text: // Copyright 2012 the V8 project authors. All rights reserved.
  // Use of this source code is governed by a BSD-style license that can be
  // found in the LICENSE file.
  
  #if V8_TARGET_ARCH_X64
  
  #include "src/base/bits.h"
  #include "src/base/division-by-constant.h"
  #include "src/base/utils/random-number-generator.h"
  #include "src/codegen/callable.h"
  #include "src/codegen/code-factory.h"
  #include "src/codegen/external-reference-table.h"
  #include "src/codegen/macro-assembler.h"
  #include "src/codegen/register-configuration.h"
  #include "src/codegen/string-constants.h"
  #include "src/codegen/x64/assembler-x64.h"
  #include "src/common/globals.h"
  #include "src/debug/debug.h"
  #include "src/execution/frames-inl.h"
  #include "src/heap/heap-inl.h"  // For MemoryChunk.
  #include "src/init/bootstrapper.h"
  #include "src/logging/counters.h"
  #include "src/objects/objects-inl.h"
  #include "src/objects/smi.h"
  #include "src/snapshot/embedded/embedded-data.h"
  #include "src/snapshot/snapshot.h"
  
  // Satisfy cpplint check, but don't include platform-specific header. It is
  // included recursively via macro-assembler.h.
  #if 0
  #include "src/codegen/x64/macro-assembler-x64.h"
  #endif
  
  namespace v8 {
  namespace internal {
  
  Operand StackArgumentsAccessor::GetArgumentOperand(int index) {
    DCHECK_GE(index, 0);
    int receiver = (receiver_mode_ == ARGUMENTS_CONTAIN_RECEIVER) ? 1 : 0;
    int displacement_to_last_argument =
        base_reg_ == rsp ? kPCOnStackSize : kFPOnStackSize + kPCOnStackSize;
    displacement_to_last_argument += extra_displacement_to_last_argument_;
    if (argument_count_reg_ == no_reg) {
      // argument[0] is at base_reg_ + displacement_to_last_argument +
      // (argument_count_immediate_ + receiver - 1) * kSystemPointerSize.
      DCHECK_GT(argument_count_immediate_ + receiver, 0);
      return Operand(base_reg_,
                     displacement_to_last_argument +
                         (argument_count_immediate_ + receiver - 1 - index) *
                             kSystemPointerSize);
    } else {
      // argument[0] is at base_reg_ + displacement_to_last_argument +
      // argument_count_reg_ * times_system_pointer_size + (receiver - 1) *
      // kSystemPointerSize.
      return Operand(base_reg_, argument_count_reg_, times_system_pointer_size,
                     displacement_to_last_argument +
                         (receiver - 1 - index) * kSystemPointerSize);
    }
  }
  
  StackArgumentsAccessor::StackArgumentsAccessor(
      Register base_reg, const ParameterCount& parameter_count,
      StackArgumentsAccessorReceiverMode receiver_mode,
      int extra_displacement_to_last_argument)
      : base_reg_(base_reg),
        argument_count_reg_(parameter_count.is_reg() ? parameter_count.reg()
                                                     : no_reg),
        argument_count_immediate_(
            parameter_count.is_immediate() ? parameter_count.immediate() : 0),
        receiver_mode_(receiver_mode),
        extra_displacement_to_last_argument_(
            extra_displacement_to_last_argument) {}
  
  void MacroAssembler::Load(Register destination, ExternalReference source) {
    if (root_array_available_ && options().enable_root_array_delta_access) {
      intptr_t delta = RootRegisterOffsetForExternalReference(isolate(), source);
      if (is_int32(delta)) {
        movq(destination, Operand(kRootRegister, static_cast<int32_t>(delta)));
        return;
      }
    }
    // Safe code.
    if (destination == rax && !options().isolate_independent_code) {
      load_rax(source);
    } else {
      movq(destination, ExternalReferenceAsOperand(source));
    }
  }
  
  void MacroAssembler::Store(ExternalReference destination, Register source) {
    if (root_array_available_ && options().enable_root_array_delta_access) {
      intptr_t delta =
          RootRegisterOffsetForExternalReference(isolate(), destination);
      if (is_int32(delta)) {
        movq(Operand(kRootRegister, static_cast<int32_t>(delta)), source);
        return;
      }
    }
    // Safe code.
    if (source == rax && !options().isolate_independent_code) {
      store_rax(destination);
    } else {
      movq(ExternalReferenceAsOperand(destination), source);
    }
  }
  
  void TurboAssembler::LoadFromConstantsTable(Register destination,
                                              int constant_index) {
    DCHECK(RootsTable::IsImmortalImmovable(RootIndex::kBuiltinsConstantsTable));
    LoadRoot(destination, RootIndex::kBuiltinsConstantsTable);
    LoadTaggedPointerField(
        destination,
        FieldOperand(destination, FixedArray::OffsetOfElementAt(constant_index)));
  }
  
  void TurboAssembler::LoadRootRegisterOffset(Register destination,
                                              intptr_t offset) {
    DCHECK(is_int32(offset));
    if (offset == 0) {
      Move(destination, kRootRegister);
    } else {
      leaq(destination, Operand(kRootRegister, static_cast<int32_t>(offset)));
    }
  }
  
  void TurboAssembler::LoadRootRelative(Register destination, int32_t offset) {
    movq(destination, Operand(kRootRegister, offset));
  }
  
  void TurboAssembler::LoadAddress(Register destination,
                                   ExternalReference source) {
    if (root_array_available_ && options().enable_root_array_delta_access) {
      intptr_t delta = RootRegisterOffsetForExternalReference(isolate(), source);
      if (is_int32(delta)) {
        leaq(destination, Operand(kRootRegister, static_cast<int32_t>(delta)));
        return;
      }
    }
    // Safe code.
    if (FLAG_embedded_builtins) {
      if (root_array_available_ && options().isolate_independent_code) {
        IndirectLoadExternalReference(destination, source);
        return;
      }
    }
    Move(destination, source);
  }
  
  Operand TurboAssembler::ExternalReferenceAsOperand(ExternalReference reference,
                                                     Register scratch) {
    if (root_array_available_ && options().enable_root_array_delta_access) {
      int64_t delta =
          RootRegisterOffsetForExternalReference(isolate(), reference);
      if (is_int32(delta)) {
        return Operand(kRootRegister, static_cast<int32_t>(delta));
      }
    }
    if (root_array_available_ && options().isolate_independent_code) {
      if (IsAddressableThroughRootRegister(isolate(), reference)) {
        // Some external references can be efficiently loaded as an offset from
        // kRootRegister.
        intptr_t offset =
            RootRegisterOffsetForExternalReference(isolate(), reference);
        CHECK(is_int32(offset));
        return Operand(kRootRegister, static_cast<int32_t>(offset));
      } else {
        // Otherwise, do a memory load from the external reference table.
        movq(scratch, Operand(kRootRegister,
                              RootRegisterOffsetForExternalReferenceTableEntry(
                                  isolate(), reference)));
        return Operand(scratch, 0);
      }
    }
    Move(scratch, reference);
    return Operand(scratch, 0);
  }
  
  void MacroAssembler::PushAddress(ExternalReference source) {
    LoadAddress(kScratchRegister, source);
    Push(kScratchRegister);
  }
  
  void TurboAssembler::LoadRoot(Register destination, RootIndex index) {
    DCHECK(root_array_available_);
    movq(destination,
         Operand(kRootRegister, RootRegisterOffsetForRootIndex(index)));
  }
  
  void MacroAssembler::PushRoot(RootIndex index) {
    DCHECK(root_array_available_);
    Push(Operand(kRootRegister, RootRegisterOffsetForRootIndex(index)));
  }
  
