = ((sp() & 0xf) != 0);
-  if (stack_alignment_exception) {
-    TraceSim("  with unaligned stack 0x%016" PRIx64 ".\n", sp());
-    FATAL("ALIGNMENT EXCEPTION");
-  }
-
-  switch (redirection->type()) {
-    default:
-      TraceSim("Type: Unknown.\n");
-      UNREACHABLE();
-      break;
-
-    case ExternalReference::BUILTIN_CALL: {
-      // MaybeObject* f(v8::internal::Arguments).
-      TraceSim("Type: BUILTIN_CALL\n");
-      SimulatorRuntimeCall target =
-        reinterpret_cast<SimulatorRuntimeCall>(external);
-
-      // We don't know how many arguments are being passed, but we can
-      // pass 8 without touching the stack. They will be ignored by the
-      // host function if they aren't used.
-      TraceSim("Arguments: "
-               "0x%016" PRIx64 ", 0x%016" PRIx64 ", "
-               "0x%016" PRIx64 ", 0x%016" PRIx64 ", "
-               "0x%016" PRIx64 ", 0x%016" PRIx64 ", "
-               "0x%016" PRIx64 ", 0x%016" PRIx64,
-               xreg(0), xreg(1), xreg(2), xreg(3),
-               xreg(4), xreg(5), xreg(6), xreg(7));
-      ObjectPair result = target(xreg(0), xreg(1), xreg(2), xreg(3),
-                                 xreg(4), xreg(5), xreg(6), xreg(7));
-      TraceSim("Returned: {0x%" PRIx64 ", 0x%" PRIx64 "}\n",
-               result.res0, result.res1);
-#ifdef DEBUG
-      CorruptAllCallerSavedCPURegisters();
-#endif
-      set_xreg(0, result.res0);
-      set_xreg(1, result.res1);
-      break;
-    }
-
-    case ExternalReference::DIRECT_API_CALL: {
-      // void f(v8::FunctionCallbackInfo&)
-      TraceSim("Type: DIRECT_API_CALL\n");
-      SimulatorRuntimeDirectApiCall target =
-        reinterpret_cast<SimulatorRuntimeDirectApiCall>(external);
-      TraceSim("Arguments: 0x%016" PRIx64 "\n", xreg(0));
-      target(xreg(0));
-      TraceSim("No return value.");
-#ifdef DEBUG
-      CorruptAllCallerSavedCPURegisters();
-#endif
-      break;
-    }
-
-    case ExternalReference::BUILTIN_COMPARE_CALL: {
-      // int f(double, double)
-      TraceSim("Type: BUILTIN_COMPARE_CALL\n");
-      SimulatorRuntimeCompareCall target =
-        reinterpret_cast<SimulatorRuntimeCompareCall>(external);
-      TraceSim("Arguments: %f, %f\n", dreg(0), dreg(1));
-      int64_t result = target(dreg(0), dreg(1));
-      TraceSim("Returned: %" PRId64 "\n", result);
-#ifdef DEBUG
-      CorruptAllCallerSavedCPURegisters();
-#endif
-      set_xreg(0, result);
-      break;
-    }
-
-    case ExternalReference::BUILTIN_FP_CALL: {
-      // double f(double)
-      TraceSim("Type: BUILTIN_FP_CALL\n");
-      SimulatorRuntimeFPCall target =
-        reinterpret_cast<SimulatorRuntimeFPCall>(external);
-      TraceSim("Argument: %f\n", dreg(0));
-      double result = target(dreg(0));
-      TraceSim("Returned: %f\n", result);
-#ifdef DEBUG
-      CorruptAllCallerSavedCPURegisters();
-#endif
-      set_dreg(0, result);
-      break;
-    }
-
-    case ExternalReference::BUILTIN_FP_FP_CALL: {
-      // double f(double, double)
-      TraceSim("Type: BUILTIN_FP_FP_CALL\n");
-      SimulatorRuntimeFPFPCall target =
-        reinterpret_cast<SimulatorRuntimeFPFPCall>(external);
-      TraceSim("Arguments: %f, %f\n", dreg(0), dreg(1));
-      double result = target(dreg(0), dreg(1));
-      TraceSim("Returned: %f\n", result);
-#ifdef DEBUG
-      CorruptAllCallerSavedCPURegisters();
-#endif
-      set_dreg(0, result);
-      break;
-    }
-
-    case ExternalReference::BUILTIN_FP_INT_CALL: {
-      // double f(double, int)
-      TraceSim("Type: BUILTIN_FP_INT_CALL\n");
-      SimulatorRuntimeFPIntCall target =
-        reinterpret_cast<SimulatorRuntimeFPIntCall>(external);
-      TraceSim("Arguments: %f, %d\n", dreg(0), wreg(0));
-      double result = target(dreg(0), wreg(0));
-      TraceSim("Returned: %f\n", result);
-#ifdef DEBUG
-      CorruptAllCallerSavedCPURegisters();
-#endif
-      set_dreg(0, result);
-      break;
-    }
-
-    case ExternalReference::DIRECT_GETTER_CALL: {
-      // void f(Local<String> property, PropertyCallbackInfo& info)
-      TraceSim("Type: DIRECT_GETTER_CALL\n");
-      SimulatorRuntimeDirectGetterCall target =
-        reinterpret_cast<SimulatorRuntimeDirectGetterCall>(external);
-      TraceSim("Arguments: 0x%016" PRIx64 ", 0x%016" PRIx64 "\n",
-               xreg(0), xreg(1));
-      target(xreg(0), xreg(1));
-      TraceSim("No return value.");
-#ifdef DEBUG
-      CorruptAllCallerSavedCPURegisters();
-#endif
-      break;
-    }
-
-    case ExternalReference::PROFILING_API_CALL: {
-      // void f(v8::FunctionCallbackInfo&, v8::FunctionCallback)
-      TraceSim("Type: PROFILING_API_CALL\n");
-      SimulatorRuntimeProfilingApiCall target =
-        reinterpret_cast<SimulatorRuntimeProfilingApiCall>(external);
-      void* arg1 = Redirection::ReverseRedirection(xreg(1));
-      TraceSim("Arguments: 0x%016" PRIx64 ", %p\n", xreg(0), arg1);
-      target(xreg(0), arg1);
-      TraceSim("No return value.");
-#ifdef DEBUG
-      CorruptAllCallerSavedCPURegisters();
-#endif
-      break;
-    }
-
-    case ExternalReference::PROFILING_GETTER_CALL: {
-      // void f(Local<String> property, PropertyCallbackInfo& info,
-      //        AccessorGetterCallback callback)
-      TraceSim("Type: PROFILING_GETTER_CALL\n");
-      SimulatorRuntimeProfilingGetterCall target =
-        reinterpret_cast<SimulatorRuntimeProfilingGetterCall>(
-            external);
-      void* arg2 = Redirection::ReverseRedirection(xreg(2));
-      TraceSim("Arguments: 0x%016" PRIx64 ", 0x%016" PRIx64 ", %p\n",
-               xreg(0), xreg(1), arg2);
-      target(xreg(0), xreg(1), arg2);
-      TraceSim("No return value.");
-#ifdef DEBUG
-      CorruptAllCallerSavedCPURegisters();
-#endif
-      break;
-    }
-  }
-
-  set_lr(return_address);
-  set_pc(return_address);
-}
-
-
-void* Simulator::RedirectExternalReference(void* external_function,
-                                           ExternalReference::Type type) {
-  Redirection* redirection = Redirection::Get(external_function, type);
-  return redirection->address_of_redirect_call();
-}
-
-
-const char* Simulator::xreg_names[] = {
-"x0",  "x1",  "x2",  "x3",  "x4",  "x5",  "x6",  "x7",
-"x8",  "x9",  "x10", "x11", "x12", "x13", "x14", "x15",
-"ip0", "ip1", "x18", "x19", "x20", "x21", "x22", "x23",
-"x24", "x25", "x26", "cp", "jssp", "fp", "lr",  "xzr", "csp"};
-
-const char* Simulator::wreg_names[] = {
-"w0",  "w1",  "w2",  "w3",  "w4",  "w5",  "w6",  "w7",
-"w8",  "w9",  "w10", "w11", "w12", "w13", "w14", "w15",
-"w16", "w17", "w18", "w19", "w20", "w21", "w22", "w23",
-"w24", "w25", "w26", "wcp", "wjssp", "wfp", "wlr", "wzr", "wcsp"};
-
-const char* Simulator::sreg_names[] = {
-"s0",  "s1",  "s2",  "s3",  "s4",  "s5",  "s6",  "s7",
-"s8",  "s9",  "s10", "s11", "s12", "s13", "s14", "s15",
-"s16", "s17", "s18", "s19", "s20", "s21", "s22", "s23",
-"s24", "s25", "s26", "s27", "s28", "s29", "s30", "s31"};
-
-const char* Simulator::dreg_names[] = {
-"d0",  "d1",  "d2",  "d3",  "d4",  "d5",  "d6",  "d7",
-"d8",  "d9",  "d10", "d11", "d12", "d13", "d14", "d15",
-"d16", "d17", "d18", "d19", "d20", "d21", "d22", "d23",
-"d24", "d25", "d26", "d27", "d28", "d29", "d30", "d31"};
-
-const char* Simulator::vreg_names[] = {
-"v0",  "v1",  "v2",  "v3",  "v4",  "v5",  "v6",  "v7",
-"v8",  "v9",  "v10", "v11", "v12", "v13", "v14", "v15",
-"v16", "v17", "v18", "v19", "v20", "v21", "v22", "v23",
-"v24", "v25", "v26", "v27", "v28", "v29", "v30", "v31"};
-
-
-const char* Simulator::WRegNameForCode(unsigned code, Reg31Mode mode) {
-  ASSERT(code < kNumberOfRegisters);
-  // If the code represents the stack pointer, index the name after zr.
-  if ((code == kZeroRegCode) && (mode == Reg31IsStackPointer)) {
-    code = kZeroRegCode + 1;
-  }
-  return wreg_names[code];
-}
-
-
-const char* Simulator::XRegNameForCode(unsigned code, Reg31Mode mode) {
-  ASSERT(code < kNumberOfRegisters);
-  // If the code represents the stack pointer, index the name after zr.
-  if ((code == kZeroRegCode) && (mode == Reg31IsStackPointer)) {
-    code = kZeroRegCode + 1;
-  }
-  return xreg_names[code];
-}
-
-
-const char* Simulator::SRegNameForCode(unsigned code) {
-  ASSERT(code < kNumberOfFPRegisters);
-  return sreg_names[code];
-}
-
-
-const char* Simulator::DRegNameForCode(unsigned code) {
-  ASSERT(code < kNumberOfFPRegisters);
-  return dreg_names[code];
-}
-
-
-const char* Simulator::VRegNameForCode(unsigned code) {
-  ASSERT(code < kNumberOfFPRegisters);
-  return vreg_names[code];
-}
-
-
-int Simulator::CodeFromName(const char* name) {
-  for (unsigned i = 0; i < kNumberOfRegisters; i++) {
-    if ((strcmp(xreg_names[i], name) == 0) ||
-        (strcmp(wreg_names[i], name) == 0)) {
-      return i;
-    }
-  }
-  for (unsigned i = 0; i < kNumberOfFPRegisters; i++) {
-    if ((strcmp(vreg_names[i], name) == 0) ||
-        (strcmp(dreg_names[i], name) == 0) ||
-        (strcmp(sreg_names[i], name) == 0)) {
-      return i;
-    }
-  }
-  if ((strcmp("csp", name) == 0) || (strcmp("wcsp", name) == 0)) {
-    return kSPRegInternalCode;
-  }
-  return -1;
-}
-
-
-// Helpers ---------------------------------------------------------------------
-int64_t Simulator::AddWithCarry(unsigned reg_size,
-                                bool set_flags,
-                                int64_t src1,
-                                int64_t src2,
-                                int64_t carry_in) {
-  ASSERT((carry_in == 0) || (carry_in == 1));
-  ASSERT((reg_size == kXRegSizeInBits) || (reg_size == kWRegSizeInBits));
-
-  uint64_t u1, u2;
-  int64_t result;
-  int64_t signed_sum = src1 + src2 + carry_in;
-
-  bool N, Z, C, V;
-
-  if (reg_size == kWRegSizeInBits) {
-    u1 = static_cast<uint64_t>(src1) & kWRegMask;
-    u2 = static_cast<uint64_t>(src2) & kWRegMask;
-
-    result = signed_sum & kWRegMask;
-    // Compute the C flag by comparing the sum to the max unsigned integer.
-    C = ((kWMaxUInt - u1) < (u2 + carry_in)) ||
-        ((kWMaxUInt - u1 - carry_in) < u2);
-    // Overflow iff the sign bit is the same for the two inputs and different
-    // for the result.
-    int64_t s_src1 = src1 << (kXRegSizeInBits - kWRegSizeInBits);
-    int64_t s_src2 = src2 << (kXRegSizeInBits - kWRegSizeInBits);
-    int64_t s_result = result << (kXRegSizeInBits - kWRegSizeInBits);
-    V = ((s_src1 ^ s_src2) >= 0) && ((s_src1 ^ s_result) < 0);
-
-  } else {
-    u1 = static_cast<uint64_t>(src1);
-    u2 = static_cast<uint64_t>(src2);
-
-    result = signed_sum;
-    // Compute the C flag by comparing the sum to the max unsigned integer.
-    C = ((kXMaxUInt - u1) < (u2 + carry_in)) ||
-        ((kXMaxUInt - u1 - carry_in) < u2);
-    // Overflow iff the sign bit is the same for the two inputs and different
-    // for the result.
-    V = ((src1 ^ src2) >= 0) && ((src1 ^ result) < 0);
-  }
-
-  N = CalcNFlag(result, reg_size);
-  Z = CalcZFlag(result);
-
-  if (set_flags) {
-    nzcv().SetN(N);
-    nzcv().SetZ(Z);
-    nzcv().SetC(C);
-    nzcv().SetV(V);
-  }
-  return result;
-}
-
-
-int64_t Simulator::ShiftOperand(unsigned reg_size,
-                                int64_t value,
-                                Shift shift_type,
-                                unsigned amount) {
-  if (amount == 0) {
-    return value;
-  }
-  int64_t mask = reg_size == kXRegSizeInBits ? kXRegMask : kWRegMask;
-  switch (shift_type) {
-    case LSL:
-      return (value << amount) & mask;
-    case LSR:
-      return static_cast<uint64_t>(value) >> amount;
-    case ASR: {
-      // Shift used to restore the sign.
-      unsigned s_shift = kXRegSizeInBits - reg_size;
-      // Value with its sign restored.