  void TurboAssembler::CompareRoot(Register with, RootIndex index) {
    DCHECK(root_array_available_);
    if (IsInRange(index, RootIndex::kFirstStrongOrReadOnlyRoot,
                  RootIndex::kLastStrongOrReadOnlyRoot)) {
      cmp_tagged(with,
                 Operand(kRootRegister, RootRegisterOffsetForRootIndex(index)));
    } else {
      // Some smi roots contain system pointer size values like stack limits.
      cmpq(with, Operand(kRootRegister, RootRegisterOffsetForRootIndex(index)));
    }
  }
  
  void TurboAssembler::CompareRoot(Operand with, RootIndex index) {
    DCHECK(root_array_available_);
    DCHECK(!with.AddressUsesRegister(kScratchRegister));
    LoadRoot(kScratchRegister, index);
    if (IsInRange(index, RootIndex::kFirstStrongOrReadOnlyRoot,
                  RootIndex::kLastStrongOrReadOnlyRoot)) {
      cmp_tagged(with, kScratchRegister);
    } else {
      // Some smi roots contain system pointer size values like stack limits.
      cmpq(with, kScratchRegister);
    }
  }
  
  void TurboAssembler::LoadTaggedPointerField(Register destination,
                                              Operand field_operand) {
  #ifdef V8_COMPRESS_POINTERS
    DecompressTaggedPointer(destination, field_operand);
  #else
    mov_tagged(destination, field_operand);
  #endif
  }
  
  void TurboAssembler::LoadAnyTaggedField(Register destination,
                                          Operand field_operand,
                                          Register scratch) {
  #ifdef V8_COMPRESS_POINTERS
    DecompressAnyTagged(destination, field_operand, scratch);
  #else
    mov_tagged(destination, field_operand);
  #endif
  }
  
  void TurboAssembler::PushTaggedPointerField(Operand field_operand,
                                              Register scratch) {
  #ifdef V8_COMPRESS_POINTERS
    DCHECK(!field_operand.AddressUsesRegister(scratch));
    DecompressTaggedPointer(scratch, field_operand);
    Push(scratch);
  #else
    Push(field_operand);
  #endif
  }
  
  void TurboAssembler::PushTaggedAnyField(Operand field_operand,
                                          Register scratch1, Register scratch2) {
  #ifdef V8_COMPRESS_POINTERS
    DCHECK(!AreAliased(scratch1, scratch2));
    DCHECK(!field_operand.AddressUsesRegister(scratch1));
    DCHECK(!field_operand.AddressUsesRegister(scratch2));
    DecompressAnyTagged(scratch1, field_operand, scratch2);
    Push(scratch1);
  #else
    Push(field_operand);
  #endif
  }
  
  void TurboAssembler::SmiUntagField(Register dst, Operand src) {
    SmiUntag(dst, src);
  }
  
  void TurboAssembler::StoreTaggedField(Operand dst_field_operand,
                                        Immediate value) {
  #ifdef V8_COMPRESS_POINTERS
    RecordComment("[ StoreTagged");
    movl(dst_field_operand, value);
    RecordComment("]");
  #else
    movq(dst_field_operand, value);
  #endif
  }
  
  void TurboAssembler::StoreTaggedField(Operand dst_field_operand,
                                        Register value) {
  #ifdef V8_COMPRESS_POINTERS
    RecordComment("[ StoreTagged");
    movl(dst_field_operand, value);
    RecordComment("]");
  #else
    movq(dst_field_operand, value);
  #endif
  }
  
  void TurboAssembler::DecompressTaggedSigned(Register destination,
                                              Operand field_operand) {
    RecordComment("[ DecompressTaggedSigned");
    movsxlq(destination, field_operand);
    RecordComment("]");
  }
  
  void TurboAssembler::DecompressTaggedSigned(Register destination,
                                              Register source) {
    RecordComment("[ DecompressTaggedSigned");
    movsxlq(destination, source);
    RecordComment("]");
  }
  
  void TurboAssembler::DecompressTaggedPointer(Register destination,
                                               Operand field_operand) {
    RecordComment("[ DecompressTaggedPointer");
    movsxlq(destination, field_operand);
    addq(destination, kRootRegister);
    RecordComment("]");
  }
  
  void TurboAssembler::DecompressTaggedPointer(Register destination,
                                               Register source) {
    RecordComment("[ DecompressTaggedPointer");
    movsxlq(destination, source);
    addq(destination, kRootRegister);
    RecordComment("]");
  }
  
  void TurboAssembler::DecompressRegisterAnyTagged(Register destination,
                                                   Register scratch) {
    if (kUseBranchlessPtrDecompressionInGeneratedCode) {
      // Branchlessly compute |masked_root|:
      // masked_root = HAS_SMI_TAG(destination) ? 0 : kRootRegister;
      STATIC_ASSERT((kSmiTagSize == 1) && (kSmiTag < 32));
      Register masked_root = scratch;
      movl(masked_root, destination);
      andl(masked_root, Immediate(kSmiTagMask));
      negq(masked_root);
      andq(masked_root, kRootRegister);
      // Now this add operation will either leave the value unchanged if it is
      // a smi or add the isolate root if it is a heap object.
      addq(destination, masked_root);
    } else {
      Label done;
      JumpIfSmi(destination, &done);
      addq(destination, kRootRegister);
      bind(&done);
    }
  }
  
  void TurboAssembler::DecompressAnyTagged(Register destination,
                                           Operand field_operand,
                                           Register scratch) {
    DCHECK(!AreAliased(destination, scratch));
    RecordComment("[ DecompressAnyTagged");
    movsxlq(destination, field_operand);
    DecompressRegisterAnyTagged(destination, scratch);
    RecordComment("]");
  }
  
  void TurboAssembler::DecompressAnyTagged(Register destination, Register source,
                                           Register scratch) {
    DCHECK(!AreAliased(destination, scratch));
    RecordComment("[ DecompressAnyTagged");
    movsxlq(destination, source);
    DecompressRegisterAnyTagged(destination, scratch);
    RecordComment("]");
  }
  
  void MacroAssembler::RecordWriteField(Register object, int offset,
                                        Register value, Register dst,
                                        SaveFPRegsMode save_fp,
                                        RememberedSetAction remembered_set_action,
                                        SmiCheck smi_check) {
    // First, check if a write barrier is even needed. The tests below
    // catch stores of Smis.
    Label done;
  
    // Skip barrier if writing a smi.
    if (smi_check == INLINE_SMI_CHECK) {
      JumpIfSmi(value, &done);
    }
  
    // Although the object register is tagged, the offset is relative to the start
    // of the object, so the offset must be a multiple of kTaggedSize.
    DCHECK(IsAligned(offset, kTaggedSize));
  
    leaq(dst, FieldOperand(object, offset));
    if (emit_debug_code()) {
      Label ok;
      testb(dst, Immediate(kTaggedSize - 1));
      j(zero, &ok, Label::kNear);
      int3();
      bind(&ok);
    }
  
    RecordWrite(object, dst, value, save_fp, remembered_set_action,
                OMIT_SMI_CHECK);
  
    bind(&done);
  
    // Clobber clobbered input registers when running with the debug-code flag
    // turned on to provoke errors.
    if (emit_debug_code()) {
      Move(value, kZapValue, RelocInfo::NONE);
      Move(dst, kZapValue, RelocInfo::NONE);
    }
  }
  
  void TurboAssembler::SaveRegisters(RegList registers) {
    DCHECK_GT(NumRegs(registers), 0);
    for (int i = 0; i < Register::kNumRegisters; ++i) {
      if ((registers >> i) & 1u) {
        pushq(Register::from_code(i));
      }
    }
  }
  
  void TurboAssembler::RestoreRegisters(RegList registers) {
    DCHECK_GT(NumRegs(registers), 0);
    for (int i = Register::kNumRegisters - 1; i >= 0; --i) {
      if ((registers >> i) & 1u) {
        popq(Register::from_code(i));
      }
    }
  }
  
  void TurboAssembler::CallEphemeronKeyBarrier(Register object, Register address,
                                               SaveFPRegsMode fp_mode) {
    EphemeronKeyBarrierDescriptor descriptor;
    RegList registers = descriptor.allocatable_registers();
  
    SaveRegisters(registers);
  
    Register object_parameter(
        descriptor.GetRegisterParameter(EphemeronKeyBarrierDescriptor::kObject));
    Register slot_parameter(descriptor.GetRegisterParameter(
        EphemeronKeyBarrierDescriptor::kSlotAddress));
    Register fp_mode_parameter(
        descriptor.GetRegisterParameter(EphemeronKeyBarrierDescriptor::kFPMode));
  
    MovePair(slot_parameter, address, object_parameter, object);
    Smi smi_fm = Smi::FromEnum(fp_mode);
    Move(fp_mode_parameter, smi_fm);
    Call(isolate()->builtins()->builtin_handle(Builtins::kEphemeronKeyBarrier),
         RelocInfo::CODE_TARGET);
  
    RestoreRegisters(registers);
  }
  
  void TurboAssembler::CallRecordWriteStub(
      Register object, Register address,
      RememberedSetAction remembered_set_action, SaveFPRegsMode fp_mode) {
    CallRecordWriteStub(
        object, address, remembered_set_action, fp_mode,
        isolate()->builtins()->builtin_handle(Builtins::kRecordWrite),
        kNullAddress);
  }
  
  void TurboAssembler::CallRecordWriteStub(
      Register object, Register address,
      RememberedSetAction remembered_set_action, SaveFPRegsMode fp_mode,
      Address wasm_target) {
    CallRecordWriteStub(object, address, remembered_set_action, fp_mode,
                        Handle<Code>::null(), wasm_target);
  }
  
  void TurboAssembler::CallRecordWriteStub(
      Register object, Register address,
      RememberedSetAction remembered_set_action, SaveFPRegsMode fp_mode,
      Handle<Code> code_target, Address wasm_target) {
    DCHECK_NE(code_target.is_null(), wasm_target == kNullAddress);
  
    RecordWriteDescriptor descriptor;
    RegList registers = descriptor.allocatable_registers();
  
    SaveRegisters(registers);
  
    Register object_parameter(
        descriptor.GetRegisterParameter(RecordWriteDescriptor::kObject));
    Register slot_parameter(
        descriptor.GetRegisterParameter(RecordWriteDescriptor::kSlot));
    Register remembered_set_parameter(
        descriptor.GetRegisterParameter(RecordWriteDescriptor::kRememberedSet));
    Register fp_mode_parameter(
        descriptor.GetRegisterParameter(RecordWriteDescriptor::kFPMode));
  
    // Prepare argument registers for calling RecordWrite
    // slot_parameter   <= address
    // object_parameter <= object
    MovePair(slot_parameter, address, object_parameter, object);
  
    Smi smi_rsa = Smi::FromEnum(remembered_set_action);
    Smi smi_fm = Smi::FromEnum(fp_mode);
    Move(remembered_set_parameter, smi_rsa);
    if (smi_rsa != smi_fm) {
      Move(fp_mode_parameter, smi_fm);
    } else {
      movq(fp_mode_parameter, remembered_set_parameter);
    }
    if (code_target.is_null()) {
      // Use {near_call} for direct Wasm call within a module.
      near_call(wasm_target, RelocInfo::WASM_STUB_CALL);
    } else {
      Call(code_target, RelocInfo::CODE_TARGET);
    }
  
    RestoreRegisters(registers);
  }
  
  void MacroAssembler::RecordWrite(Register object, Register address,
                                   Register value, SaveFPRegsMode fp_mode,
                                   RememberedSetAction remembered_set_action,
                                   SmiCheck smi_check) {
    DCHECK(object != value);
    DCHECK(object != address);
    DCHECK(value != address);
    AssertNotSmi(object);
  
    if (remembered_set_action == OMIT_REMEMBERED_SET &&
        !FLAG_incremental_marking) {
      return;
    }
  
    if (emit_debug_code()) {
      Label ok;
      cmp_tagged(value, Operand(address, 0));
      j(equal, &ok, Label::kNear);
      int3();
      bind(&ok);
    }
  
    // First, check if a write barrier is even needed. The tests below
    // catch stores of smis and stores into the young generation.
    Label done;
  
    if (smi_check == INLINE_SMI_CHECK) {
      // Skip barrier if writing a smi.
      JumpIfSmi(value, &done);
    }
  
    CheckPageFlag(value,
                  value,  // Used as scratch.
                  MemoryChunk::kPointersToHereAreInterestingMask, zero, &done,
                  Label::kNear);
  
    CheckPageFlag(object,
                  value,  // Used as scratch.
                  MemoryChunk::kPointersFromHereAreInterestingMask, zero, &done,
                  Label::kNear);
  
    CallRecordWriteStub(object, address, remembered_set_action, fp_mode);
  
    bind(&done);
  
    // Clobber clobbered registers when running with the debug-code flag
    // turned on to provoke errors.
    if (emit_debug_code()) {
      Move(address, kZapValue, RelocInfo::NONE);
      Move(value, kZapValue, RelocInfo::NONE);
    }
  }
  
  void TurboAssembler::Assert(Condition cc, AbortReason reason) {
    if (emit_debug_code()) Check(cc, reason);
  }
  
  void TurboAssembler::AssertUnreachable(AbortReason reason) {
    if (emit_debug_code()) Abort(reason);
  }
  
  void TurboAssembler::Check(Condition cc, AbortReason reason) {
    Label L;
    j(cc, &L, Label::kNear);
    Abort(reason);
    // Control will not return here.
    bind(&L);
  }
  
  void TurboAssembler::CheckStackAlignment() {
    int frame_alignment = base::OS::ActivationFrameAlignment();
    int frame_alignment_mask = frame_alignment - 1;
    if (frame_alignment > kSystemPointerSize) {
      DCHECK(base::bits::IsPowerOfTwo(frame_alignment));
      Label alignment_as_expected;
      testq(rsp, Immediate(frame_alignment_mask));
      j(zero, &alignment_as_expected, Label::kNear);
      // Abort if stack is not aligned.
      int3();
      bind(&alignment_as_expected);
    }
  }
  
  void TurboAssembler::Abort(AbortReason reason) {
  #ifdef DEBUG
    const char* msg = GetAbortReason(reason);
    RecordComment("Abort message: ");
    RecordComment(msg);
  #endif
  
    // Avoid emitting call to builtin if requested.
    if (trap_on_abort()) {
      int3();
      return;
    }
  
    if (should_abort_hard()) {
      // We don't care if we constructed a frame. Just pretend we did.
      FrameScope assume_frame(this, StackFrame::NONE);
      movl(arg_reg_1, Immediate(static_cast<int>(reason)));
      PrepareCallCFunction(1);
      LoadAddress(rax, ExternalReference::abort_with_reason());
      call(rax);
      return;
    }
  
    Move(rdx, Smi::FromInt(static_cast<int>(reason)));
  
    if (!has_frame()) {
      // We don't actually want to generate a pile of code for this, so just
      // claim there is a stack frame, without generating one.
      FrameScope scope(this, StackFrame::NONE);
      Call(BUILTIN_CODE(isolate(), Abort), RelocInfo::CODE_TARGET);
    } else {
      Call(BUILTIN_CODE(isolate(), Abort), RelocInfo::CODE_TARGET);
    }
    // Control will not return here.
    int3();
  }
  
  void TurboAssembler::CallRuntimeWithCEntry(Runtime::FunctionId fid,
                                             Register centry) {
    const Runtime::Function* f = Runtime::FunctionForId(fid);
    // TODO(1236192): Most runtime routines don't need the number of
    // arguments passed in because it is constant. At some point we
    // should remove this need and make the runtime routine entry code
    // smarter.
    Set(rax, f->nargs);
    LoadAddress(rbx, ExternalReference::Create(f));
    DCHECK(!AreAliased(centry, rax, rbx));
    DCHECK(centry == rcx);
    CallCodeObject(centry);
  }
  
  void MacroAssembler::CallRuntime(const Runtime::Function* f, int num_arguments,
                                   SaveFPRegsMode save_doubles) {
    // If the expected number of arguments of the runtime function is
    // constant, we check that the actual number of arguments match the
    // expectation.
    CHECK(f->nargs < 0 || f->nargs == num_arguments);
  