-      int64_t s_value = (value << s_shift) >> s_shift;
-      return (s_value >> amount) & mask;
-    }
-    case ROR: {
-      if (reg_size == kWRegSizeInBits) {
-        value &= kWRegMask;
-      }
-      return (static_cast<uint64_t>(value) >> amount) |
-             ((value & ((1L << amount) - 1L)) << (reg_size - amount));
-    }
-    default:
-      UNIMPLEMENTED();
-      return 0;
-  }
-}
-
-
-int64_t Simulator::ExtendValue(unsigned reg_size,
-                               int64_t value,
-                               Extend extend_type,
-                               unsigned left_shift) {
-  switch (extend_type) {
-    case UXTB:
-      value &= kByteMask;
-      break;
-    case UXTH:
-      value &= kHalfWordMask;
-      break;
-    case UXTW:
-      value &= kWordMask;
-      break;
-    case SXTB:
-      value = (value << 56) >> 56;
-      break;
-    case SXTH:
-      value = (value << 48) >> 48;
-      break;
-    case SXTW:
-      value = (value << 32) >> 32;
-      break;
-    case UXTX:
-    case SXTX:
-      break;
-    default:
-      UNREACHABLE();
-  }
-  int64_t mask = (reg_size == kXRegSizeInBits) ? kXRegMask : kWRegMask;
-  return (value << left_shift) & mask;
-}
-
-
-template<> double Simulator::FPDefaultNaN<double>() const {
-  return kFP64DefaultNaN;
-}
-
-
-template<> float Simulator::FPDefaultNaN<float>() const {
-  return kFP32DefaultNaN;
-}
-
-
-void Simulator::FPCompare(double val0, double val1) {
-  AssertSupportedFPCR();
-
-  // TODO(jbramley): This assumes that the C++ implementation handles
-  // comparisons in the way that we expect (as per AssertSupportedFPCR()).
-  if ((std::isnan(val0) != 0) || (std::isnan(val1) != 0)) {
-    nzcv().SetRawValue(FPUnorderedFlag);
-  } else if (val0 < val1) {
-    nzcv().SetRawValue(FPLessThanFlag);
-  } else if (val0 > val1) {
-    nzcv().SetRawValue(FPGreaterThanFlag);
-  } else if (val0 == val1) {
-    nzcv().SetRawValue(FPEqualFlag);
-  } else {
-    UNREACHABLE();
-  }
-}
-
-
-void Simulator::SetBreakpoint(Instruction* location) {
-  for (unsigned i = 0; i < breakpoints_.size(); i++) {
-    if (breakpoints_.at(i).location == location) {
-      PrintF("Existing breakpoint at %p was %s\n",
-             reinterpret_cast<void*>(location),
-             breakpoints_.at(i).enabled ? "disabled" : "enabled");
-      breakpoints_.at(i).enabled = !breakpoints_.at(i).enabled;
-      return;
-    }
-  }
-  Breakpoint new_breakpoint = {location, true};
-  breakpoints_.push_back(new_breakpoint);
-  PrintF("Set a breakpoint at %p\n", reinterpret_cast<void*>(location));
-}
-
-
-void Simulator::ListBreakpoints() {
-  PrintF("Breakpoints:\n");
-  for (unsigned i = 0; i < breakpoints_.size(); i++) {
-    PrintF("%p  : %s\n",
-           reinterpret_cast<void*>(breakpoints_.at(i).location),
-           breakpoints_.at(i).enabled ? "enabled" : "disabled");
-  }
-}
-
-
-void Simulator::CheckBreakpoints() {
-  bool hit_a_breakpoint = false;
-  for (unsigned i = 0; i < breakpoints_.size(); i++) {
-    if ((breakpoints_.at(i).location == pc_) &&
-        breakpoints_.at(i).enabled) {
-      hit_a_breakpoint = true;
-      // Disable this breakpoint.
-      breakpoints_.at(i).enabled = false;
-    }
-  }
-  if (hit_a_breakpoint) {
-    PrintF("Hit and disabled a breakpoint at %p.\n",
-           reinterpret_cast<void*>(pc_));
-    Debug();
-  }
-}
-
-
-void Simulator::CheckBreakNext() {
-  // If the current instruction is a BL, insert a breakpoint just after it.
-  if (break_on_next_ && pc_->IsBranchAndLinkToRegister()) {
-    SetBreakpoint(pc_->following());
-    break_on_next_ = false;
-  }
-}
-
-
-void Simulator::PrintInstructionsAt(Instruction* start, uint64_t count) {
-  Instruction* end = start->InstructionAtOffset(count * kInstructionSize);
-  for (Instruction* pc = start; pc < end; pc = pc->following()) {
-    disassembler_decoder_->Decode(pc);
-  }
-}
-
-
-void Simulator::PrintSystemRegisters(bool print_all) {
-  static bool first_run = true;
-
-  static SimSystemRegister last_nzcv;
-  if (print_all || first_run || (last_nzcv.RawValue() != nzcv().RawValue())) {
-    fprintf(stream_, "# %sFLAGS: %sN:%d Z:%d C:%d V:%d%s\n",
-            clr_flag_name,
-            clr_flag_value,
-            nzcv().N(), nzcv().Z(), nzcv().C(), nzcv().V(),
-            clr_normal);
-  }
-  last_nzcv = nzcv();
-
-  static SimSystemRegister last_fpcr;
-  if (print_all || first_run || (last_fpcr.RawValue() != fpcr().RawValue())) {
-    static const char * rmode[] = {
-      "0b00 (Round to Nearest)",
-      "0b01 (Round towards Plus Infinity)",
-      "0b10 (Round towards Minus Infinity)",
-      "0b11 (Round towards Zero)"
-    };
-    ASSERT(fpcr().RMode() <= (sizeof(rmode) / sizeof(rmode[0])));
-    fprintf(stream_, "# %sFPCR: %sAHP:%d DN:%d FZ:%d RMode:%s%s\n",
-            clr_flag_name,
-            clr_flag_value,
-            fpcr().AHP(), fpcr().DN(), fpcr().FZ(), rmode[fpcr().RMode()],
-            clr_normal);
-  }
-  last_fpcr = fpcr();
-
-  first_run = false;
-}
-
-
-void Simulator::PrintRegisters(bool print_all_regs) {
-  static bool first_run = true;
-  static int64_t last_regs[kNumberOfRegisters];
-
-  for (unsigned i = 0; i < kNumberOfRegisters; i++) {
-    if (print_all_regs || first_run ||
-        (last_regs[i] != xreg(i, Reg31IsStackPointer))) {
-      fprintf(stream_,
-              "# %s%4s:%s 0x%016" PRIx64 "%s\n",
-              clr_reg_name,
-              XRegNameForCode(i, Reg31IsStackPointer),
-              clr_reg_value,
-              xreg(i, Reg31IsStackPointer),
-              clr_normal);
-    }
-    // Cache the new register value so the next run can detect any changes.
-    last_regs[i] = xreg(i, Reg31IsStackPointer);
-  }
-  first_run = false;
-}
-
-
-void Simulator::PrintFPRegisters(bool print_all_regs) {
-  static bool first_run = true;
-  static uint64_t last_regs[kNumberOfFPRegisters];
-
-  // Print as many rows of registers as necessary, keeping each individual
-  // register in the same column each time (to make it easy to visually scan
-  // for changes).
-  for (unsigned i = 0; i < kNumberOfFPRegisters; i++) {
-    if (print_all_regs || first_run || (last_regs[i] != dreg_bits(i))) {
-      fprintf(stream_,
-              "# %s %4s:%s 0x%016" PRIx64 "%s (%s%s:%s %g%s %s:%s %g%s)\n",
-              clr_fpreg_name,
-              VRegNameForCode(i),
-              clr_fpreg_value,
-              dreg_bits(i),
-              clr_normal,
-              clr_fpreg_name,
-              DRegNameForCode(i),
-              clr_fpreg_value,
-              dreg(i),
-              clr_fpreg_name,
-              SRegNameForCode(i),
-              clr_fpreg_value,
-              sreg(i),
-              clr_normal);
-    }
-    // Cache the new register value so the next run can detect any changes.
-    last_regs[i] = dreg_bits(i);
-  }
-  first_run = false;
-}
-
-
-void Simulator::PrintProcessorState() {
-  PrintSystemRegisters();
-  PrintRegisters();
-  PrintFPRegisters();
-}
-
-
-void Simulator::PrintWrite(uint8_t* address,
-                           uint64_t value,
-                           unsigned num_bytes) {
-  // The template is "# value -> address". The template is not directly used
-  // in the printf since compilers tend to struggle with the parametrized
-  // width (%0*).
-  const char* format = "# %s0x%0*" PRIx64 "%s -> %s0x%016" PRIx64 "%s\n";
-  fprintf(stream_,
-          format,
-          clr_memory_value,
-          num_bytes * 2,  // The width in hexa characters.
-          value,
-          clr_normal,
-          clr_memory_address,
-          address,
-          clr_normal);
-}
-
-
-// Visitors---------------------------------------------------------------------
-
-void Simulator::VisitUnimplemented(Instruction* instr) {
-  fprintf(stream_, "Unimplemented instruction at %p: 0x%08" PRIx32 "\n",
-          reinterpret_cast<void*>(instr), instr->InstructionBits());
-  UNIMPLEMENTED();
-}
-
-
-void Simulator::VisitUnallocated(Instruction* instr) {
-  fprintf(stream_, "Unallocated instruction at %p: 0x%08" PRIx32 "\n",
-          reinterpret_cast<void*>(instr), instr->InstructionBits());
-  UNIMPLEMENTED();
-}
-
-
-void Simulator::VisitPCRelAddressing(Instruction* instr) {
-  switch (instr->Mask(PCRelAddressingMask)) {
-    case ADR:
-      set_reg(instr->Rd(), instr->ImmPCOffsetTarget());
-      break;
-    case ADRP:  // Not implemented in the assembler.
-      UNIMPLEMENTED();
-      break;
-    default:
-      UNREACHABLE();
-      break;
-  }
-}
-
-
-void Simulator::VisitUnconditionalBranch(Instruction* instr) {
-  switch (instr->Mask(UnconditionalBranchMask)) {
-    case BL:
-      set_lr(instr->following());
-      // Fall through.
-    case B:
-      set_pc(instr->ImmPCOffsetTarget());
-      break;
-    default:
-      UNREACHABLE();
-  }
-}
-
-
-void Simulator::VisitConditionalBranch(Instruction* instr) {
-  ASSERT(instr->Mask(ConditionalBranchMask) == B_cond);
-  if (ConditionPassed(static_cast<Condition>(instr->ConditionBranch()))) {
-    set_pc(instr->ImmPCOffsetTarget());
-  }
-}
-
-
-void Simulator::VisitUnconditionalBranchToRegister(Instruction* instr) {
-  Instruction* target = reg<Instruction*>(instr->Rn());
-  switch (instr->Mask(UnconditionalBranchToRegisterMask)) {
-    case BLR: {
-      set_lr(instr->following());
-      if (instr->Rn() == 31) {
-        // BLR XZR is used as a guard for the constant pool. We should never hit
-        // this, but if we do trap to allow debugging.
-        Debug();
-      }
-      // Fall through.
-    }
-    case BR:
-    case RET: set_pc(target); break;
-    default: UNIMPLEMENTED();
-  }
-}
-
-
-void Simulator::VisitTestBranch(Instruction* instr) {
-  unsigned bit_pos = (instr->ImmTestBranchBit5() << 5) |
-                     instr->ImmTestBranchBit40();
-  bool take_branch = ((xreg(instr->Rt()) & (1UL << bit_pos)) == 0);
-  switch (instr->Mask(TestBranchMask)) {
-    case TBZ: break;
-    case TBNZ: take_branch = !take_branch; break;
-    default: UNIMPLEMENTED();
-  }
-  if (take_branch) {
-    set_pc(instr->ImmPCOffsetTarget());
-  }
-}
-
-
-void Simulator::VisitCompareBranch(Instruction* instr) {
-  unsigned rt = instr->Rt();
-  bool take_branch = false;
-  switch (instr->Mask(CompareBranchMask)) {
-    case CBZ_w: take_branch = (wreg(rt) == 0); break;
-    case CBZ_x: take_branch = (xreg(rt) == 0); break;
-    case CBNZ_w: take_branch = (wreg(rt) != 0); break;
-    case CBNZ_x: take_branch = (xreg(rt) != 0); break;
-    default: UNIMPLEMENTED();
-  }
-  if (take_branch) {
-    set_pc(instr->ImmPCOffsetTarget());
-  }
-}
-
-
-void Simulator::AddSubHelper(Instruction* instr, int64_t op2) {
-  unsigned reg_size = instr->SixtyFourBits() ? kXRegSizeInBits
-                                             : kWRegSizeInBits;
-  bool set_flags = instr->FlagsUpdate();
-  int64_t new_val = 0;
-  Instr operation = instr->Mask(AddSubOpMask);
-
-  switch (operation) {
-    case ADD:
-    case ADDS: {
-      new_val = AddWithCarry(reg_size,
-                             set_flags,
-                             reg(reg_size, instr->Rn(), instr->RnMode()),
-                             op2);
-      break;
-    }
-    case SUB:
-    case SUBS: {
-      new_val = AddWithCarry(reg_size,
-                             set_flags,
-                             reg(reg_size, instr->Rn(), instr->RnMode()),
-                             ~op2,
-                             1);
-      break;
-    }
-    default: UNREACHABLE();
-  }
-
-  set_reg(reg_size, instr->Rd(), new_val, instr->RdMode());
-}
-
-
-void Simulator::VisitAddSubShifted(Instruction* instr) {
-  unsigned reg_size = instr->SixtyFourBits() ? kXRegSizeInBits
-                                             : kWRegSizeInBits;
-  int64_t op2 = ShiftOperand(reg_size,
-                             reg(reg_size, instr->Rm()),
-                             static_cast<Shift>(instr->ShiftDP()),
-                             instr->ImmDPShift());
-  AddSubHelper(instr, op2);
-}
-
-
-void Simulator::VisitAddSubImmediate(Instruction* instr) {
-  int64_t op2 = instr->ImmAddSub() << ((instr->ShiftAddSub() == 1) ? 12 : 0);
-  AddSubHelper(instr, op2);
-}
-
-
-void Simulator::VisitAddSubExtended(Instruction* instr) {
-  unsigned reg_size = instr->SixtyFourBits() ? kXRegSizeInBits
-                                             : kWRegSizeInBits;
-  int64_t op2 = ExtendValue(reg_size,
-                            reg(reg_size, instr->Rm()),
-                            static_cast<Extend>(instr->ExtendMode()),
-                            instr->ImmExtendShift());
-  AddSubHelper(instr, op2);
-}
-
-
-void Simulator::VisitAddSubWithCarry(Instruction* instr) {
-  unsigned reg_size = instr->SixtyFourBits() ? kXRegSizeInBits
-                                             : kWRegSizeInBits;
-  int64_t op2 = reg(reg_size, instr->Rm());
-  int64_t new_val;
-
-  if ((instr->Mask(AddSubOpMask) == SUB) || instr->Mask(AddSubOpMask) == SUBS) {
-    op2 = ~op2;
-  }
-
-  new_val = AddWithCarry(reg_size,
-                         instr->FlagsUpdate(),
-                         reg(reg_size, instr->Rn()),
-                         op2,
-                         nzcv().C());
-
-  set_reg(reg_size, instr->Rd(), new_val);
-}
-
-
-void Simulator::VisitLogicalShifted(Instruction* instr) {
-  unsigned reg_size = instr->SixtyFourBits() ? kXRegSizeInBits
-                                             : kWRegSizeInBits;
-  Shift shift_type = static_cast<Shift>(instr->ShiftDP());
-  unsigned shift_amount = instr->ImmDPShift();
-  int64_t op2 = ShiftOperand(reg_size, reg(reg_size, instr->Rm()), shift_type,
-                             shift_amount);
-  if (instr->Mask(NOT) == NOT) {
-    op2 = ~op2;
-  }
-  LogicalHelper(instr, op2);
-}
-
-
-void Simulator::VisitLogicalImmediate(Instruction* instr) {
-  LogicalHelper(instr, instr->ImmLogical());
-}
-
-
-void Simulator::LogicalHelper(Instruction* instr, int64_t op2) {
-  unsigned reg_size = instr->SixtyFourBits() ? kXRegSizeInBits
-                                             : kWRegSizeInBits;
-  int64_t op1 = reg(reg_size, instr->Rn());
-  int64_t result = 0;
-  bool update_flags = false;
-
-  // Switch on the logical operation, stripping out the NOT bit, as it has a
-  // different meaning for logical immediate instructions.