    // TODO(1236192): Most runtime routines don't need the number of
    // arguments passed in because it is constant. At some point we
    // should remove this need and make the runtime routine entry code
    // smarter.
    Set(rax, num_arguments);
    LoadAddress(rbx, ExternalReference::Create(f));
    Handle<Code> code =
        CodeFactory::CEntry(isolate(), f->result_size, save_doubles);
    Call(code, RelocInfo::CODE_TARGET);
  }
  
  void MacroAssembler::TailCallRuntime(Runtime::FunctionId fid) {
    // ----------- S t a t e -------------
    //  -- rsp[0]                 : return address
    //  -- rsp[8]                 : argument num_arguments - 1
    //  ...
    //  -- rsp[8 * num_arguments] : argument 0 (receiver)
    //
    //  For runtime functions with variable arguments:
    //  -- rax                    : number of  arguments
    // -----------------------------------
  
    const Runtime::Function* function = Runtime::FunctionForId(fid);
    DCHECK_EQ(1, function->result_size);
    if (function->nargs >= 0) {
      Set(rax, function->nargs);
    }
    JumpToExternalReference(ExternalReference::Create(fid));
  }
  
  void MacroAssembler::JumpToExternalReference(const ExternalReference& ext,
                                               bool builtin_exit_frame) {
    // Set the entry point and jump to the C entry runtime stub.
    LoadAddress(rbx, ext);
    Handle<Code> code = CodeFactory::CEntry(isolate(), 1, kDontSaveFPRegs,
                                            kArgvOnStack, builtin_exit_frame);
    Jump(code, RelocInfo::CODE_TARGET);
  }
  
  static constexpr Register saved_regs[] = {rax, rcx, rdx, rbx, rbp, rsi,
                                            rdi, r8,  r9,  r10, r11};
  
  static constexpr int kNumberOfSavedRegs = sizeof(saved_regs) / sizeof(Register);
  
  int TurboAssembler::RequiredStackSizeForCallerSaved(SaveFPRegsMode fp_mode,
                                                      Register exclusion1,
                                                      Register exclusion2,
                                                      Register exclusion3) const {
    int bytes = 0;
    for (int i = 0; i < kNumberOfSavedRegs; i++) {
      Register reg = saved_regs[i];
      if (reg != exclusion1 && reg != exclusion2 && reg != exclusion3) {
        bytes += kSystemPointerSize;
      }
    }
  
    // R12 to r15 are callee save on all platforms.
    if (fp_mode == kSaveFPRegs) {
      bytes += kDoubleSize * XMMRegister::kNumRegisters;
    }
  
    return bytes;
  }
  
  int TurboAssembler::PushCallerSaved(SaveFPRegsMode fp_mode, Register exclusion1,
                                      Register exclusion2, Register exclusion3) {
    // We don't allow a GC during a store buffer overflow so there is no need to
    // store the registers in any particular way, but we do have to store and
    // restore them.
    int bytes = 0;
    for (int i = 0; i < kNumberOfSavedRegs; i++) {
      Register reg = saved_regs[i];
      if (reg != exclusion1 && reg != exclusion2 && reg != exclusion3) {
        pushq(reg);
        bytes += kSystemPointerSize;
      }
    }
  
    // R12 to r15 are callee save on all platforms.
    if (fp_mode == kSaveFPRegs) {
      int delta = kDoubleSize * XMMRegister::kNumRegisters;
      AllocateStackSpace(delta);
      for (int i = 0; i < XMMRegister::kNumRegisters; i++) {
        XMMRegister reg = XMMRegister::from_code(i);
        Movsd(Operand(rsp, i * kDoubleSize), reg);
      }
      bytes += delta;
    }
  
    return bytes;
  }
  
  int TurboAssembler::PopCallerSaved(SaveFPRegsMode fp_mode, Register exclusion1,
                                     Register exclusion2, Register exclusion3) {
    int bytes = 0;
    if (fp_mode == kSaveFPRegs) {
      for (int i = 0; i < XMMRegister::kNumRegisters; i++) {
        XMMRegister reg = XMMRegister::from_code(i);
        Movsd(reg, Operand(rsp, i * kDoubleSize));
      }
      int delta = kDoubleSize * XMMRegister::kNumRegisters;
      addq(rsp, Immediate(kDoubleSize * XMMRegister::kNumRegisters));
      bytes += delta;
    }
  
    for (int i = kNumberOfSavedRegs - 1; i >= 0; i--) {
      Register reg = saved_regs[i];
      if (reg != exclusion1 && reg != exclusion2 && reg != exclusion3) {
        popq(reg);
        bytes += kSystemPointerSize;
      }
    }
  
    return bytes;
  }
  
  void TurboAssembler::Cvtss2sd(XMMRegister dst, XMMRegister src) {
    if (CpuFeatures::IsSupported(AVX)) {
      CpuFeatureScope scope(this, AVX);
      vcvtss2sd(dst, src, src);
    } else {
      cvtss2sd(dst, src);
    }
  }
  
  void TurboAssembler::Cvtss2sd(XMMRegister dst, Operand src) {
    if (CpuFeatures::IsSupported(AVX)) {
      CpuFeatureScope scope(this, AVX);
      vcvtss2sd(dst, dst, src);
    } else {
      cvtss2sd(dst, src);
    }
  }
  
  void TurboAssembler::Cvtsd2ss(XMMRegister dst, XMMRegister src) {
    if (CpuFeatures::IsSupported(AVX)) {
      CpuFeatureScope scope(this, AVX);
      vcvtsd2ss(dst, src, src);
    } else {
      cvtsd2ss(dst, src);
    }
  }
  
  void TurboAssembler::Cvtsd2ss(XMMRegister dst, Operand src) {
    if (CpuFeatures::IsSupported(AVX)) {
      CpuFeatureScope scope(this, AVX);
      vcvtsd2ss(dst, dst, src);
    } else {
      cvtsd2ss(dst, src);
    }
  }
  
  void TurboAssembler::Cvtlsi2sd(XMMRegister dst, Register src) {
    if (CpuFeatures::IsSupported(AVX)) {
      CpuFeatureScope scope(this, AVX);
      vxorpd(dst, dst, dst);
      vcvtlsi2sd(dst, dst, src);
    } else {
      xorpd(dst, dst);
      cvtlsi2sd(dst, src);
    }
  }
  
  void TurboAssembler::Cvtlsi2sd(XMMRegister dst, Operand src) {
    if (CpuFeatures::IsSupported(AVX)) {
      CpuFeatureScope scope(this, AVX);
      vxorpd(dst, dst, dst);
      vcvtlsi2sd(dst, dst, src);
    } else {
      xorpd(dst, dst);
      cvtlsi2sd(dst, src);
    }
  }
  
  void TurboAssembler::Cvtlsi2ss(XMMRegister dst, Register src) {
    if (CpuFeatures::IsSupported(AVX)) {
      CpuFeatureScope scope(this, AVX);
      vxorps(dst, dst, dst);
      vcvtlsi2ss(dst, dst, src);
    } else {
      xorps(dst, dst);
      cvtlsi2ss(dst, src);
    }
  }
  
  void TurboAssembler::Cvtlsi2ss(XMMRegister dst, Operand src) {
    if (CpuFeatures::IsSupported(AVX)) {
      CpuFeatureScope scope(this, AVX);
      vxorps(dst, dst, dst);
      vcvtlsi2ss(dst, dst, src);
    } else {
      xorps(dst, dst);
      cvtlsi2ss(dst, src);
    }
  }
  
  void TurboAssembler::Cvtqsi2ss(XMMRegister dst, Register src) {
    if (CpuFeatures::IsSupported(AVX)) {
      CpuFeatureScope scope(this, AVX);
      vxorps(dst, dst, dst);
      vcvtqsi2ss(dst, dst, src);
    } else {
      xorps(dst, dst);
      cvtqsi2ss(dst, src);
    }
  }
  