-  switch (instr->Mask(LogicalOpMask & ~NOT)) {
-    case ANDS: update_flags = true;  // Fall through.
-    case AND: result = op1 & op2; break;
-    case ORR: result = op1 | op2; break;
-    case EOR: result = op1 ^ op2; break;
-    default:
-      UNIMPLEMENTED();
-  }
-
-  if (update_flags) {
-    nzcv().SetN(CalcNFlag(result, reg_size));
-    nzcv().SetZ(CalcZFlag(result));
-    nzcv().SetC(0);
-    nzcv().SetV(0);
-  }
-
-  set_reg(reg_size, instr->Rd(), result, instr->RdMode());
-}
-
-
-void Simulator::VisitConditionalCompareRegister(Instruction* instr) {
-  unsigned reg_size = instr->SixtyFourBits() ? kXRegSizeInBits
-                                             : kWRegSizeInBits;
-  ConditionalCompareHelper(instr, reg(reg_size, instr->Rm()));
-}
-
-
-void Simulator::VisitConditionalCompareImmediate(Instruction* instr) {
-  ConditionalCompareHelper(instr, instr->ImmCondCmp());
-}
-
-
-void Simulator::ConditionalCompareHelper(Instruction* instr, int64_t op2) {
-  unsigned reg_size = instr->SixtyFourBits() ? kXRegSizeInBits
-                                             : kWRegSizeInBits;
-  int64_t op1 = reg(reg_size, instr->Rn());
-
-  if (ConditionPassed(static_cast<Condition>(instr->Condition()))) {
-    // If the condition passes, set the status flags to the result of comparing
-    // the operands.
-    if (instr->Mask(ConditionalCompareMask) == CCMP) {
-      AddWithCarry(reg_size, true, op1, ~op2, 1);
-    } else {
-      ASSERT(instr->Mask(ConditionalCompareMask) == CCMN);
-      AddWithCarry(reg_size, true, op1, op2, 0);
-    }
-  } else {
-    // If the condition fails, set the status flags to the nzcv immediate.
-    nzcv().SetFlags(instr->Nzcv());
-  }
-}
-
-
-void Simulator::VisitLoadStoreUnsignedOffset(Instruction* instr) {
-  int offset = instr->ImmLSUnsigned() << instr->SizeLS();
-  LoadStoreHelper(instr, offset, Offset);
-}
-
-
-void Simulator::VisitLoadStoreUnscaledOffset(Instruction* instr) {
-  LoadStoreHelper(instr, instr->ImmLS(), Offset);
-}
-
-
-void Simulator::VisitLoadStorePreIndex(Instruction* instr) {
-  LoadStoreHelper(instr, instr->ImmLS(), PreIndex);
-}
-
-
-void Simulator::VisitLoadStorePostIndex(Instruction* instr) {
-  LoadStoreHelper(instr, instr->ImmLS(), PostIndex);
-}
-
-
-void Simulator::VisitLoadStoreRegisterOffset(Instruction* instr) {
-  Extend ext = static_cast<Extend>(instr->ExtendMode());
-  ASSERT((ext == UXTW) || (ext == UXTX) || (ext == SXTW) || (ext == SXTX));
-  unsigned shift_amount = instr->ImmShiftLS() * instr->SizeLS();
-
-  int64_t offset = ExtendValue(kXRegSizeInBits, xreg(instr->Rm()), ext,
-                               shift_amount);
-  LoadStoreHelper(instr, offset, Offset);
-}
-
-
-void Simulator::LoadStoreHelper(Instruction* instr,
-                                int64_t offset,
-                                AddrMode addrmode) {
-  unsigned srcdst = instr->Rt();
-  unsigned addr_reg = instr->Rn();
-  uint8_t* address = LoadStoreAddress(addr_reg, offset, addrmode);
-  int num_bytes = 1 << instr->SizeLS();
-  uint8_t* stack = NULL;
-
-  // Handle the writeback for stores before the store. On a CPU the writeback
-  // and the store are atomic, but when running on the simulator it is possible
-  // to be interrupted in between. The simulator is not thread safe and V8 does
-  // not require it to be to run JavaScript therefore the profiler may sample
-  // the "simulated" CPU in the middle of load/store with writeback. The code
-  // below ensures that push operations are safe even when interrupted: the
-  // stack pointer will be decremented before adding an element to the stack.
-  if (instr->IsStore()) {
-    LoadStoreWriteBack(addr_reg, offset, addrmode);
-
-    // For store the address post writeback is used to check access below the
-    // stack.
-    stack = reinterpret_cast<uint8_t*>(sp());
-  }
-
-  LoadStoreOp op = static_cast<LoadStoreOp>(instr->Mask(LoadStoreOpMask));
-  switch (op) {
-    case LDRB_w:
-    case LDRH_w:
-    case LDR_w:
-    case LDR_x: set_xreg(srcdst, MemoryRead(address, num_bytes)); break;
-    case STRB_w:
-    case STRH_w:
-    case STR_w:
-    case STR_x: MemoryWrite(address, xreg(srcdst), num_bytes); break;
-    case LDRSB_w: {
-      set_wreg(srcdst,
-               ExtendValue(kWRegSizeInBits, MemoryRead8(address), SXTB));
-      break;
-    }
-    case LDRSB_x: {
-      set_xreg(srcdst,
-               ExtendValue(kXRegSizeInBits, MemoryRead8(address), SXTB));
-      break;
-    }
-    case LDRSH_w: {
-      set_wreg(srcdst,
-               ExtendValue(kWRegSizeInBits, MemoryRead16(address), SXTH));
-      break;
-    }
-    case LDRSH_x: {
-      set_xreg(srcdst,
-               ExtendValue(kXRegSizeInBits, MemoryRead16(address), SXTH));
-      break;
-    }
-    case LDRSW_x: {
-      set_xreg(srcdst,
-               ExtendValue(kXRegSizeInBits, MemoryRead32(address), SXTW));
-      break;
-    }
-    case LDR_s: set_sreg(srcdst, MemoryReadFP32(address)); break;
-    case LDR_d: set_dreg(srcdst, MemoryReadFP64(address)); break;
-    case STR_s: MemoryWriteFP32(address, sreg(srcdst)); break;
-    case STR_d: MemoryWriteFP64(address, dreg(srcdst)); break;
-    default: UNIMPLEMENTED();
-  }
-
-  // Handle the writeback for loads after the load to ensure safe pop
-  // operation even when interrupted in the middle of it. The stack pointer
-  // is only updated after the load so pop(fp) will never break the invariant
-  // sp <= fp expected while walking the stack in the sampler.
-  if (instr->IsLoad()) {
-    // For loads the address pre writeback is used to check access below the
-    // stack.
-    stack = reinterpret_cast<uint8_t*>(sp());
-
-    LoadStoreWriteBack(addr_reg, offset, addrmode);
-  }
-
-  // Accesses below the stack pointer (but above the platform stack limit) are
-  // not allowed in the ABI.
-  CheckMemoryAccess(address, stack);
-}
-
-
-void Simulator::VisitLoadStorePairOffset(Instruction* instr) {
-  LoadStorePairHelper(instr, Offset);
-}
-
-
-void Simulator::VisitLoadStorePairPreIndex(Instruction* instr) {
-  LoadStorePairHelper(instr, PreIndex);
-}
-
-
-void Simulator::VisitLoadStorePairPostIndex(Instruction* instr) {
-  LoadStorePairHelper(instr, PostIndex);
-}
-
-
-void Simulator::VisitLoadStorePairNonTemporal(Instruction* instr) {
-  LoadStorePairHelper(instr, Offset);
-}
-
-
-void Simulator::LoadStorePairHelper(Instruction* instr,
-                                    AddrMode addrmode) {
-  unsigned rt = instr->Rt();
-  unsigned rt2 = instr->Rt2();
-  unsigned addr_reg = instr->Rn();
-  int offset = instr->ImmLSPair() << instr->SizeLSPair();
-  uint8_t* address = LoadStoreAddress(addr_reg, offset, addrmode);
-  uint8_t* stack = NULL;
-
-  // Handle the writeback for stores before the store. On a CPU the writeback
-  // and the store are atomic, but when running on the simulator it is possible
-  // to be interrupted in between. The simulator is not thread safe and V8 does
-  // not require it to be to run JavaScript therefore the profiler may sample
-  // the "simulated" CPU in the middle of load/store with writeback. The code
-  // below ensures that push operations are safe even when interrupted: the
-  // stack pointer will be decremented before adding an element to the stack.
-  if (instr->IsStore()) {
-    LoadStoreWriteBack(addr_reg, offset, addrmode);
-
-    // For store the address post writeback is used to check access below the
-    // stack.
-    stack = reinterpret_cast<uint8_t*>(sp());
-  }
-
-  LoadStorePairOp op =
-    static_cast<LoadStorePairOp>(instr->Mask(LoadStorePairMask));
-
-  // 'rt' and 'rt2' can only be aliased for stores.
-  ASSERT(((op & LoadStorePairLBit) == 0) || (rt != rt2));
-
-  switch (op) {
-    case LDP_w: {
-      set_wreg(rt, MemoryRead32(address));
-      set_wreg(rt2, MemoryRead32(address + kWRegSize));
-      break;
-    }
-    case LDP_s: {
-      set_sreg(rt, MemoryReadFP32(address));
-      set_sreg(rt2, MemoryReadFP32(address + kSRegSize));
-      break;
-    }
-    case LDP_x: {
-      set_xreg(rt, MemoryRead64(address));
-      set_xreg(rt2, MemoryRead64(address + kXRegSize));
-      break;
-    }
-    case LDP_d: {
-      set_dreg(rt, MemoryReadFP64(address));
-      set_dreg(rt2, MemoryReadFP64(address + kDRegSize));
-      break;
-    }
-    case LDPSW_x: {
-      set_xreg(rt, ExtendValue(kXRegSizeInBits, MemoryRead32(address), SXTW));
-      set_xreg(rt2, ExtendValue(kXRegSizeInBits,
-               MemoryRead32(address + kWRegSize), SXTW));
-      break;
-    }
-    case STP_w: {
-      MemoryWrite32(address, wreg(rt));
-      MemoryWrite32(address + kWRegSize, wreg(rt2));
-      break;
-    }
-    case STP_s: {
-      MemoryWriteFP32(address, sreg(rt));
-      MemoryWriteFP32(address + kSRegSize, sreg(rt2));
-      break;
-    }
-    case STP_x: {
-      MemoryWrite64(address, xreg(rt));
-      MemoryWrite64(address + kXRegSize, xreg(rt2));
-      break;
-    }
-    case STP_d: {
-      MemoryWriteFP64(address, dreg(rt));
-      MemoryWriteFP64(address + kDRegSize, dreg(rt2));
-      break;
-    }
-    default: UNREACHABLE();
-  }
-
-  // Handle the writeback for loads after the load to ensure safe pop
-  // operation even when interrupted in the middle of it. The stack pointer
-  // is only updated after the load so pop(fp) will never break the invariant
-  // sp <= fp expected while walking the stack in the sampler.
-  if (instr->IsLoad()) {
-    // For loads the address pre writeback is used to check access below the
-    // stack.
-    stack = reinterpret_cast<uint8_t*>(sp());
-
-    LoadStoreWriteBack(addr_reg, offset, addrmode);
-  }
-
-  // Accesses below the stack pointer (but above the platform stack limit) are
-  // not allowed in the ABI.
-  CheckMemoryAccess(address, stack);
-}
-
-
-void Simulator::VisitLoadLiteral(Instruction* instr) {
-  uint8_t* address = instr->LiteralAddress();
-  unsigned rt = instr->Rt();
-
-  switch (instr->Mask(LoadLiteralMask)) {
-    case LDR_w_lit: set_wreg(rt, MemoryRead32(address));  break;
-    case LDR_x_lit: set_xreg(rt, MemoryRead64(address));  break;
-    case LDR_s_lit: set_sreg(rt, MemoryReadFP32(address));  break;
-    case LDR_d_lit: set_dreg(rt, MemoryReadFP64(address));  break;
-    default: UNREACHABLE();
-  }
-}
-
-
-uint8_t* Simulator::LoadStoreAddress(unsigned addr_reg,
-                                     int64_t offset,
-                                     AddrMode addrmode) {
-  const unsigned kSPRegCode = kSPRegInternalCode & kRegCodeMask;
-  int64_t address = xreg(addr_reg, Reg31IsStackPointer);
-  if ((addr_reg == kSPRegCode) && ((address % 16) != 0)) {
-    // When the base register is SP the stack pointer is required to be
-    // quadword aligned prior to the address calculation and write-backs.
-    // Misalignment will cause a stack alignment fault.
-    FATAL("ALIGNMENT EXCEPTION");
-  }
-
-  if ((addrmode == Offset) || (addrmode == PreIndex)) {
-    address += offset;
-  }
-
-  return reinterpret_cast<uint8_t*>(address);
-}
-
-
-void Simulator::LoadStoreWriteBack(unsigned addr_reg,
-                                   int64_t offset,
-                                   AddrMode addrmode) {
-  if ((addrmode == PreIndex) || (addrmode == PostIndex)) {
-    ASSERT(offset != 0);
-    uint64_t address = xreg(addr_reg, Reg31IsStackPointer);
-    set_reg(addr_reg, address + offset, Reg31IsStackPointer);
-  }
-}
-
-
-void Simulator::CheckMemoryAccess(uint8_t* address, uint8_t* stack) {
-  if ((address >= stack_limit_) && (address < stack)) {
-    fprintf(stream_, "ACCESS BELOW STACK POINTER:\n");
-    fprintf(stream_, "  sp is here:          0x%16p\n", stack);
-    fprintf(stream_, "  access was here:     0x%16p\n", address);
-    fprintf(stream_, "  stack limit is here: 0x%16p\n", stack_limit_);
-    fprintf(stream_, "\n");
-    FATAL("ACCESS BELOW STACK POINTER");
-  }
-}
-
-
-uint64_t Simulator::MemoryRead(uint8_t* address, unsigned num_bytes) {
-  ASSERT(address != NULL);
-  ASSERT((num_bytes > 0) && (num_bytes <= sizeof(uint64_t)));
-  uint64_t read = 0;
-  memcpy(&read, address, num_bytes);
-  return read;
-}
-
-
-uint8_t Simulator::MemoryRead8(uint8_t* address) {
-  return MemoryRead(address, sizeof(uint8_t));
-}
-
-
-uint16_t Simulator::MemoryRead16(uint8_t* address) {
-  return MemoryRead(address, sizeof(uint16_t));
-}
-
-
-uint32_t Simulator::MemoryRead32(uint8_t* address) {
-  return MemoryRead(address, sizeof(uint32_t));
-}
-
-
-float Simulator::MemoryReadFP32(uint8_t* address) {
-  return rawbits_to_float(MemoryRead32(address));
-}
-
-
-uint64_t Simulator::MemoryRead64(uint8_t* address) {
-  return MemoryRead(address, sizeof(uint64_t));
-}
-
-
-double Simulator::MemoryReadFP64(uint8_t* address) {
-  return rawbits_to_double(MemoryRead64(address));
-}
-
-
-void Simulator::MemoryWrite(uint8_t* address,
-                            uint64_t value,
-                            unsigned num_bytes) {
-  ASSERT(address != NULL);
-  ASSERT((num_bytes > 0) && (num_bytes <= sizeof(uint64_t)));
-
-  LogWrite(address, value, num_bytes);
-  memcpy(address, &value, num_bytes);
-}
-
-
-void Simulator::MemoryWrite32(uint8_t* address, uint32_t value) {
-  MemoryWrite(address, value, sizeof(uint32_t));
-}
-
-
-void Simulator::MemoryWriteFP32(uint8_t* address, float value) {
-  MemoryWrite32(address, float_to_rawbits(value));
-}
-
-
-void Simulator::MemoryWrite64(uint8_t* address, uint64_t value) {
-  MemoryWrite(address, value, sizeof(uint64_t));
-}
-
-
-void Simulator::MemoryWriteFP64(uint8_t* address, double value) {
-  MemoryWrite64(address, double_to_rawbits(value));
-}
-
-
-void Simulator::VisitMoveWideImmediate(Instruction* instr) {
-  MoveWideImmediateOp mov_op =
-    static_cast<MoveWideImmediateOp>(instr->Mask(MoveWideImmediateMask));
-  int64_t new_xn_val = 0;
-
-  bool is_64_bits = instr->SixtyFourBits() == 1;
-  // Shift is limited for W operations.
-  ASSERT(is_64_bits || (instr->ShiftMoveWide() < 2));
-
-  // Get the shifted immediate.
-  int64_t shift = instr->ShiftMoveWide() * 16;
-  int64_t shifted_imm16 = instr->ImmMoveWide() << shift;
-
-  // Compute the new value.
-  switch (mov_op) {
-    case MOVN_w:
-    case MOVN_x: {
-        new_xn_val = ~shifted_imm16;
-        if (!is_64_bits) new_xn_val &= kWRegMask;
-      break;
-    }
-    case MOVK_w:
-    case MOVK_x: {
-        unsigned reg_code = instr->Rd();
-        int64_t prev_xn_val = is_64_bits ? xreg(reg_code)
-                                         : wreg(reg_code);
-        new_xn_val = (prev_xn_val & ~(0xffffL << shift)) | shifted_imm16;
-      break;
-    }
-    case MOVZ_w:
-    case MOVZ_x: {
-        new_xn_val = shifted_imm16;
-      break;
-    }
-    default:
-      UNREACHABLE();
-  }
-
-  // Update the destination register.
-  set_xreg(instr->Rd(), new_xn_val);
-}
-
-
-void Simulator::VisitConditionalSelect(Instruction* instr) {
-  uint64_t new_val = xreg(instr->Rn());
-
-  if (ConditionFailed(static_cast<Condition>(instr->Condition()))) {
-    new_val = xreg(instr->Rm());
-    switch (instr->Mask(ConditionalSelectMask)) {
-      case CSEL_w:
-      case CSEL_x: break;
-      case CSINC_w:
-      case CSINC_x: new_val++; break;
-      case CSINV_w:
-      case CSINV_x: new_val = ~new_val; break;
-      case CSNEG_w:
-      case CSNEG_x: new_val = -new_val; break;
-      default: UNIMPLEMENTED();
-    }
-  }
-  unsigned reg_size = instr->SixtyFourBits() ? kXRegSizeInBits
-                                             : kWRegSizeInBits;
-  set_reg(reg_size, instr->Rd(), new_val);
-}
-
-
-void Simulator::VisitDataProcessing1Source(Instruction* instr) {
-  unsigned dst = instr->Rd();
-  unsigned src = instr->Rn();
-
-  switch (instr->Mask(DataProcessing1SourceMask)) {
-    case RBIT_w: set_wreg(dst, ReverseBits(wreg(src), kWRegSizeInBits)); break;
-    case RBIT_x: set_xreg(dst, ReverseBits(xreg(src), kXRegSizeInBits)); break;
-    case REV16_w: set_wreg(dst, ReverseBytes(wreg(src), Reverse16)); break;
-    case REV16_x: set_xreg(dst, ReverseBytes(xreg(src), Reverse16)); break;
-    case REV_w: set_wreg(dst, ReverseBytes(wreg(src), Reverse32)); break;
-    case REV32_x: set_xreg(dst, ReverseBytes(xreg(src), Reverse32)); break;
-    case REV_x: set_xreg(dst, ReverseBytes(xreg(src), Reverse64)); break;
-    case CLZ_w: set_wreg(dst, CountLeadingZeros(wreg(src), kWRegSizeInBits));
-                break;
-    case CLZ_x: set_xreg(dst, CountLeadingZeros(xreg(src), kXRegSizeInBits));
-                break;
-    case CLS_w: {
-      set_wreg(dst, CountLeadingSignBits(wreg(src), kWRegSizeInBits));
-      break;
-    }
-    case CLS_x: {
-      set_xreg(dst, CountLeadingSignBits(xreg(src), kXRegSizeInBits));
-      break;
-    }
-    default: UNIMPLEMENTED();
-  }
-}
-
-
-uint64_t Simulator::ReverseBits(uint64_t value, unsigned num_bits) {
-  ASSERT((num_bits == kWRegSizeInBits) || (num_bits == kXRegSizeInBits));
-  uint64_t result = 0;
-  for (unsigned i = 0; i < num_bits; i++) {
-    result = (result << 1) | (value & 1);
-    value >>= 1;
-  }
-  return result;
-}
-
-
-uint64_t Simulator::ReverseBytes(uint64_t value, ReverseByteMode mode) {
-  // Split the 64-bit value into an 8-bit array, where b[0] is the least
-  // significant byte, and b[7] is the most significant.
-  uint8_t bytes[8];
-  uint64_t mask = 0xff00000000000000UL;
-  for (int i = 7; i >= 0; i--) {
-    bytes[i] = (value & mask) >> (i * 8);
-    mask >>= 8;
-  }
-
-  // Permutation tables for REV instructions.
-  //  permute_table[Reverse16] is used by REV16_x, REV16_w
-  //  permute_table[Reverse32] is used by REV32_x, REV_w
-  //  permute_table[Reverse64] is used by REV_x
-  ASSERT((Reverse16 == 0) && (Reverse32 == 1) && (Reverse64 == 2));
-  static const uint8_t permute_table[3][8] = { {6, 7, 4, 5, 2, 3, 0, 1},
-                                               {4, 5, 6, 7, 0, 1, 2, 3},
-                                               {0, 1, 2, 3, 4, 5, 6, 7} };
-  uint64_t result = 0;
-  for (int i = 0; i < 8; i++) {
-    result <<= 8;
-    result |= bytes[permute_table[mode][i]];
-  }
-  return result;
-}
-
-
-void Simulator::VisitDataProcessing2Source(Instruction* instr) {
-  Shift shift_op = NO_SHIFT;
-  int64_t result = 0;
-  switch (instr->Mask(DataProcessing2SourceMask)) {
-    case SDIV_w: {
-      int32_t rn = wreg(instr->Rn());
-      int32_t rm = wreg(instr->Rm());
-      if ((rn == kWMinInt) && (rm == -1)) {
-        result = kWMinInt;
-      } else if (rm == 0) {
-        // Division by zero can be trapped, but not on A-class processors.
-        result = 0;
-      } else {
-        result = rn / rm;
-      }
-      break;
-    }
-    case SDIV_x: {
-      int64_t rn = xreg(instr->Rn());
-      int64_t rm = xreg(instr->Rm());
-      if ((rn == kXMinInt) && (rm == -1)) {
-        result = kXMinInt;
-      } else if (rm == 0) {
-        // Division by zero can be trapped, but not on A-class processors.
-        result = 0;
-      } else {
-        result = rn / rm;
-      }
-      break;
-    }
-    case UDIV_w: {
-      uint32_t rn = static_cast<uint32_t>(wreg(instr->Rn()));
-      uint32_t rm = static_cast<uint32_t>(wreg(instr->Rm()));
-      if (rm == 0) {
-        // Division by zero can be trapped, but not on A-class processors.
-        result = 0;
-      } else {
-        result = rn / rm;
-      }
-      break;
-    }
-    case UDIV_x: {
-      uint64_t rn = static_cast<uint64_t>(xreg(instr->Rn()));
-      uint64_t rm = static_cast<uint64_t>(xreg(instr->Rm()));
-      if (rm == 0) {
-        // Division by zero can be trapped, but not on A-class processors.
-        result = 0;
-      } else {
-        result = rn / rm;
-      }
-      break;
-    }
-    case LSLV_w:
-    case LSLV_x: shift_op = LSL; break;
-    case LSRV_w:
-    case LSRV_x: shift_op = LSR; break;
-    case ASRV_w:
-    case ASRV_x: shift_op = ASR; break;
-    case RORV_w:
-    case RORV_x: shift_op = ROR; break;
-    default: UNIMPLEMENTED();
-  }
-
-  unsigned reg_size = instr->SixtyFourBits() ? kXRegSizeInBits
-                                             : kWRegSizeInBits;
-  if (shift_op != NO_SHIFT) {
-    // Shift distance encoded in the least-significant five/six bits of the
-    // register.
-    int mask = (instr->SixtyFourBits() == 1) ? 0x3f : 0x1f;
-    unsigned shift = wreg(instr->Rm()) & mask;
-    result = ShiftOperand(reg_size, reg(reg_size, instr->Rn()), shift_op,
-                          shift);
-  }
-  set_reg(reg_size, instr->Rd(), result);
-}
-
-
-// The algorithm used is described in section 8.2 of
-//   Hacker's Delight, by Henry S. Warren, Jr.
-// It assumes that a right shift on a signed integer is an arithmetic shift.
-static int64_t MultiplyHighSigned(int64_t u, int64_t v) {
-  uint64_t u0, v0, w0;
-  int64_t u1, v1, w1, w2, t;
-
-  u0 = u & 0xffffffffL;
-  u1 = u >> 32;
-  v0 = v & 0xffffffffL;
-  v1 = v >> 32;
-
-  w0 = u0 * v0;
-  t = u1 * v0 + (w0 >> 32);
-  w1 = t & 0xffffffffL;
-  w2 = t >> 32;
-  w1 = u0 * v1 + w1;
-
-  return u1 * v1 + w2 + (w1 >> 32);
-}
-
-
-void Simulator::VisitDataProcessing3Source(Instruction* instr) {
-  unsigned reg_size = instr->SixtyFourBits() ? kXRegSizeInBits
-                                             : kWRegSizeInBits;
-
-  int64_t result = 0;
-  // Extract and sign- or zero-extend 32-bit arguments for widening operations.
-  uint64_t rn_u32 = reg<uint32_t>(instr->Rn());
-  uint64_t rm_u32 = reg<uint32_t>(instr->Rm());
-  int64_t rn_s32 = reg<int32_t>(instr->Rn());
-  int64_t rm_s32 = reg<int32_t>(instr->Rm());
-  switch (instr->Mask(DataProcessing3SourceMask)) {
-    case MADD_w:
-    case MADD_x:
-      result = xreg(instr->Ra()) + (xreg(instr->Rn()) * xreg(instr->Rm()));
-      break;
-    case MSUB_w:
-    case MSUB_x:
-      result = xreg(instr->Ra()) - (xreg(instr->Rn()) * xreg(instr->Rm()));
-      break;
-    case SMADDL_x: result = xreg(instr->Ra()) + (rn_s32 * rm_s32); break;
-    case SMSUBL_x: result = xreg(instr->Ra()) - (rn_s32 * rm_s32); break;
-    case UMADDL_x: result = xreg(instr->Ra()) + (rn_u32 * rm_u32); break;
-    case UMSUBL_x: result = xreg(instr->Ra()) - (rn_u32 * rm_u32); break;
-    case SMULH_x:
-      ASSERT(instr->Ra() == kZeroRegCode);
-      result = MultiplyHighSigned(xreg(instr->Rn()), xreg(instr->Rm()));
-      break;
-    default: UNIMPLEMENTED();
-  }
-  set_reg(reg_size, instr->Rd(), result);
-}
-
-
-void Simulator::VisitBitfield(Instruction* instr) {
-  unsigned reg_size = instr->SixtyFourBits() ? kXRegSizeInBits
-                                             : kWRegSizeInBits;
-  int64_t reg_mask = instr->SixtyFourBits() ? kXRegMask : kWRegMask;
-  int64_t R = instr->ImmR();
-  int64_t S = instr->ImmS();
-  int64_t diff = S - R;
-  int64_t mask;
-  if (diff >= 0) {
-    mask = diff < reg_size - 1 ? (1L << (diff + 1)) - 1
-                               : reg_mask;
-  } else {
-    mask = ((1L << (S + 1)) - 1);
-    mask = (static_cast<uint64_t>(mask) >> R) | (mask << (reg_size - R));
-    diff += reg_size;
-  }
-
-  // inzero indicates if the extracted bitfield is inserted into the
-  // destination register value or in zero.
-  // If extend is true, extend the sign of the extracted bitfield.
-  bool inzero = false;
-  bool extend = false;
-  switch (instr->Mask(BitfieldMask)) {
-    case BFM_x:
-    case BFM_w:
-      break;
-    case SBFM_x:
-    case SBFM_w:
-      inzero = true;
-      extend = true;
-      break;
-    case UBFM_x:
-    case UBFM_w:
-      inzero = true;
-      break;
-    default:
-      UNIMPLEMENTED();
-  }
-
-  int64_t dst = inzero ? 0 : reg(reg_size, instr->Rd());
-  int64_t src = reg(reg_size, instr->Rn());
-  // Rotate source bitfield into place.
-  int64_t result = (static_cast<uint64_t>(src) >> R) | (src << (reg_size - R));
-  // Determine the sign extension.
-  int64_t topbits = ((1L << (reg_size - diff - 1)) - 1) << (diff + 1);
-  int64_t signbits = extend && ((src >> S) & 1) ? topbits : 0;
-
-  // Merge sign extension, dest/zero and bitfield.