  void TurboAssembler::Cvtqsi2ss(XMMRegister dst, Operand src) {
    if (CpuFeatures::IsSupported(AVX)) {
      CpuFeatureScope scope(this, AVX);
      vxorps(dst, dst, dst);
      vcvtqsi2ss(dst, dst, src);
    } else {
      xorps(dst, dst);
      cvtqsi2ss(dst, src);
    }
  }
  
  void TurboAssembler::Cvtqsi2sd(XMMRegister dst, Register src) {
    if (CpuFeatures::IsSupported(AVX)) {
      CpuFeatureScope scope(this, AVX);
      vxorpd(dst, dst, dst);
      vcvtqsi2sd(dst, dst, src);
    } else {
      xorpd(dst, dst);
      cvtqsi2sd(dst, src);
    }
  }
  
  void TurboAssembler::Cvtqsi2sd(XMMRegister dst, Operand src) {
    if (CpuFeatures::IsSupported(AVX)) {
      CpuFeatureScope scope(this, AVX);
      vxorpd(dst, dst, dst);
      vcvtqsi2sd(dst, dst, src);
    } else {
      xorpd(dst, dst);
      cvtqsi2sd(dst, src);
    }
  }
  
  void TurboAssembler::Cvtlui2ss(XMMRegister dst, Register src) {
    // Zero-extend the 32 bit value to 64 bit.
    movl(kScratchRegister, src);
    Cvtqsi2ss(dst, kScratchRegister);
  }
  
  void TurboAssembler::Cvtlui2ss(XMMRegister dst, Operand src) {
    // Zero-extend the 32 bit value to 64 bit.
    movl(kScratchRegister, src);
    Cvtqsi2ss(dst, kScratchRegister);
  }
  
  void TurboAssembler::Cvtlui2sd(XMMRegister dst, Register src) {
    // Zero-extend the 32 bit value to 64 bit.
    movl(kScratchRegister, src);
    Cvtqsi2sd(dst, kScratchRegister);
  }
  
  void TurboAssembler::Cvtlui2sd(XMMRegister dst, Operand src) {
    // Zero-extend the 32 bit value to 64 bit.
    movl(kScratchRegister, src);
    Cvtqsi2sd(dst, kScratchRegister);
  }
  
  void TurboAssembler::Cvtqui2ss(XMMRegister dst, Register src) {
    Label done;
    Cvtqsi2ss(dst, src);
    testq(src, src);
    j(positive, &done, Label::kNear);
  
    // Compute {src/2 | (src&1)} (retain the LSB to avoid rounding errors).
    if (src != kScratchRegister) movq(kScratchRegister, src);
    shrq(kScratchRegister, Immediate(1));
    // The LSB is shifted into CF. If it is set, set the LSB in {tmp}.
    Label msb_not_set;
    j(not_carry, &msb_not_set, Label::kNear);
    orq(kScratchRegister, Immediate(1));
    bind(&msb_not_set);
    Cvtqsi2ss(dst, kScratchRegister);
    Addss(dst, dst);
    bind(&done);
  }
  
  void TurboAssembler::Cvtqui2ss(XMMRegister dst, Operand src) {
    movq(kScratchRegister, src);
    Cvtqui2ss(dst, kScratchRegister);
  }
  
  void TurboAssembler::Cvtqui2sd(XMMRegister dst, Register src) {
    Label done;
    Cvtqsi2sd(dst, src);
    testq(src, src);
    j(positive, &done, Label::kNear);
  
    // Compute {src/2 | (src&1)} (retain the LSB to avoid rounding errors).
    if (src != kScratchRegister) movq(kScratchRegister, src);
    shrq(kScratchRegister, Immediate(1));
    // The LSB is shifted into CF. If it is set, set the LSB in {tmp}.
    Label msb_not_set;
    j(not_carry, &msb_not_set, Label::kNear);
    orq(kScratchRegister, Immediate(1));
    bind(&msb_not_set);
    Cvtqsi2sd(dst, kScratchRegister);
    Addsd(dst, dst);
    bind(&done);
  }
  
  void TurboAssembler::Cvtqui2sd(XMMRegister dst, Operand src) {
    movq(kScratchRegister, src);
    Cvtqui2sd(dst, kScratchRegister);
  }
  
  void TurboAssembler::Cvttss2si(Register dst, XMMRegister src) {
    if (CpuFeatures::IsSupported(AVX)) {
      CpuFeatureScope scope(this, AVX);
      vcvttss2si(dst, src);
    } else {
      cvttss2si(dst, src);
    }
  }
  
  void TurboAssembler::Cvttss2si(Register dst, Operand src) {
    if (CpuFeatures::IsSupported(AVX)) {
      CpuFeatureScope scope(this, AVX);
      vcvttss2si(dst, src);
    } else {
      cvttss2si(dst, src);
    }
  }
  
  void TurboAssembler::Cvttsd2si(Register dst, XMMRegister src) {
    if (CpuFeatures::IsSupported(AVX)) {
      CpuFeatureScope scope(this, AVX);
      vcvttsd2si(dst, src);
    } else {
      cvttsd2si(dst, src);
    }
  }
  
  void TurboAssembler::Cvttsd2si(Register dst, Operand src) {
    if (CpuFeatures::IsSupported(AVX)) {
      CpuFeatureScope scope(this, AVX);
      vcvttsd2si(dst, src);
    } else {
      cvttsd2si(dst, src);
    }
  }
  
  void TurboAssembler::Cvttss2siq(Register dst, XMMRegister src) {
    if (CpuFeatures::IsSupported(AVX)) {
      CpuFeatureScope scope(this, AVX);
      vcvttss2siq(dst, src);
    } else {
      cvttss2siq(dst, src);
    }
  }
  
  void TurboAssembler::Cvttss2siq(Register dst, Operand src) {
    if (CpuFeatures::IsSupported(AVX)) {
      CpuFeatureScope scope(this, AVX);
      vcvttss2siq(dst, src);
    } else {
      cvttss2siq(dst, src);
    }
  }
  
  void TurboAssembler::Cvttsd2siq(Register dst, XMMRegister src) {
    if (CpuFeatures::IsSupported(AVX)) {
      CpuFeatureScope scope(this, AVX);
      vcvttsd2siq(dst, src);
    } else {
      cvttsd2siq(dst, src);
    }
  }
  
  void TurboAssembler::Cvttsd2siq(Register dst, Operand src) {
    if (CpuFeatures::IsSupported(AVX)) {
      CpuFeatureScope scope(this, AVX);
      vcvttsd2siq(dst, src);
    } else {
      cvttsd2siq(dst, src);
    }
  }
  
  namespace {
  template <typename OperandOrXMMRegister, bool is_double>
  void ConvertFloatToUint64(TurboAssembler* tasm, Register dst,
                            OperandOrXMMRegister src, Label* fail) {
    Label success;
    // There does not exist a native float-to-uint instruction, so we have to use
    // a float-to-int, and postprocess the result.
    if (is_double) {
      tasm->Cvttsd2siq(dst, src);
    } else {
      tasm->Cvttss2siq(dst, src);
    }
    // If the result of the conversion is positive, we are already done.
    tasm->testq(dst, dst);
    tasm->j(positive, &success);
    // The result of the first conversion was negative, which means that the
    // input value was not within the positive int64 range. We subtract 2^63
    // and convert it again to see if it is within the uint64 range.
    if (is_double) {
      tasm->Move(kScratchDoubleReg, -9223372036854775808.0);
      tasm->Addsd(kScratchDoubleReg, src);
      tasm->Cvttsd2siq(dst, kScratchDoubleReg);
    } else {
      tasm->Move(kScratchDoubleReg, -9223372036854775808.0f);
      tasm->Addss(kScratchDoubleReg, src);
      tasm->Cvttss2siq(dst, kScratchDoubleReg);
    }
    tasm->testq(dst, dst);
    // The only possible negative value here is 0x80000000000000000, which is
    // used on x64 to indicate an integer overflow.
    tasm->j(negative, fail ? fail : &success);
    // The input value is within uint64 range and the second conversion worked
    // successfully, but we still have to undo the subtraction we did
    // earlier.
    tasm->Set(kScratchRegister, 0x8000000000000000);
    tasm->orq(dst, kScratchRegister);
    tasm->bind(&success);
  }
  }  // namespace
  