-  result = signbits | (result & mask) | (dst & ~mask);
-
-  set_reg(reg_size, instr->Rd(), result);
-}
-
-
-void Simulator::VisitExtract(Instruction* instr) {
-  unsigned lsb = instr->ImmS();
-  unsigned reg_size = (instr->SixtyFourBits() == 1) ? kXRegSizeInBits
-                                                    : kWRegSizeInBits;
-  set_reg(reg_size,
-          instr->Rd(),
-          (static_cast<uint64_t>(reg(reg_size, instr->Rm())) >> lsb) |
-          (reg(reg_size, instr->Rn()) << (reg_size - lsb)));
-}
-
-
-void Simulator::VisitFPImmediate(Instruction* instr) {
-  AssertSupportedFPCR();
-
-  unsigned dest = instr->Rd();
-  switch (instr->Mask(FPImmediateMask)) {
-    case FMOV_s_imm: set_sreg(dest, instr->ImmFP32()); break;
-    case FMOV_d_imm: set_dreg(dest, instr->ImmFP64()); break;
-    default: UNREACHABLE();
-  }
-}
-
-
-void Simulator::VisitFPIntegerConvert(Instruction* instr) {
-  AssertSupportedFPCR();
-
-  unsigned dst = instr->Rd();
-  unsigned src = instr->Rn();
-
-  FPRounding round = fpcr().RMode();
-
-  switch (instr->Mask(FPIntegerConvertMask)) {
-    case FCVTAS_ws: set_wreg(dst, FPToInt32(sreg(src), FPTieAway)); break;
-    case FCVTAS_xs: set_xreg(dst, FPToInt64(sreg(src), FPTieAway)); break;
-    case FCVTAS_wd: set_wreg(dst, FPToInt32(dreg(src), FPTieAway)); break;
-    case FCVTAS_xd: set_xreg(dst, FPToInt64(dreg(src), FPTieAway)); break;
-    case FCVTAU_ws: set_wreg(dst, FPToUInt32(sreg(src), FPTieAway)); break;
-    case FCVTAU_xs: set_xreg(dst, FPToUInt64(sreg(src), FPTieAway)); break;
-    case FCVTAU_wd: set_wreg(dst, FPToUInt32(dreg(src), FPTieAway)); break;
-    case FCVTAU_xd: set_xreg(dst, FPToUInt64(dreg(src), FPTieAway)); break;
-    case FCVTMS_ws:
-      set_wreg(dst, FPToInt32(sreg(src), FPNegativeInfinity));
-      break;
-    case FCVTMS_xs:
-      set_xreg(dst, FPToInt64(sreg(src), FPNegativeInfinity));
-      break;
-    case FCVTMS_wd:
-      set_wreg(dst, FPToInt32(dreg(src), FPNegativeInfinity));
-      break;
-    case FCVTMS_xd:
-      set_xreg(dst, FPToInt64(dreg(src), FPNegativeInfinity));
-      break;
-    case FCVTMU_ws:
-      set_wreg(dst, FPToUInt32(sreg(src), FPNegativeInfinity));
-      break;
-    case FCVTMU_xs:
-      set_xreg(dst, FPToUInt64(sreg(src), FPNegativeInfinity));
-      break;
-    case FCVTMU_wd:
-      set_wreg(dst, FPToUInt32(dreg(src), FPNegativeInfinity));
-      break;
-    case FCVTMU_xd:
-      set_xreg(dst, FPToUInt64(dreg(src), FPNegativeInfinity));
-      break;
-    case FCVTNS_ws: set_wreg(dst, FPToInt32(sreg(src), FPTieEven)); break;
-    case FCVTNS_xs: set_xreg(dst, FPToInt64(sreg(src), FPTieEven)); break;
-    case FCVTNS_wd: set_wreg(dst, FPToInt32(dreg(src), FPTieEven)); break;
-    case FCVTNS_xd: set_xreg(dst, FPToInt64(dreg(src), FPTieEven)); break;
-    case FCVTNU_ws: set_wreg(dst, FPToUInt32(sreg(src), FPTieEven)); break;
-    case FCVTNU_xs: set_xreg(dst, FPToUInt64(sreg(src), FPTieEven)); break;
-    case FCVTNU_wd: set_wreg(dst, FPToUInt32(dreg(src), FPTieEven)); break;
-    case FCVTNU_xd: set_xreg(dst, FPToUInt64(dreg(src), FPTieEven)); break;
-    case FCVTZS_ws: set_wreg(dst, FPToInt32(sreg(src), FPZero)); break;
-    case FCVTZS_xs: set_xreg(dst, FPToInt64(sreg(src), FPZero)); break;
-    case FCVTZS_wd: set_wreg(dst, FPToInt32(dreg(src), FPZero)); break;
-    case FCVTZS_xd: set_xreg(dst, FPToInt64(dreg(src), FPZero)); break;
-    case FCVTZU_ws: set_wreg(dst, FPToUInt32(sreg(src), FPZero)); break;
-    case FCVTZU_xs: set_xreg(dst, FPToUInt64(sreg(src), FPZero)); break;
-    case FCVTZU_wd: set_wreg(dst, FPToUInt32(dreg(src), FPZero)); break;
-    case FCVTZU_xd: set_xreg(dst, FPToUInt64(dreg(src), FPZero)); break;
-    case FMOV_ws: set_wreg(dst, sreg_bits(src)); break;
-    case FMOV_xd: set_xreg(dst, dreg_bits(src)); break;
-    case FMOV_sw: set_sreg_bits(dst, wreg(src)); break;
-    case FMOV_dx: set_dreg_bits(dst, xreg(src)); break;
-
-    // A 32-bit input can be handled in the same way as a 64-bit input, since
-    // the sign- or zero-extension will not affect the conversion.
-    case SCVTF_dx: set_dreg(dst, FixedToDouble(xreg(src), 0, round)); break;
-    case SCVTF_dw: set_dreg(dst, FixedToDouble(wreg(src), 0, round)); break;
-    case UCVTF_dx: set_dreg(dst, UFixedToDouble(xreg(src), 0, round)); break;
-    case UCVTF_dw: {
-      set_dreg(dst, UFixedToDouble(reg<uint32_t>(src), 0, round));
-      break;
-    }
-    case SCVTF_sx: set_sreg(dst, FixedToFloat(xreg(src), 0, round)); break;
-    case SCVTF_sw: set_sreg(dst, FixedToFloat(wreg(src), 0, round)); break;
-    case UCVTF_sx: set_sreg(dst, UFixedToFloat(xreg(src), 0, round)); break;
-    case UCVTF_sw: {
-      set_sreg(dst, UFixedToFloat(reg<uint32_t>(src), 0, round));
-      break;
-    }
-
-    default: UNREACHABLE();
-  }
-}
-
-
-void Simulator::VisitFPFixedPointConvert(Instruction* instr) {
-  AssertSupportedFPCR();
-
-  unsigned dst = instr->Rd();
-  unsigned src = instr->Rn();
-  int fbits = 64 - instr->FPScale();
-
-  FPRounding round = fpcr().RMode();
-
-  switch (instr->Mask(FPFixedPointConvertMask)) {
-    // A 32-bit input can be handled in the same way as a 64-bit input, since
-    // the sign- or zero-extension will not affect the conversion.
-    case SCVTF_dx_fixed:
-      set_dreg(dst, FixedToDouble(xreg(src), fbits, round));
-      break;
-    case SCVTF_dw_fixed:
-      set_dreg(dst, FixedToDouble(wreg(src), fbits, round));
-      break;
-    case UCVTF_dx_fixed:
-      set_dreg(dst, UFixedToDouble(xreg(src), fbits, round));
-      break;
-    case UCVTF_dw_fixed: {
-      set_dreg(dst,
-               UFixedToDouble(reg<uint32_t>(src), fbits, round));
-      break;
-    }
-    case SCVTF_sx_fixed:
-      set_sreg(dst, FixedToFloat(xreg(src), fbits, round));
-      break;
-    case SCVTF_sw_fixed:
-      set_sreg(dst, FixedToFloat(wreg(src), fbits, round));
-      break;
-    case UCVTF_sx_fixed:
-      set_sreg(dst, UFixedToFloat(xreg(src), fbits, round));
-      break;
-    case UCVTF_sw_fixed: {
-      set_sreg(dst,
-               UFixedToFloat(reg<uint32_t>(src), fbits, round));
-      break;
-    }
-    default: UNREACHABLE();
-  }
-}
-
-
-int32_t Simulator::FPToInt32(double value, FPRounding rmode) {
-  value = FPRoundInt(value, rmode);
-  if (value >= kWMaxInt) {
-    return kWMaxInt;
-  } else if (value < kWMinInt) {
-    return kWMinInt;
-  }
-  return std::isnan(value) ? 0 : static_cast<int32_t>(value);
-}
-
-
-int64_t Simulator::FPToInt64(double value, FPRounding rmode) {
-  value = FPRoundInt(value, rmode);
-  if (value >= kXMaxInt) {
-    return kXMaxInt;
-  } else if (value < kXMinInt) {
-    return kXMinInt;
-  }
-  return std::isnan(value) ? 0 : static_cast<int64_t>(value);
-}
-
-
-uint32_t Simulator::FPToUInt32(double value, FPRounding rmode) {
-  value = FPRoundInt(value, rmode);
-  if (value >= kWMaxUInt) {
-    return kWMaxUInt;
-  } else if (value < 0.0) {
-    return 0;
-  }
-  return std::isnan(value) ? 0 : static_cast<uint32_t>(value);
-}
-
-
-uint64_t Simulator::FPToUInt64(double value, FPRounding rmode) {
-  value = FPRoundInt(value, rmode);
-  if (value >= kXMaxUInt) {
-    return kXMaxUInt;
-  } else if (value < 0.0) {
-    return 0;
-  }
-  return std::isnan(value) ? 0 : static_cast<uint64_t>(value);
-}
-
-
-void Simulator::VisitFPCompare(Instruction* instr) {
-  AssertSupportedFPCR();
-
-  unsigned reg_size = (instr->Mask(FP64) == FP64) ? kDRegSizeInBits
-                                                  : kSRegSizeInBits;
-  double fn_val = fpreg(reg_size, instr->Rn());
-
-  switch (instr->Mask(FPCompareMask)) {
-    case FCMP_s:
-    case FCMP_d: FPCompare(fn_val, fpreg(reg_size, instr->Rm())); break;
-    case FCMP_s_zero:
-    case FCMP_d_zero: FPCompare(fn_val, 0.0); break;
-    default: UNIMPLEMENTED();
-  }
-}
-
-
-void Simulator::VisitFPConditionalCompare(Instruction* instr) {
-  AssertSupportedFPCR();
-
-  switch (instr->Mask(FPConditionalCompareMask)) {
-    case FCCMP_s:
-    case FCCMP_d: {
-      if (ConditionPassed(static_cast<Condition>(instr->Condition()))) {
-        // If the condition passes, set the status flags to the result of
-        // comparing the operands.
-        unsigned reg_size = (instr->Mask(FP64) == FP64) ? kDRegSizeInBits
-                                                        : kSRegSizeInBits;
-        FPCompare(fpreg(reg_size, instr->Rn()), fpreg(reg_size, instr->Rm()));
-      } else {
-        // If the condition fails, set the status flags to the nzcv immediate.
-        nzcv().SetFlags(instr->Nzcv());
-      }
-      break;
-    }
-    default: UNIMPLEMENTED();
-  }
-}
-
-
-void Simulator::VisitFPConditionalSelect(Instruction* instr) {
-  AssertSupportedFPCR();
-
-  Instr selected;
-  if (ConditionPassed(static_cast<Condition>(instr->Condition()))) {
-    selected = instr->Rn();
-  } else {
-    selected = instr->Rm();
-  }
-
-  switch (instr->Mask(FPConditionalSelectMask)) {
-    case FCSEL_s: set_sreg(instr->Rd(), sreg(selected)); break;
-    case FCSEL_d: set_dreg(instr->Rd(), dreg(selected)); break;
-    default: UNIMPLEMENTED();
-  }
-}
-
-
-void Simulator::VisitFPDataProcessing1Source(Instruction* instr) {
-  AssertSupportedFPCR();
-
-  unsigned fd = instr->Rd();
-  unsigned fn = instr->Rn();
-
-  switch (instr->Mask(FPDataProcessing1SourceMask)) {
-    case FMOV_s: set_sreg(fd, sreg(fn)); break;
-    case FMOV_d: set_dreg(fd, dreg(fn)); break;
-    case FABS_s: set_sreg(fd, std::fabs(sreg(fn))); break;
-    case FABS_d: set_dreg(fd, std::fabs(dreg(fn))); break;
-    case FNEG_s: set_sreg(fd, -sreg(fn)); break;
-    case FNEG_d: set_dreg(fd, -dreg(fn)); break;
-    case FSQRT_s: set_sreg(fd, FPSqrt(sreg(fn))); break;
-    case FSQRT_d: set_dreg(fd, FPSqrt(dreg(fn))); break;
-    case FRINTA_s: set_sreg(fd, FPRoundInt(sreg(fn), FPTieAway)); break;
-    case FRINTA_d: set_dreg(fd, FPRoundInt(dreg(fn), FPTieAway)); break;
-    case FRINTN_s: set_sreg(fd, FPRoundInt(sreg(fn), FPTieEven)); break;
-    case FRINTN_d: set_dreg(fd, FPRoundInt(dreg(fn), FPTieEven)); break;
-    case FRINTZ_s: set_sreg(fd, FPRoundInt(sreg(fn), FPZero)); break;
-    case FRINTZ_d: set_dreg(fd, FPRoundInt(dreg(fn), FPZero)); break;
-    case FCVT_ds: set_dreg(fd, FPToDouble(sreg(fn))); break;
-    case FCVT_sd: set_sreg(fd, FPToFloat(dreg(fn), FPTieEven)); break;
-    default: UNIMPLEMENTED();
-  }
-}
-
-
-// Assemble the specified IEEE-754 components into the target type and apply
-// appropriate rounding.
-//  sign:     0 = positive, 1 = negative
-//  exponent: Unbiased IEEE-754 exponent.
-//  mantissa: The mantissa of the input. The top bit (which is not encoded for
-//            normal IEEE-754 values) must not be omitted. This bit has the
-//            value 'pow(2, exponent)'.
-//
-// The input value is assumed to be a normalized value. That is, the input may
-// not be infinity or NaN. If the source value is subnormal, it must be
-// normalized before calling this function such that the highest set bit in the
-// mantissa has the value 'pow(2, exponent)'.
-//
-// Callers should use FPRoundToFloat or FPRoundToDouble directly, rather than
-// calling a templated FPRound.
-template <class T, int ebits, int mbits>
-static T FPRound(int64_t sign, int64_t exponent, uint64_t mantissa,
-                 FPRounding round_mode) {
-  ASSERT((sign == 0) || (sign == 1));
-
-  // Only the FPTieEven rounding mode is implemented.
-  ASSERT(round_mode == FPTieEven);
-  USE(round_mode);
-
-  // Rounding can promote subnormals to normals, and normals to infinities. For
-  // example, a double with exponent 127 (FLT_MAX_EXP) would appear to be
-  // encodable as a float, but rounding based on the low-order mantissa bits
-  // could make it overflow. With ties-to-even rounding, this value would become
-  // an infinity.
-
-  // ---- Rounding Method ----
-  //
-  // The exponent is irrelevant in the rounding operation, so we treat the
-  // lowest-order bit that will fit into the result ('onebit') as having
-  // the value '1'. Similarly, the highest-order bit that won't fit into
-  // the result ('halfbit') has the value '0.5'. The 'point' sits between
-  // 'onebit' and 'halfbit':
-  //
-  //            These bits fit into the result.
-  //               |---------------------|
-  //  mantissa = 0bxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
-  //                                     ||
-  //                                    / |
-  //                                   /  halfbit
-  //                               onebit
-  //
-  // For subnormal outputs, the range of representable bits is smaller and
-  // the position of onebit and halfbit depends on the exponent of the
-  // input, but the method is otherwise similar.
-  //
-  //   onebit(frac)
-  //     |
-  //     | halfbit(frac)          halfbit(adjusted)
-  //     | /                      /
-  //     | |                      |
-  //  0b00.0 (exact)      -> 0b00.0 (exact)                    -> 0b00
-  //  0b00.0...           -> 0b00.0...                         -> 0b00
-  //  0b00.1 (exact)      -> 0b00.0111..111                    -> 0b00
-  //  0b00.1...           -> 0b00.1...                         -> 0b01
-  //  0b01.0 (exact)      -> 0b01.0 (exact)                    -> 0b01
-  //  0b01.0...           -> 0b01.0...                         -> 0b01
-  //  0b01.1 (exact)      -> 0b01.1 (exact)                    -> 0b10
-  //  0b01.1...           -> 0b01.1...                         -> 0b10
-  //  0b10.0 (exact)      -> 0b10.0 (exact)                    -> 0b10
-  //  0b10.0...           -> 0b10.0...                         -> 0b10
-  //  0b10.1 (exact)      -> 0b10.0111..111                    -> 0b10
-  //  0b10.1...           -> 0b10.1...                         -> 0b11
-  //  0b11.0 (exact)      -> 0b11.0 (exact)                    -> 0b11
-  //  ...                   /             |                      /   |
-  //                       /              |                     /    |
-  //                                                           /     |
-  // adjusted = frac - (halfbit(mantissa) & ~onebit(frac));   /      |
-  //
-  //                   mantissa = (mantissa >> shift) + halfbit(adjusted);
-
-  static const int mantissa_offset = 0;
-  static const int exponent_offset = mantissa_offset + mbits;
-  static const int sign_offset = exponent_offset + ebits;
-  STATIC_ASSERT(sign_offset == (sizeof(T) * kByteSize - 1));
-
-  // Bail out early for zero inputs.
-  if (mantissa == 0) {
-    return sign << sign_offset;
-  }
-
-  // If all bits in the exponent are set, the value is infinite or NaN.
-  // This is true for all binary IEEE-754 formats.
-  static const int infinite_exponent = (1 << ebits) - 1;
-  static const int max_normal_exponent = infinite_exponent - 1;
-
-  // Apply the exponent bias to encode it for the result. Doing this early makes
-  // it easy to detect values that will be infinite or subnormal.
-  exponent += max_normal_exponent >> 1;
-
-  if (exponent > max_normal_exponent) {
-    // Overflow: The input is too large for the result type to represent. The
-    // FPTieEven rounding mode handles overflows using infinities.
-    exponent = infinite_exponent;
-    mantissa = 0;
-    return (sign << sign_offset) |
-           (exponent << exponent_offset) |
-           (mantissa << mantissa_offset);
-  }
-
-  // Calculate the shift required to move the top mantissa bit to the proper
-  // place in the destination type.
-  const int highest_significant_bit = 63 - CountLeadingZeros(mantissa, 64);
-  int shift = highest_significant_bit - mbits;
-
-  if (exponent <= 0) {
-    // The output will be subnormal (before rounding).
-
-    // For subnormal outputs, the shift must be adjusted by the exponent. The +1
-    // is necessary because the exponent of a subnormal value (encoded as 0) is
-    // the same as the exponent of the smallest normal value (encoded as 1).
-    shift += -exponent + 1;
-
-    // Handle inputs that would produce a zero output.
-    //
-    // Shifts higher than highest_significant_bit+1 will always produce a zero
-    // result. A shift of exactly highest_significant_bit+1 might produce a
-    // non-zero result after rounding.
-    if (shift > (highest_significant_bit + 1)) {
-      // The result will always be +/-0.0.
-      return sign << sign_offset;
-    }
-
-    // Properly encode the exponent for a subnormal output.
-    exponent = 0;
-  } else {
-    // Clear the topmost mantissa bit, since this is not encoded in IEEE-754
-    // normal values.
-    mantissa &= ~(1UL << highest_significant_bit);
-  }
-
-  if (shift > 0) {
-    // We have to shift the mantissa to the right. Some precision is lost, so we
-    // need to apply rounding.
-    uint64_t onebit_mantissa = (mantissa >> (shift)) & 1;
-    uint64_t halfbit_mantissa = (mantissa >> (shift-1)) & 1;
-    uint64_t adjusted = mantissa - (halfbit_mantissa & ~onebit_mantissa);
-    T halfbit_adjusted = (adjusted >> (shift-1)) & 1;
-
-    T result = (sign << sign_offset) |
-               (exponent << exponent_offset) |
-               ((mantissa >> shift) << mantissa_offset);
-
-    // A very large mantissa can overflow during rounding. If this happens, the
-    // exponent should be incremented and the mantissa set to 1.0 (encoded as
-    // 0). Applying halfbit_adjusted after assembling the float has the nice
-    // side-effect that this case is handled for free.
-    //
-    // This also handles cases where a very large finite value overflows to
-    // infinity, or where a very large subnormal value overflows to become
-    // normal.
-    return result + halfbit_adjusted;
-  } else {
-    // We have to shift the mantissa to the left (or not at all). The input
-    // mantissa is exactly representable in the output mantissa, so apply no
-    // rounding correction.
-    return (sign << sign_offset) |
-           (exponent << exponent_offset) |
-           ((mantissa << -shift) << mantissa_offset);
-  }
-}
-
-
-// See FPRound for a description of this function.
-static inline double FPRoundToDouble(int64_t sign, int64_t exponent,
-                                     uint64_t mantissa, FPRounding round_mode) {
-  int64_t bits =
-      FPRound<int64_t, kDoubleExponentBits, kDoubleMantissaBits>(sign,
-                                                                 exponent,
-                                                                 mantissa,
-                                                                 round_mode);
-  return rawbits_to_double(bits);
-}
-
-
-// See FPRound for a description of this function.
-static inline float FPRoundToFloat(int64_t sign, int64_t exponent,
-                                   uint64_t mantissa, FPRounding round_mode) {
-  int32_t bits =
-      FPRound<int32_t, kFloatExponentBits, kFloatMantissaBits>(sign,
-                                                               exponent,
-                                                               mantissa,
-                                                               round_mode);
-  return rawbits_to_float(bits);
-}
-
-
-double Simulator::FixedToDouble(int64_t src, int fbits, FPRounding round) {
-  if (src >= 0) {
-    return UFixedToDouble(src, fbits, round);
-  } else {
-    // This works for all negative values, including INT64_MIN.
-    return -UFixedToDouble(-src, fbits, round);
-  }
-}
-
-
-double Simulator::UFixedToDouble(uint64_t src, int fbits, FPRounding round) {
-  // An input of 0 is a special case because the result is effectively
-  // subnormal: The exponent is encoded as 0 and there is no implicit 1 bit.
-  if (src == 0) {
-    return 0.0;
-  }
-
-  // Calculate the exponent. The highest significant bit will have the value
-  // 2^exponent.
-  const int highest_significant_bit = 63 - CountLeadingZeros(src, 64);
-  const int64_t exponent = highest_significant_bit - fbits;
-
-  return FPRoundToDouble(0, exponent, src, round);
-}
-
-
-float Simulator::FixedToFloat(int64_t src, int fbits, FPRounding round) {
-  if (src >= 0) {
-    return UFixedToFloat(src, fbits, round);
-  } else {
-    // This works for all negative values, including INT64_MIN.
-    return -UFixedToFloat(-src, fbits, round);
-  }
-}
-
-
-float Simulator::UFixedToFloat(uint64_t src, int fbits, FPRounding round) {
-  // An input of 0 is a special case because the result is effectively
-  // subnormal: The exponent is encoded as 0 and there is no implicit 1 bit.
-  if (src == 0) {
-    return 0.0f;
-  }
-
-  // Calculate the exponent. The highest significant bit will have the value
-  // 2^exponent.
-  const int highest_significant_bit = 63 - CountLeadingZeros(src, 64);
-  const int32_t exponent = highest_significant_bit - fbits;
-
-  return FPRoundToFloat(0, exponent, src, round);
-}
-
-
-double Simulator::FPRoundInt(double value, FPRounding round_mode) {
-  if ((value == 0.0) || (value == kFP64PositiveInfinity) ||
-      (value == kFP64NegativeInfinity)) {
-    return value;
-  } else if (std::isnan(value)) {
-    return FPProcessNaN(value);
-  }
-
-  double int_result = floor(value);
-  double error = value - int_result;
-  switch (round_mode) {
-    case FPTieAway: {
-      // If the error is greater than 0.5, or is equal to 0.5 and the integer
-      // result is positive, round up.
-      if ((error > 0.5) || ((error == 0.5) && (int_result >= 0.0))) {
-        int_result++;
-      }
-      break;
-    }
-    case FPTieEven: {
-      // If the error is greater than 0.5, or is equal to 0.5 and the integer
-      // result is odd, round up.
-      if ((error > 0.5) ||
-          ((error == 0.5) && (fmod(int_result, 2) != 0))) {
-        int_result++;
-      }
-      break;
-    }
-    case FPZero: {
-      // If value > 0 then we take floor(value)
-      // otherwise, ceil(value)
-      if (value < 0) {
-         int_result = ceil(value);
-      }
-      break;
-    }
-    case FPNegativeInfinity: {
-      // We always use floor(value).
-      break;
-    }
-    default: UNIMPLEMENTED();
-  }
-  return int_result;
-}
-
-
-double Simulator::FPToDouble(float value) {
-  switch (std::fpclassify(value)) {
-    case FP_NAN: {
-      if (fpcr().DN()) return kFP64DefaultNaN;
-
-      // Convert NaNs as the processor would:
-      //  - The sign is propagated.
-      //  - The payload (mantissa) is transferred entirely, except that the top
-      //    bit is forced to '1', making the result a quiet NaN. The unused
-      //    (low-order) payload bits are set to 0.
-      uint32_t raw = float_to_rawbits(value);
-
-      uint64_t sign = raw >> 31;
-      uint64_t exponent = (1 << 11) - 1;
-      uint64_t payload = unsigned_bitextract_64(21, 0, raw);
-      payload <<= (52 - 23);  // The unused low-order bits should be 0.
-      payload |= (1L << 51);  // Force a quiet NaN.
-
-      return rawbits_to_double((sign << 63) | (exponent << 52) | payload);
-    }
-
-    case FP_ZERO:
-    case FP_NORMAL:
-    case FP_SUBNORMAL:
-    case FP_INFINITE: {
-      // All other inputs are preserved in a standard cast, because every value
-      // representable using an IEEE-754 float is also representable using an
-      // IEEE-754 double.
-      return static_cast<double>(value);
-    }
-  }
-
-  UNREACHABLE();
-  return static_cast<double>(value);
-}
-
-
-float Simulator::FPToFloat(double value, FPRounding round_mode) {
-  // Only the FPTieEven rounding mode is implemented.
-  ASSERT(round_mode == FPTieEven);
-  USE(round_mode);
-
-  switch (std::fpclassify(value)) {
-    case FP_NAN: {
-      if (fpcr().DN()) return kFP32DefaultNaN;
-
-      // Convert NaNs as the processor would:
-      //  - The sign is propagated.
-      //  - The payload (mantissa) is transferred as much as possible, except
-      //    that the top bit is forced to '1', making the result a quiet NaN.
-      uint64_t raw = double_to_rawbits(value);
-
-      uint32_t sign = raw >> 63;
-      uint32_t exponent = (1 << 8) - 1;
-      uint32_t payload = unsigned_bitextract_64(50, 52 - 23, raw);
-      payload |= (1 << 22);   // Force a quiet NaN.
-
-      return rawbits_to_float((sign << 31) | (exponent << 23) | payload);
-    }
-
-    case FP_ZERO:
-    case FP_INFINITE: {
-      // In a C++ cast, any value representable in the target type will be
-      // unchanged. This is always the case for +/-0.0 and infinities.
-      return static_cast<float>(value);
-    }
-
-    case FP_NORMAL:
-    case FP_SUBNORMAL: {
-      // Convert double-to-float as the processor would, assuming that FPCR.FZ
-      // (flush-to-zero) is not set.
-      uint64_t raw = double_to_rawbits(value);
-      // Extract the IEEE-754 double components.
-      uint32_t sign = raw >> 63;
-      // Extract the exponent and remove the IEEE-754 encoding bias.
-      int32_t exponent = unsigned_bitextract_64(62, 52, raw) - 1023;
-      // Extract the mantissa and add the implicit '1' bit.
-      uint64_t mantissa = unsigned_bitextract_64(51, 0, raw);
-      if (std::fpclassify(value) == FP_NORMAL) {
-        mantissa |= (1UL << 52);
-      }
-      return FPRoundToFloat(sign, exponent, mantissa, round_mode);
-    }
-  }
-
-  UNREACHABLE();
-  return value;
-}
-
-
-void Simulator::VisitFPDataProcessing2Source(Instruction* instr) {
-  AssertSupportedFPCR();
-
-  unsigned fd = instr->Rd();
-  unsigned fn = instr->Rn();
-  unsigned fm = instr->Rm();
-
-  // Fmaxnm and Fminnm have special NaN handling.
-  switch (instr->Mask(FPDataProcessing2SourceMask)) {
-    case FMAXNM_s: set_sreg(fd, FPMaxNM(sreg(fn), sreg(fm))); return;
-    case FMAXNM_d: set_dreg(fd, FPMaxNM(dreg(fn), dreg(fm))); return;
-    case FMINNM_s: set_sreg(fd, FPMinNM(sreg(fn), sreg(fm))); return;
-    case FMINNM_d: set_dreg(fd, FPMinNM(dreg(fn), dreg(fm))); return;
-    default:
-      break;    // Fall through.
-  }
-
-  if (FPProcessNaNs(instr)) return;
-
-  switch (instr->Mask(FPDataProcessing2SourceMask)) {
-    case FADD_s: set_sreg(fd, FPAdd(sreg(fn), sreg(fm))); break;
-    case FADD_d: set_dreg(fd, FPAdd(dreg(fn), dreg(fm))); break;
-    case FSUB_s: set_sreg(fd, FPSub(sreg(fn), sreg(fm))); break;
-    case FSUB_d: set_dreg(fd, FPSub(dreg(fn), dreg(fm))); break;
-    case FMUL_s: set_sreg(fd, FPMul(sreg(fn), sreg(fm))); break;
-    case FMUL_d: set_dreg(fd, FPMul(dreg(fn), dreg(fm))); break;
-    case FDIV_s: set_sreg(fd, FPDiv(sreg(fn), sreg(fm))); break;
-    case FDIV_d: set_dreg(fd, FPDiv(dreg(fn), dreg(fm))); break;
-    case FMAX_s: set_sreg(fd, FPMax(sreg(fn), sreg(fm))); break;
-    case FMAX_d: set_dreg(fd, FPMax(dreg(fn), dreg(fm))); break;
-    case FMIN_s: set_sreg(fd, FPMin(sreg(fn), sreg(fm))); break;
-    case FMIN_d: set_dreg(fd, FPMin(dreg(fn), dreg(fm))); break;
-    case FMAXNM_s:
-    case FMAXNM_d:
-    case FMINNM_s:
-    case FMINNM_d:
-      // These were handled before the standard FPProcessNaNs() stage.
-      UNREACHABLE();
-    default: UNIMPLEMENTED();
-  }
-}
-
-
-void Simulator::VisitFPDataProcessing3Source(Instruction* instr) {
-  AssertSupportedFPCR();
-
-  unsigned fd = instr->Rd();
-  unsigned fn = instr->Rn();
-  unsigned fm = instr->Rm();
-  unsigned fa = instr->Ra();
-
-  // The C99 (and C++11) fma function performs a fused multiply-accumulate.