  void TurboAssembler::Cvttsd2uiq(Register dst, Operand src, Label* success) {
    ConvertFloatToUint64<Operand, true>(this, dst, src, success);
  }
  
  void TurboAssembler::Cvttsd2uiq(Register dst, XMMRegister src, Label* success) {
    ConvertFloatToUint64<XMMRegister, true>(this, dst, src, success);
  }
  
  void TurboAssembler::Cvttss2uiq(Register dst, Operand src, Label* success) {
    ConvertFloatToUint64<Operand, false>(this, dst, src, success);
  }
  
  void TurboAssembler::Cvttss2uiq(Register dst, XMMRegister src, Label* success) {
    ConvertFloatToUint64<XMMRegister, false>(this, dst, src, success);
  }
  
  void TurboAssembler::Set(Register dst, int64_t x) {
    if (x == 0) {
      xorl(dst, dst);
    } else if (is_uint32(x)) {
      movl(dst, Immediate(static_cast<uint32_t>(x)));
    } else if (is_int32(x)) {
      movq(dst, Immediate(static_cast<int32_t>(x)));
    } else {
      movq(dst, x);
    }
  }
  
  void TurboAssembler::Set(Operand dst, intptr_t x) {
    if (is_int32(x)) {
      movq(dst, Immediate(static_cast<int32_t>(x)));
    } else {
      Set(kScratchRegister, x);
      movq(dst, kScratchRegister);
    }
  }
  
  // ----------------------------------------------------------------------------
  // Smi tagging, untagging and tag detection.
  
  Register TurboAssembler::GetSmiConstant(Smi source) {
    STATIC_ASSERT(kSmiTag == 0);
    int value = source.value();
    if (value == 0) {
      xorl(kScratchRegister, kScratchRegister);
      return kScratchRegister;
    }
    Move(kScratchRegister, source);
    return kScratchRegister;
  }
  
  void TurboAssembler::Move(Register dst, Smi source) {
    STATIC_ASSERT(kSmiTag == 0);
    int value = source.value();
    if (value == 0) {
      xorl(dst, dst);
    } else {
      Move(dst, source.ptr(), RelocInfo::NONE);
    }
  }
  
  void TurboAssembler::Move(Register dst, ExternalReference ext) {
    if (FLAG_embedded_builtins) {
      if (root_array_available_ && options().isolate_independent_code) {
        IndirectLoadExternalReference(dst, ext);
        return;
      }
    }
    movq(dst, Immediate64(ext.address(), RelocInfo::EXTERNAL_REFERENCE));
  }
  
  void MacroAssembler::SmiTag(Register dst, Register src) {
    STATIC_ASSERT(kSmiTag == 0);
    if (dst != src) {
      movq(dst, src);
    }
    DCHECK(SmiValuesAre32Bits() || SmiValuesAre31Bits());
    shlq(dst, Immediate(kSmiShift));
  }
  
  void TurboAssembler::SmiUntag(Register dst, Register src) {
    STATIC_ASSERT(kSmiTag == 0);
    if (dst != src) {
      movq(dst, src);
    }
    DCHECK(SmiValuesAre32Bits() || SmiValuesAre31Bits());
    sarq(dst, Immediate(kSmiShift));
  }
  
  void TurboAssembler::SmiUntag(Register dst, Operand src) {
    if (SmiValuesAre32Bits()) {
      movl(dst, Operand(src, kSmiShift / kBitsPerByte));
      // Sign extend to 64-bit.
      movsxlq(dst, dst);
    } else {
      DCHECK(SmiValuesAre31Bits());
  #ifdef V8_COMPRESS_POINTERS
      movsxlq(dst, src);
  #else
      movq(dst, src);
  #endif
      sarq(dst, Immediate(kSmiShift));
    }
  }
  
  void MacroAssembler::SmiCompare(Register smi1, Register smi2) {
    AssertSmi(smi1);
    AssertSmi(smi2);
    cmp_tagged(smi1, smi2);
  }
  
  void MacroAssembler::SmiCompare(Register dst, Smi src) {
    AssertSmi(dst);
    Cmp(dst, src);
  }
  
  void MacroAssembler::Cmp(Register dst, Smi src) {
    DCHECK_NE(dst, kScratchRegister);
    if (src.value() == 0) {
      test_tagged(dst, dst);
    } else {
      Register constant_reg = GetSmiConstant(src);
      cmp_tagged(dst, constant_reg);
    }
  }
  
  void MacroAssembler::SmiCompare(Register dst, Operand src) {
    AssertSmi(dst);
    AssertSmi(src);
    cmp_tagged(dst, src);
  }
  
  void MacroAssembler::SmiCompare(Operand dst, Register src) {
    AssertSmi(dst);
    AssertSmi(src);
    cmp_tagged(dst, src);
  }
  
  void MacroAssembler::SmiCompare(Operand dst, Smi src) {
    AssertSmi(dst);
    if (SmiValuesAre32Bits()) {
      cmpl(Operand(dst, kSmiShift / kBitsPerByte), Immediate(src.value()));
    } else {
      DCHECK(SmiValuesAre31Bits());
      cmpl(dst, Immediate(src));
    }
  }
  
  void MacroAssembler::Cmp(Operand dst, Smi src) {
    // The Operand cannot use the smi register.
    Register smi_reg = GetSmiConstant(src);
    DCHECK(!dst.AddressUsesRegister(smi_reg));
    cmp_tagged(dst, smi_reg);
  }
  
  Condition TurboAssembler::CheckSmi(Register src) {
    STATIC_ASSERT(kSmiTag == 0);
    testb(src, Immediate(kSmiTagMask));
    return zero;
  }
  
  Condition TurboAssembler::CheckSmi(Operand src) {
    STATIC_ASSERT(kSmiTag == 0);
    testb(src, Immediate(kSmiTagMask));
    return zero;
  }
  
  void TurboAssembler::JumpIfSmi(Register src, Label* on_smi,
                                 Label::Distance near_jump) {
    Condition smi = CheckSmi(src);
    j(smi, on_smi, near_jump);
  }
  
  void MacroAssembler::JumpIfNotSmi(Register src, Label* on_not_smi,
                                    Label::Distance near_jump) {
    Condition smi = CheckSmi(src);
    j(NegateCondition(smi), on_not_smi, near_jump);
  }
  
  void MacroAssembler::JumpIfNotSmi(Operand src, Label* on_not_smi,
                                    Label::Distance near_jump) {
    Condition smi = CheckSmi(src);
    j(NegateCondition(smi), on_not_smi, near_jump);
  }
  
  void MacroAssembler::SmiAddConstant(Operand dst, Smi constant) {
    if (constant.value() != 0) {
      if (SmiValuesAre32Bits()) {
        addl(Operand(dst, kSmiShift / kBitsPerByte), Immediate(constant.value()));
      } else {
        DCHECK(SmiValuesAre31Bits());
        if (kTaggedSize == kInt64Size) {
          // Sign-extend value after addition
          movl(kScratchRegister, dst);
          addl(kScratchRegister, Immediate(constant));
          movsxlq(kScratchRegister, kScratchRegister);
          movq(dst, kScratchRegister);
        } else {
          DCHECK_EQ(kTaggedSize, kInt32Size);
          addl(dst, Immediate(constant));
        }
      }
    }
  }
  