-  switch (instr->Mask(FPDataProcessing3SourceMask)) {
-    // fd = fa +/- (fn * fm)
-    case FMADD_s: set_sreg(fd, FPMulAdd(sreg(fa), sreg(fn), sreg(fm))); break;
-    case FMSUB_s: set_sreg(fd, FPMulAdd(sreg(fa), -sreg(fn), sreg(fm))); break;
-    case FMADD_d: set_dreg(fd, FPMulAdd(dreg(fa), dreg(fn), dreg(fm))); break;
-    case FMSUB_d: set_dreg(fd, FPMulAdd(dreg(fa), -dreg(fn), dreg(fm))); break;
-    // Negated variants of the above.
-    case FNMADD_s:
-      set_sreg(fd, FPMulAdd(-sreg(fa), -sreg(fn), sreg(fm)));
-      break;
-    case FNMSUB_s:
-      set_sreg(fd, FPMulAdd(-sreg(fa), sreg(fn), sreg(fm)));
-      break;
-    case FNMADD_d:
-      set_dreg(fd, FPMulAdd(-dreg(fa), -dreg(fn), dreg(fm)));
-      break;
-    case FNMSUB_d:
-      set_dreg(fd, FPMulAdd(-dreg(fa), dreg(fn), dreg(fm)));
-      break;
-    default: UNIMPLEMENTED();
-  }
-}
-
-
-template <typename T>
-T Simulator::FPAdd(T op1, T op2) {
-  // NaNs should be handled elsewhere.
-  ASSERT(!std::isnan(op1) && !std::isnan(op2));
-
-  if (isinf(op1) && isinf(op2) && (op1 != op2)) {
-    // inf + -inf returns the default NaN.
-    return FPDefaultNaN<T>();
-  } else {
-    // Other cases should be handled by standard arithmetic.
-    return op1 + op2;
-  }
-}
-
-
-template <typename T>
-T Simulator::FPDiv(T op1, T op2) {
-  // NaNs should be handled elsewhere.
-  ASSERT(!std::isnan(op1) && !std::isnan(op2));
-
-  if ((isinf(op1) && isinf(op2)) || ((op1 == 0.0) && (op2 == 0.0))) {
-    // inf / inf and 0.0 / 0.0 return the default NaN.
-    return FPDefaultNaN<T>();
-  } else {
-    // Other cases should be handled by standard arithmetic.
-    return op1 / op2;
-  }
-}
-
-
-template <typename T>
-T Simulator::FPMax(T a, T b) {
-  // NaNs should be handled elsewhere.
-  ASSERT(!std::isnan(a) && !std::isnan(b));
-
-  if ((a == 0.0) && (b == 0.0) &&
-      (copysign(1.0, a) != copysign(1.0, b))) {
-    // a and b are zero, and the sign differs: return +0.0.
-    return 0.0;
-  } else {
-    return (a > b) ? a : b;
-  }
-}
-
-
-template <typename T>
-T Simulator::FPMaxNM(T a, T b) {
-  if (IsQuietNaN(a) && !IsQuietNaN(b)) {
-    a = kFP64NegativeInfinity;
-  } else if (!IsQuietNaN(a) && IsQuietNaN(b)) {
-    b = kFP64NegativeInfinity;
-  }
-
-  T result = FPProcessNaNs(a, b);
-  return std::isnan(result) ? result : FPMax(a, b);
-}
-
-template <typename T>
-T Simulator::FPMin(T a, T b) {
-  // NaNs should be handled elsewhere.
-  ASSERT(!isnan(a) && !isnan(b));
-
-  if ((a == 0.0) && (b == 0.0) &&
-      (copysign(1.0, a) != copysign(1.0, b))) {
-    // a and b are zero, and the sign differs: return -0.0.
-    return -0.0;
-  } else {
-    return (a < b) ? a : b;
-  }
-}
-
-
-template <typename T>
-T Simulator::FPMinNM(T a, T b) {
-  if (IsQuietNaN(a) && !IsQuietNaN(b)) {
-    a = kFP64PositiveInfinity;
-  } else if (!IsQuietNaN(a) && IsQuietNaN(b)) {
-    b = kFP64PositiveInfinity;
-  }
-
-  T result = FPProcessNaNs(a, b);
-  return isnan(result) ? result : FPMin(a, b);
-}
-
-
-template <typename T>
-T Simulator::FPMul(T op1, T op2) {
-  // NaNs should be handled elsewhere.
-  ASSERT(!std::isnan(op1) && !std::isnan(op2));
-
-  if ((isinf(op1) && (op2 == 0.0)) || (isinf(op2) && (op1 == 0.0))) {
-    // inf * 0.0 returns the default NaN.
-    return FPDefaultNaN<T>();
-  } else {
-    // Other cases should be handled by standard arithmetic.
-    return op1 * op2;
-  }
-}
-
-
-template<typename T>
-T Simulator::FPMulAdd(T a, T op1, T op2) {
-  T result = FPProcessNaNs3(a, op1, op2);
-
-  T sign_a = copysign(1.0, a);
-  T sign_prod = copysign(1.0, op1) * copysign(1.0, op2);
-  bool isinf_prod = std::isinf(op1) || std::isinf(op2);
-  bool operation_generates_nan =
-      (std::isinf(op1) && (op2 == 0.0)) ||                      // inf * 0.0
-      (std::isinf(op2) && (op1 == 0.0)) ||                      // 0.0 * inf
-      (std::isinf(a) && isinf_prod && (sign_a != sign_prod));   // inf - inf
-
-  if (std::isnan(result)) {
-    // Generated NaNs override quiet NaNs propagated from a.
-    if (operation_generates_nan && IsQuietNaN(a)) {
-      return FPDefaultNaN<T>();
-    } else {
-      return result;
-    }
-  }
-
-  // If the operation would produce a NaN, return the default NaN.
-  if (operation_generates_nan) {
-    return FPDefaultNaN<T>();
-  }
-
-  // Work around broken fma implementations for exact zero results: The sign of
-  // exact 0.0 results is positive unless both a and op1 * op2 are negative.
-  if (((op1 == 0.0) || (op2 == 0.0)) && (a == 0.0)) {
-    return ((sign_a < 0) && (sign_prod < 0)) ? -0.0 : 0.0;
-  }
-
-  result = FusedMultiplyAdd(op1, op2, a);
-  ASSERT(!std::isnan(result));
-
-  // Work around broken fma implementations for rounded zero results: If a is
-  // 0.0, the sign of the result is the sign of op1 * op2 before rounding.
-  if ((a == 0.0) && (result == 0.0)) {
-    return copysign(0.0, sign_prod);
-  }
-
-  return result;
-}
-
-
-template <typename T>
-T Simulator::FPSqrt(T op) {
-  if (std::isnan(op)) {
-    return FPProcessNaN(op);
-  } else if (op < 0.0) {
-    return FPDefaultNaN<T>();
-  } else {
-    return std::sqrt(op);
-  }
-}
-
-
-template <typename T>
-T Simulator::FPSub(T op1, T op2) {
-  // NaNs should be handled elsewhere.
-  ASSERT(!std::isnan(op1) && !std::isnan(op2));
-
-  if (isinf(op1) && isinf(op2) && (op1 == op2)) {
-    // inf - inf returns the default NaN.
-    return FPDefaultNaN<T>();
-  } else {
-    // Other cases should be handled by standard arithmetic.
-    return op1 - op2;
-  }
-}
-
-
-template <typename T>
-T Simulator::FPProcessNaN(T op) {
-  ASSERT(std::isnan(op));
-  return fpcr().DN() ? FPDefaultNaN<T>() : ToQuietNaN(op);
-}
-
-
-template <typename T>
-T Simulator::FPProcessNaNs(T op1, T op2) {
-  if (IsSignallingNaN(op1)) {
-    return FPProcessNaN(op1);
-  } else if (IsSignallingNaN(op2)) {
-    return FPProcessNaN(op2);
-  } else if (std::isnan(op1)) {
-    ASSERT(IsQuietNaN(op1));
-    return FPProcessNaN(op1);
-  } else if (std::isnan(op2)) {
-    ASSERT(IsQuietNaN(op2));
-    return FPProcessNaN(op2);
-  } else {
-    return 0.0;
-  }
-}
-
-
-template <typename T>
-T Simulator::FPProcessNaNs3(T op1, T op2, T op3) {
-  if (IsSignallingNaN(op1)) {
-    return FPProcessNaN(op1);
-  } else if (IsSignallingNaN(op2)) {
-    return FPProcessNaN(op2);
-  } else if (IsSignallingNaN(op3)) {
-    return FPProcessNaN(op3);
-  } else if (std::isnan(op1)) {
-    ASSERT(IsQuietNaN(op1));
-    return FPProcessNaN(op1);
-  } else if (std::isnan(op2)) {
-    ASSERT(IsQuietNaN(op2));
-    return FPProcessNaN(op2);
-  } else if (std::isnan(op3)) {
-    ASSERT(IsQuietNaN(op3));
-    return FPProcessNaN(op3);
-  } else {
-    return 0.0;
-  }
-}
-
-
-bool Simulator::FPProcessNaNs(Instruction* instr) {
-  unsigned fd = instr->Rd();
-  unsigned fn = instr->Rn();
-  unsigned fm = instr->Rm();
-  bool done = false;
-
-  if (instr->Mask(FP64) == FP64) {
-    double result = FPProcessNaNs(dreg(fn), dreg(fm));
-    if (std::isnan(result)) {
-      set_dreg(fd, result);
-      done = true;
-    }
-  } else {
-    float result = FPProcessNaNs(sreg(fn), sreg(fm));
-    if (std::isnan(result)) {
-      set_sreg(fd, result);
-      done = true;
-    }
-  }
-
-  return done;
-}
-
-
-void Simulator::VisitSystem(Instruction* instr) {
-  // Some system instructions hijack their Op and Cp fields to represent a
-  // range of immediates instead of indicating a different instruction. This
-  // makes the decoding tricky.
-  if (instr->Mask(SystemSysRegFMask) == SystemSysRegFixed) {
-    switch (instr->Mask(SystemSysRegMask)) {
-      case MRS: {
-        switch (instr->ImmSystemRegister()) {
-          case NZCV: set_xreg(instr->Rt(), nzcv().RawValue()); break;
-          case FPCR: set_xreg(instr->Rt(), fpcr().RawValue()); break;
-          default: UNIMPLEMENTED();
-        }
-        break;
-      }
-      case MSR: {
-        switch (instr->ImmSystemRegister()) {
-          case NZCV: nzcv().SetRawValue(xreg(instr->Rt())); break;
-          case FPCR: fpcr().SetRawValue(xreg(instr->Rt())); break;
-          default: UNIMPLEMENTED();
-        }
-        break;
-      }
-    }
-  } else if (instr->Mask(SystemHintFMask) == SystemHintFixed) {
-    ASSERT(instr->Mask(SystemHintMask) == HINT);
-    switch (instr->ImmHint()) {
-      case NOP: break;
-      default: UNIMPLEMENTED();
-    }
-  } else if (instr->Mask(MemBarrierFMask) == MemBarrierFixed) {
-    __sync_synchronize();
-  } else {
-    UNIMPLEMENTED();
-  }
-}
-
-
-bool Simulator::GetValue(const char* desc, int64_t* value) {
-  int regnum = CodeFromName(desc);
-  if (regnum >= 0) {
-    unsigned code = regnum;
-    if (code == kZeroRegCode) {
-      // Catch the zero register and return 0.
-      *value = 0;
-      return true;
-    } else if (code == kSPRegInternalCode) {
-      // Translate the stack pointer code to 31, for Reg31IsStackPointer.
-      code = 31;
-    }
-    if (desc[0] == 'w') {
-      *value = wreg(code, Reg31IsStackPointer);
-    } else {
-      *value = xreg(code, Reg31IsStackPointer);
-    }
-    return true;
-  } else if (strncmp(desc, "0x", 2) == 0) {
-    return SScanF(desc + 2, "%" SCNx64,
-                  reinterpret_cast<uint64_t*>(value)) == 1;
-  } else {
-    return SScanF(desc, "%" SCNu64,
-                  reinterpret_cast<uint64_t*>(value)) == 1;
-  }
-}
-
-
-bool Simulator::PrintValue(const char* desc) {
-  if (strcmp(desc, "csp") == 0) {
-    ASSERT(CodeFromName(desc) == static_cast<int>(kSPRegInternalCode));
-    PrintF("%s csp:%s 0x%016" PRIx64 "%s\n",
-        clr_reg_name, clr_reg_value, xreg(31, Reg31IsStackPointer), clr_normal);
-    return true;
-  } else if (strcmp(desc, "wcsp") == 0) {
-    ASSERT(CodeFromName(desc) == static_cast<int>(kSPRegInternalCode));
-    PrintF("%s wcsp:%s 0x%08" PRIx32 "%s\n",
-        clr_reg_name, clr_reg_value, wreg(31, Reg31IsStackPointer), clr_normal);
-    return true;
-  }
-
-  int i = CodeFromName(desc);
-  STATIC_ASSERT(kNumberOfRegisters == kNumberOfFPRegisters);
-  if (i < 0 || static_cast<unsigned>(i) >= kNumberOfFPRegisters) return false;
-
-  if (desc[0] == 'v') {
-    PrintF("%s %s:%s 0x%016" PRIx64 "%s (%s%s:%s %g%s %s:%s %g%s)\n",
-        clr_fpreg_name, VRegNameForCode(i),
-        clr_fpreg_value, double_to_rawbits(dreg(i)),
-        clr_normal,
-        clr_fpreg_name, DRegNameForCode(i),
-        clr_fpreg_value, dreg(i),
-        clr_fpreg_name, SRegNameForCode(i),
-        clr_fpreg_value, sreg(i),
-        clr_normal);
-    return true;
-  } else if (desc[0] == 'd') {
-    PrintF("%s %s:%s %g%s\n",
-        clr_fpreg_name, DRegNameForCode(i),
-        clr_fpreg_value, dreg(i),
-        clr_normal);
-    return true;
-  } else if (desc[0] == 's') {
-    PrintF("%s %s:%s %g%s\n",
-        clr_fpreg_name, SRegNameForCode(i),
-        clr_fpreg_value, sreg(i),
-        clr_normal);
-    return true;
-  } else if (desc[0] == 'w') {
-    PrintF("%s %s:%s 0x%08" PRIx32 "%s\n",
-        clr_reg_name, WRegNameForCode(i), clr_reg_value, wreg(i), clr_normal);
-    return true;
-  } else {
-    // X register names have a wide variety of starting characters, but anything
-    // else will be an X register.
-    PrintF("%s %s:%s 0x%016" PRIx64 "%s\n",
-        clr_reg_name, XRegNameForCode(i), clr_reg_value, xreg(i), clr_normal);
-    return true;
-  }
-}
-
-
-void Simulator::Debug() {
-#define COMMAND_SIZE 63
-#define ARG_SIZE 255
-
-#define STR(a) #a
-#define XSTR(a) STR(a)
-
-  char cmd[COMMAND_SIZE + 1];
-  char arg1[ARG_SIZE + 1];
-  char arg2[ARG_SIZE + 1];
-  char* argv[3] = { cmd, arg1, arg2 };
-
-  // Make sure to have a proper terminating character if reaching the limit.
-  cmd[COMMAND_SIZE] = 0;
-  arg1[ARG_SIZE] = 0;
-  arg2[ARG_SIZE] = 0;
-
-  bool done = false;
-  bool cleared_log_disasm_bit = false;
-
-  while (!done) {
-    // Disassemble the next instruction to execute before doing anything else.
-    PrintInstructionsAt(pc_, 1);
-    // Read the command line.