  SmiIndex MacroAssembler::SmiToIndex(Register dst, Register src, int shift) {
    if (SmiValuesAre32Bits()) {
      DCHECK(is_uint6(shift));
      // There is a possible optimization if shift is in the range 60-63, but that
      // will (and must) never happen.
      if (dst != src) {
        movq(dst, src);
      }
      if (shift < kSmiShift) {
        sarq(dst, Immediate(kSmiShift - shift));
      } else {
        shlq(dst, Immediate(shift - kSmiShift));
      }
      return SmiIndex(dst, times_1);
    } else {
      DCHECK(SmiValuesAre31Bits());
      if (dst != src) {
        mov_tagged(dst, src);
      }
      // We have to sign extend the index register to 64-bit as the SMI might
      // be negative.
      movsxlq(dst, dst);
      if (shift < kSmiShift) {
        sarq(dst, Immediate(kSmiShift - shift));
      } else if (shift != kSmiShift) {
        if (shift - kSmiShift <= static_cast<int>(times_8)) {
          return SmiIndex(dst, static_cast<ScaleFactor>(shift - kSmiShift));
        }
        shlq(dst, Immediate(shift - kSmiShift));
      }
      return SmiIndex(dst, times_1);
    }
  }
  
  void TurboAssembler::Push(Smi source) {
    intptr_t smi = static_cast<intptr_t>(source.ptr());
    if (is_int32(smi)) {
      Push(Immediate(static_cast<int32_t>(smi)));
      return;
    }
    int first_byte_set = base::bits::CountTrailingZeros64(smi) / 8;
    int last_byte_set = (63 - base::bits::CountLeadingZeros64(smi)) / 8;
    if (first_byte_set == last_byte_set) {
      // This sequence has only 7 bytes, compared to the 12 bytes below.
      Push(Immediate(0));
      movb(Operand(rsp, first_byte_set),
           Immediate(static_cast<int8_t>(smi >> (8 * first_byte_set))));
      return;
    }
    Register constant = GetSmiConstant(source);
    Push(constant);
  }
  
  // ----------------------------------------------------------------------------
  
  void TurboAssembler::Move(Register dst, Register src) {
    if (dst != src) {
      movq(dst, src);
    }
  }
  
  void TurboAssembler::MovePair(Register dst0, Register src0, Register dst1,
                                Register src1) {
    if (dst0 != src1) {
      // Normal case: Writing to dst0 does not destroy src1.
      Move(dst0, src0);
      Move(dst1, src1);
    } else if (dst1 != src0) {
      // Only dst0 and src1 are the same register,
      // but writing to dst1 does not destroy src0.
      Move(dst1, src1);
      Move(dst0, src0);
    } else {
      // dst0 == src1, and dst1 == src0, a swap is required:
      // dst0 \/ src0
      // dst1 /\ src1
      xchgq(dst0, dst1);
    }
  }
  
  void TurboAssembler::MoveNumber(Register dst, double value) {
    int32_t smi;
    if (DoubleToSmiInteger(value, &smi)) {
      Move(dst, Smi::FromInt(smi));
    } else {
      movq_heap_number(dst, value);
    }
  }
  
  void TurboAssembler::Move(XMMRegister dst, uint32_t src) {
    if (src == 0) {
      Xorps(dst, dst);
    } else {
      unsigned nlz = base::bits::CountLeadingZeros(src);
      unsigned ntz = base::bits::CountTrailingZeros(src);
      unsigned pop = base::bits::CountPopulation(src);
      DCHECK_NE(0u, pop);
      if (pop + ntz + nlz == 32) {
        Pcmpeqd(dst, dst);
        if (ntz) Pslld(dst, static_cast<byte>(ntz + nlz));
        if (nlz) Psrld(dst, static_cast<byte>(nlz));
      } else {
        movl(kScratchRegister, Immediate(src));
        Movd(dst, kScratchRegister);
      }
    }
  }
  
  void TurboAssembler::Move(XMMRegister dst, uint64_t src) {
    if (src == 0) {
      Xorpd(dst, dst);
    } else {
      unsigned nlz = base::bits::CountLeadingZeros(src);
      unsigned ntz = base::bits::CountTrailingZeros(src);
      unsigned pop = base::bits::CountPopulation(src);
      DCHECK_NE(0u, pop);
      if (pop + ntz + nlz == 64) {
        Pcmpeqd(dst, dst);
        if (ntz) Psllq(dst, static_cast<byte>(ntz + nlz));
        if (nlz) Psrlq(dst, static_cast<byte>(nlz));
      } else {
        uint32_t lower = static_cast<uint32_t>(src);
        uint32_t upper = static_cast<uint32_t>(src >> 32);
        if (upper == 0) {
          Move(dst, lower);
        } else {
          movq(kScratchRegister, src);
          Movq(dst, kScratchRegister);
        }
      }
    }
  }
  
  // ----------------------------------------------------------------------------
  
  void MacroAssembler::Absps(XMMRegister dst) {
    Andps(dst, ExternalReferenceAsOperand(
                   ExternalReference::address_of_float_abs_constant()));
  }
  
  void MacroAssembler::Negps(XMMRegister dst) {
    Xorps(dst, ExternalReferenceAsOperand(
                   ExternalReference::address_of_float_neg_constant()));
  }
  
  void MacroAssembler::Abspd(XMMRegister dst) {
    Andps(dst, ExternalReferenceAsOperand(
                   ExternalReference::address_of_double_abs_constant()));
  }
  
  void MacroAssembler::Negpd(XMMRegister dst) {
    Xorps(dst, ExternalReferenceAsOperand(
                   ExternalReference::address_of_double_neg_constant()));
  }
  
  void MacroAssembler::Cmp(Register dst, Handle<Object> source) {
    AllowDeferredHandleDereference smi_check;
    if (source->IsSmi()) {
      Cmp(dst, Smi::cast(*source));
    } else {
      Move(kScratchRegister, Handle<HeapObject>::cast(source));
      cmp_tagged(dst, kScratchRegister);
    }
  }
  
  void MacroAssembler::Cmp(Operand dst, Handle<Object> source) {
    AllowDeferredHandleDereference smi_check;
    if (source->IsSmi()) {
      Cmp(dst, Smi::cast(*source));
    } else {
      Move(kScratchRegister, Handle<HeapObject>::cast(source));
      cmp_tagged(dst, kScratchRegister);
    }
  }
  
  void MacroAssembler::JumpIfIsInRange(Register value, unsigned lower_limit,
                                       unsigned higher_limit, Label* on_in_range,
                                       Label::Distance near_jump) {
    if (lower_limit != 0) {
      leal(kScratchRegister, Operand(value, 0u - lower_limit));
      cmpl(kScratchRegister, Immediate(higher_limit - lower_limit));
    } else {
      cmpl(value, Immediate(higher_limit));
    }
    j(below_equal, on_in_range, near_jump);
  }
  
  void TurboAssembler::Push(Handle<HeapObject> source) {
    Move(kScratchRegister, source);
    Push(kScratchRegister);
  }
  
  void TurboAssembler::Move(Register result, Handle<HeapObject> object,
                            RelocInfo::Mode rmode) {
    if (FLAG_embedded_builtins) {
      if (root_array_available_ && options().isolate_independent_code) {
        IndirectLoadConstant(result, object);
        return;
      }
    }
    if (RelocInfo::IsCompressedEmbeddedObject(rmode)) {
      EmbeddedObjectIndex index = AddEmbeddedObject(object);
      DCHECK(is_uint32(index));
      movl(result, Immediate(static_cast<int>(index), rmode));
    } else {
      DCHECK(RelocInfo::IsFullEmbeddedObject(rmode));
      movq(result, Immediate64(object.address(), rmode));
    }
  }
  
  void TurboAssembler::Move(Operand dst, Handle<HeapObject> object,
                            RelocInfo::Mode rmode) {
    Move(kScratchRegister, object, rmode);
    movq(dst, kScratchRegister);
  }
  
  void TurboAssembler::MoveStringConstant(Register result,
                                          const StringConstantBase* string,
                                          RelocInfo::Mode rmode) {
    movq_string(result, string);
  }
  
  void MacroAssembler::Drop(int stack_elements) {
    if (stack_elements > 0) {
      addq(rsp, Immediate(stack_elements * kSystemPointerSize));
    }
  }
  
  void MacroAssembler::DropUnderReturnAddress(int stack_elements,
                                              Register scratch) {
    DCHECK_GT(stack_elements, 0);
    if (stack_elements == 1) {
      popq(MemOperand(rsp, 0));
      return;
    }
  