-    char* line = ReadLine("sim> ");
-    if (line == NULL) {
-      break;
-    } else {
-      // Repeat last command by default.
-      char* last_input = last_debugger_input();
-      if (strcmp(line, "\n") == 0 && (last_input != NULL)) {
-        DeleteArray(line);
-        line = last_input;
-      } else {
-        // Update the latest command ran
-        set_last_debugger_input(line);
-      }
-
-      // Use sscanf to parse the individual parts of the command line. At the
-      // moment no command expects more than two parameters.
-      int argc = SScanF(line,
-                        "%" XSTR(COMMAND_SIZE) "s "
-                        "%" XSTR(ARG_SIZE) "s "
-                        "%" XSTR(ARG_SIZE) "s",
-                        cmd, arg1, arg2);
-
-      // stepi / si ------------------------------------------------------------
-      if ((strcmp(cmd, "si") == 0) || (strcmp(cmd, "stepi") == 0)) {
-        // We are about to execute instructions, after which by default we
-        // should increment the pc_. If it was set when reaching this debug
-        // instruction, it has not been cleared because this instruction has not
-        // completed yet. So clear it manually.
-        pc_modified_ = false;
-
-        if (argc == 1) {
-          ExecuteInstruction();
-        } else {
-          int64_t number_of_instructions_to_execute = 1;
-          GetValue(arg1, &number_of_instructions_to_execute);
-
-          set_log_parameters(log_parameters() | LOG_DISASM);
-          while (number_of_instructions_to_execute-- > 0) {
-            ExecuteInstruction();
-          }
-          set_log_parameters(log_parameters() & ~LOG_DISASM);
-          PrintF("\n");
-        }
-
-        // If it was necessary, the pc has already been updated or incremented
-        // when executing the instruction. So we do not want it to be updated
-        // again. It will be cleared when exiting.
-        pc_modified_ = true;
-
-      // next / n --------------------------------------------------------------
-      } else if ((strcmp(cmd, "next") == 0) || (strcmp(cmd, "n") == 0)) {
-        // Tell the simulator to break after the next executed BL.
-        break_on_next_ = true;
-        // Continue.
-        done = true;
-
-      // continue / cont / c ---------------------------------------------------
-      } else if ((strcmp(cmd, "continue") == 0) ||
-                 (strcmp(cmd, "cont") == 0) ||
-                 (strcmp(cmd, "c") == 0)) {
-        // Leave the debugger shell.
-        done = true;
-
-      // disassemble / disasm / di ---------------------------------------------
-      } else if (strcmp(cmd, "disassemble") == 0 ||
-                 strcmp(cmd, "disasm") == 0 ||
-                 strcmp(cmd, "di") == 0) {
-        int64_t n_of_instrs_to_disasm = 10;  // default value.
-        int64_t address = reinterpret_cast<int64_t>(pc_);  // default value.
-        if (argc >= 2) {  // disasm <n of instrs>
-          GetValue(arg1, &n_of_instrs_to_disasm);
-        }
-        if (argc >= 3) {  // disasm <n of instrs> <address>
-          GetValue(arg2, &address);
-        }
-
-        // Disassemble.
-        PrintInstructionsAt(reinterpret_cast<Instruction*>(address),
-                            n_of_instrs_to_disasm);
-        PrintF("\n");
-
-      // print / p -------------------------------------------------------------
-      } else if ((strcmp(cmd, "print") == 0) || (strcmp(cmd, "p") == 0)) {
-        if (argc == 2) {
-          if (strcmp(arg1, "all") == 0) {
-            PrintRegisters(true);
-            PrintFPRegisters(true);
-          } else {
-            if (!PrintValue(arg1)) {
-              PrintF("%s unrecognized\n", arg1);
-            }
-          }
-        } else {
-          PrintF(
-            "print <register>\n"
-            "    Print the content of a register. (alias 'p')\n"
-            "    'print all' will print all registers.\n"
-            "    Use 'printobject' to get more details about the value.\n");
-        }
-
-      // printobject / po ------------------------------------------------------
-      } else if ((strcmp(cmd, "printobject") == 0) ||
-                 (strcmp(cmd, "po") == 0)) {
-        if (argc == 2) {
-          int64_t value;
-          if (GetValue(arg1, &value)) {
-            Object* obj = reinterpret_cast<Object*>(value);
-            PrintF("%s: \n", arg1);
-#ifdef DEBUG
-            obj->PrintLn();
-#else
-            obj->ShortPrint();
-            PrintF("\n");
-#endif
-          } else {
-            PrintF("%s unrecognized\n", arg1);
-          }
-        } else {
-          PrintF("printobject <value>\n"
-                 "printobject <register>\n"
-                 "    Print details about the value. (alias 'po')\n");
-        }
-
-      // stack / mem ----------------------------------------------------------
-      } else if (strcmp(cmd, "stack") == 0 || strcmp(cmd, "mem") == 0) {
-        int64_t* cur = NULL;
-        int64_t* end = NULL;
-        int next_arg = 1;
-
-        if (strcmp(cmd, "stack") == 0) {
-          cur = reinterpret_cast<int64_t*>(jssp());
-
-        } else {  // "mem"
-          int64_t value;
-          if (!GetValue(arg1, &value)) {
-            PrintF("%s unrecognized\n", arg1);
-            continue;
-          }
-          cur = reinterpret_cast<int64_t*>(value);
-          next_arg++;
-        }
-
-        int64_t words = 0;
-        if (argc == next_arg) {
-          words = 10;
-        } else if (argc == next_arg + 1) {
-          if (!GetValue(argv[next_arg], &words)) {
-            PrintF("%s unrecognized\n", argv[next_arg]);
-            PrintF("Printing 10 double words by default");
-            words = 10;
-          }
-        } else {
-          UNREACHABLE();
-        }
-        end = cur + words;
-
-        while (cur < end) {
-          PrintF("  0x%016" PRIx64 ":  0x%016" PRIx64 " %10" PRId64,
-                 reinterpret_cast<uint64_t>(cur), *cur, *cur);
-          HeapObject* obj = reinterpret_cast<HeapObject*>(*cur);
-          int64_t value = *cur;
-          Heap* current_heap = v8::internal::Isolate::Current()->heap();
-          if (((value & 1) == 0) || current_heap->Contains(obj)) {
-            PrintF(" (");
-            if ((value & kSmiTagMask) == 0) {
-              STATIC_ASSERT(kSmiValueSize == 32);
-              int32_t untagged = (value >> kSmiShift) & 0xffffffff;
-              PrintF("smi %" PRId32, untagged);
-            } else {
-              obj->ShortPrint();
-            }
-            PrintF(")");
-          }
-          PrintF("\n");
-          cur++;
-        }
-
-      // trace / t -------------------------------------------------------------
-      } else if (strcmp(cmd, "trace") == 0 || strcmp(cmd, "t") == 0) {
-        if ((log_parameters() & (LOG_DISASM | LOG_REGS)) !=
-            (LOG_DISASM | LOG_REGS)) {
-          PrintF("Enabling disassembly and registers tracing\n");
-          set_log_parameters(log_parameters() | LOG_DISASM | LOG_REGS);
-        } else {
-          PrintF("Disabling disassembly and registers tracing\n");
-          set_log_parameters(log_parameters() & ~(LOG_DISASM | LOG_REGS));
-        }
-
-      // break / b -------------------------------------------------------------
-      } else if (strcmp(cmd, "break") == 0 || strcmp(cmd, "b") == 0) {
-        if (argc == 2) {
-          int64_t value;
-          if (GetValue(arg1, &value)) {
-            SetBreakpoint(reinterpret_cast<Instruction*>(value));
-          } else {
-            PrintF("%s unrecognized\n", arg1);
-          }
-        } else {
-          ListBreakpoints();
-          PrintF("Use `break <address>` to set or disable a breakpoint\n");
-        }
-
-      // gdb -------------------------------------------------------------------
-      } else if (strcmp(cmd, "gdb") == 0) {
-        PrintF("Relinquishing control to gdb.\n");
-        OS::DebugBreak();
-        PrintF("Regaining control from gdb.\n");
-
-      // sysregs ---------------------------------------------------------------
-      } else if (strcmp(cmd, "sysregs") == 0) {
-        PrintSystemRegisters();
-
-      // help / h --------------------------------------------------------------
-      } else if (strcmp(cmd, "help") == 0 || strcmp(cmd, "h") == 0) {
-        PrintF(
-          "stepi / si\n"
-          "    stepi <n>\n"
-          "    Step <n> instructions.\n"
-          "next / n\n"
-          "    Continue execution until a BL instruction is reached.\n"
-          "    At this point a breakpoint is set just after this BL.\n"
-          "    Then execution is resumed. It will probably later hit the\n"
-          "    breakpoint just set.\n"
-          "continue / cont / c\n"
-          "    Continue execution from here.\n"
-          "disassemble / disasm / di\n"
-          "    disassemble <n> <address>\n"
-          "    Disassemble <n> instructions from current <address>.\n"
-          "    By default <n> is 20 and <address> is the current pc.\n"
-          "print / p\n"
-          "    print <register>\n"
-          "    Print the content of a register.\n"
-          "    'print all' will print all registers.\n"
-          "    Use 'printobject' to get more details about the value.\n"
-          "printobject / po\n"
-          "    printobject <value>\n"
-          "    printobject <register>\n"
-          "    Print details about the value.\n"
-          "stack\n"
-          "    stack [<words>]\n"
-          "    Dump stack content, default dump 10 words\n"
-          "mem\n"
-          "    mem <address> [<words>]\n"
-          "    Dump memory content, default dump 10 words\n"
-          "trace / t\n"
-          "    Toggle disassembly and register tracing\n"
-          "break / b\n"
-          "    break : list all breakpoints\n"
-          "    break <address> : set / enable / disable a breakpoint.\n"
-          "gdb\n"
-          "    Enter gdb.\n"
-          "sysregs\n"
-          "    Print all system registers (including NZCV).\n");
-      } else {
-        PrintF("Unknown command: %s\n", cmd);
-        PrintF("Use 'help' for more information.\n");
-      }
-    }
-    if (cleared_log_disasm_bit == true) {
-      set_log_parameters(log_parameters_ | LOG_DISASM);
-    }
-  }
-}
-
-
-void Simulator::VisitException(Instruction* instr) {
-  switch (instr->Mask(ExceptionMask)) {
-    case HLT: {
-      if (instr->ImmException() == kImmExceptionIsDebug) {
-        // Read the arguments encoded inline in the instruction stream.
-        uint32_t code;
-        uint32_t parameters;
-
-        memcpy(&code,
-               pc_->InstructionAtOffset(kDebugCodeOffset),
-               sizeof(code));
-        memcpy(&parameters,
-               pc_->InstructionAtOffset(kDebugParamsOffset),
-               sizeof(parameters));
-        char const *message =
-            reinterpret_cast<char const*>(
-                pc_->InstructionAtOffset(kDebugMessageOffset));
-
-        // Always print something when we hit a debug point that breaks.
-        // We are going to break, so printing something is not an issue in
-        // terms of speed.
-        if (FLAG_trace_sim_messages || FLAG_trace_sim || (parameters & BREAK)) {
-          if (message != NULL) {
-            PrintF("%sDebugger hit %d: %s%s%s\n",
-                   clr_debug_number,
-                   code,
-                   clr_debug_message,
-                   message,
-                   clr_normal);
-          } else {
-            PrintF("%sDebugger hit %d.%s\n",
-                   clr_debug_number,
-                   code,
-                   clr_normal);
-          }
-        }
-
-        // Other options.
-        switch (parameters & kDebuggerTracingDirectivesMask) {
-          case TRACE_ENABLE:
-            set_log_parameters(log_parameters() | parameters);
-            if (parameters & LOG_SYS_REGS) { PrintSystemRegisters(); }
-            if (parameters & LOG_REGS) { PrintRegisters(); }
-            if (parameters & LOG_FP_REGS) { PrintFPRegisters(); }
-            break;
-          case TRACE_DISABLE:
-            set_log_parameters(log_parameters() & ~parameters);
-            break;
-          case TRACE_OVERRIDE:
-            set_log_parameters(parameters);
-            break;
-          default:
-            // We don't support a one-shot LOG_DISASM.
-            ASSERT((parameters & LOG_DISASM) == 0);
-            // Don't print information that is already being traced.
-            parameters &= ~log_parameters();
-            // Print the requested information.
-            if (parameters & LOG_SYS_REGS) PrintSystemRegisters(true);
-            if (parameters & LOG_REGS) PrintRegisters(true);
-            if (parameters & LOG_FP_REGS) PrintFPRegisters(true);
-        }
-
-        // The stop parameters are inlined in the code. Skip them:
-        //  - Skip to the end of the message string.
-        size_t size = kDebugMessageOffset + strlen(message) + 1;
-        pc_ = pc_->InstructionAtOffset(RoundUp(size, kInstructionSize));
-        //  - Verify that the unreachable marker is present.
-        ASSERT(pc_->Mask(ExceptionMask) == HLT);
-        ASSERT(pc_->ImmException() ==  kImmExceptionIsUnreachable);
-        //  - Skip past the unreachable marker.
-        set_pc(pc_->following());
-
-        // Check if the debugger should break.
-        if (parameters & BREAK) Debug();
-
-      } else if (instr->ImmException() == kImmExceptionIsRedirectedCall) {
-        DoRuntimeCall(instr);
-      } else if (instr->ImmException() == kImmExceptionIsPrintf) {
-        // Read the argument encoded inline in the instruction stream.
-        uint32_t type;
-        memcpy(&type,
-               pc_->InstructionAtOffset(kPrintfTypeOffset),
-               sizeof(type));
-
-        const char* format = reg<const char*>(0);
-
-        // Pass all of the relevant PCS registers onto printf. It doesn't
-        // matter if we pass too many as the extra ones won't be read.
-        int result;
-        fputs(clr_printf, stream_);
-        if (type == CPURegister::kRegister) {
-          result = fprintf(stream_, format,
-                           xreg(1), xreg(2), xreg(3), xreg(4),
-                           xreg(5), xreg(6), xreg(7));
-        } else if (type == CPURegister::kFPRegister) {
-          result = fprintf(stream_, format,
-                           dreg(0), dreg(1), dreg(2), dreg(3),
-                           dreg(4), dreg(5), dreg(6), dreg(7));
-        } else {
-          ASSERT(type == CPURegister::kNoRegister);
-          result = fprintf(stream_, "%s", format);
-        }
-        fputs(clr_normal, stream_);
-
-#ifdef DEBUG
-        CorruptAllCallerSavedCPURegisters();
-#endif
-
-        set_xreg(0, result);
-
-        // The printf parameters are inlined in the code, so skip them.
-        set_pc(pc_->InstructionAtOffset(kPrintfLength));
-
-        // Set LR as if we'd just called a native printf function.
-        set_lr(pc());
-
-      } else if (instr->ImmException() == kImmExceptionIsUnreachable) {
-        fprintf(stream_, "Hit UNREACHABLE marker at PC=%p.\n",
-                reinterpret_cast<void*>(pc_));
-        abort();
-
-      } else {
-        OS::DebugBreak();
-      }
-      break;
-    }
-
-    default:
-      UNIMPLEMENTED();
-  }
-}
-
-#endif  // USE_SIMULATOR
-
-} }  // namespace v8::internal
-
-#endif  // V8_TARGET_ARCH_A64