    PopReturnAddressTo(scratch);
    Drop(stack_elements);
    PushReturnAddressFrom(scratch);
  }
  
  void TurboAssembler::Push(Register src) { pushq(src); }
  
  void TurboAssembler::Push(Operand src) { pushq(src); }
  
  void MacroAssembler::PushQuad(Operand src) { pushq(src); }
  
  void TurboAssembler::Push(Immediate value) { pushq(value); }
  
  void MacroAssembler::PushImm32(int32_t imm32) { pushq_imm32(imm32); }
  
  void MacroAssembler::Pop(Register dst) { popq(dst); }
  
  void MacroAssembler::Pop(Operand dst) { popq(dst); }
  
  void MacroAssembler::PopQuad(Operand dst) { popq(dst); }
  
  void TurboAssembler::Jump(ExternalReference ext) {
    LoadAddress(kScratchRegister, ext);
    jmp(kScratchRegister);
  }
  
  void TurboAssembler::Jump(Operand op) { jmp(op); }
  
  void TurboAssembler::Jump(Address destination, RelocInfo::Mode rmode) {
    Move(kScratchRegister, destination, rmode);
    jmp(kScratchRegister);
  }
  
  void TurboAssembler::Jump(Handle<Code> code_object, RelocInfo::Mode rmode,
                            Condition cc) {
    DCHECK_IMPLIES(options().isolate_independent_code,
                   Builtins::IsIsolateIndependentBuiltin(*code_object));
    if (options().inline_offheap_trampolines) {
      int builtin_index = Builtins::kNoBuiltinId;
      if (isolate()->builtins()->IsBuiltinHandle(code_object, &builtin_index) &&
          Builtins::IsIsolateIndependent(builtin_index)) {
        Label skip;
        if (cc != always) {
          if (cc == never) return;
          j(NegateCondition(cc), &skip, Label::kNear);
        }
        // Inline the trampoline.
        RecordCommentForOffHeapTrampoline(builtin_index);
        CHECK_NE(builtin_index, Builtins::kNoBuiltinId);
        EmbeddedData d = EmbeddedData::FromBlob();
        Address entry = d.InstructionStartOfBuiltin(builtin_index);
        Move(kScratchRegister, entry, RelocInfo::OFF_HEAP_TARGET);
        jmp(kScratchRegister);
        bind(&skip);
        return;
      }
    }
    j(cc, code_object, rmode);
  }
  
  void MacroAssembler::JumpToInstructionStream(Address entry) {
    Move(kOffHeapTrampolineRegister, entry, RelocInfo::OFF_HEAP_TARGET);
    jmp(kOffHeapTrampolineRegister);
  }
  
  void TurboAssembler::Call(ExternalReference ext) {
    LoadAddress(kScratchRegister, ext);
    call(kScratchRegister);
  }
  
  void TurboAssembler::Call(Operand op) {
    if (!CpuFeatures::IsSupported(ATOM)) {
      call(op);
    } else {
      movq(kScratchRegister, op);
      call(kScratchRegister);
    }
  }
  
  void TurboAssembler::Call(Address destination, RelocInfo::Mode rmode) {
    Move(kScratchRegister, destination, rmode);
    call(kScratchRegister);
  }
  
  void TurboAssembler::Call(Handle<Code> code_object, RelocInfo::Mode rmode) {
    DCHECK_IMPLIES(options().isolate_independent_code,
                   Builtins::IsIsolateIndependentBuiltin(*code_object));
    if (options().inline_offheap_trampolines) {
      int builtin_index = Builtins::kNoBuiltinId;
      if (isolate()->builtins()->IsBuiltinHandle(code_object, &builtin_index) &&
          Builtins::IsIsolateIndependent(builtin_index)) {
        // Inline the trampoline.
        RecordCommentForOffHeapTrampoline(builtin_index);
        CHECK_NE(builtin_index, Builtins::kNoBuiltinId);
        EmbeddedData d = EmbeddedData::FromBlob();
        Address entry = d.InstructionStartOfBuiltin(builtin_index);
        Move(kScratchRegister, entry, RelocInfo::OFF_HEAP_TARGET);
        call(kScratchRegister);
        return;
      }
    }
    DCHECK(RelocInfo::IsCodeTarget(rmode));
    call(code_object, rmode);
  }
  
  Operand TurboAssembler::EntryFromBuiltinIndexAsOperand(Register builtin_index) {
  #if defined(V8_COMPRESS_POINTERS) || defined(V8_31BIT_SMIS_ON_64BIT_ARCH)
    STATIC_ASSERT(kSmiShiftSize == 0);
    STATIC_ASSERT(kSmiTagSize == 1);
    STATIC_ASSERT(kSmiTag == 0);
  
    // The builtin_index register contains the builtin index as a Smi.
    // Untagging is folded into the indexing operand below (we use times_4 instead
    // of times_8 since smis are already shifted by one).
    return Operand(kRootRegister, builtin_index, times_4,
                   IsolateData::builtin_entry_table_offset());
  #else   // defined(V8_COMPRESS_POINTERS) || defined(V8_31BIT_SMIS_ON_64BIT_ARCH)
    STATIC_ASSERT(kSmiShiftSize == 31);
    STATIC_ASSERT(kSmiTagSize == 1);
    STATIC_ASSERT(kSmiTag == 0);
  
    // The builtin_index register contains the builtin index as a Smi.
    SmiUntag(builtin_index, builtin_index);
    return Operand(kRootRegister, builtin_index, times_8,
                   IsolateData::builtin_entry_table_offset());
  #endif  // defined(V8_COMPRESS_POINTERS) || defined(V8_31BIT_SMIS_ON_64BIT_ARCH)
  }
  
  void TurboAssembler::CallBuiltinByIndex(Register builtin_index) {
    Call(EntryFromBuiltinIndexAsOperand(builtin_index));
  }
  
  void TurboAssembler::LoadCodeObjectEntry(Register destination,
                                           Register code_object) {
    // Code objects are called differently depending on whether we are generating
    // builtin code (which will later be embedded into the binary) or compiling
    // user JS code at runtime.
    // * Builtin code runs in --jitless mode and thus must not call into on-heap
    //   Code targets. Instead, we dispatch through the builtins entry table.
    // * Codegen at runtime does not have this restriction and we can use the
    //   shorter, branchless instruction sequence. The assumption here is that
    //   targets are usually generated code and not builtin Code objects.
  
    if (options().isolate_independent_code) {
      DCHECK(root_array_available());
      Label if_code_is_off_heap, out;
  
      // Check whether the Code object is an off-heap trampoline. If so, call its
      // (off-heap) entry point directly without going through the (on-heap)
      // trampoline.  Otherwise, just call the Code object as always.
      testl(FieldOperand(code_object, Code::kFlagsOffset),
            Immediate(Code::IsOffHeapTrampoline::kMask));
      j(not_equal, &if_code_is_off_heap);
  
      // Not an off-heap trampoline, the entry point is at
      // Code::raw_instruction_start().
      Move(destination, code_object);
      addq(destination, Immediate(Code::kHeaderSize - kHeapObjectTag));
      jmp(&out);
  
      // An off-heap trampoline, the entry point is loaded from the builtin entry
      // table.
      bind(&if_code_is_off_heap);
      movl(destination, FieldOperand(code_object, Code::kBuiltinIndexOffset));
      movq(destination,
           Operand(kRootRegister, destination, times_system_pointer_size,
                   IsolateData::builtin_entry_table_offset()));
  
      bind(&out);
    } else {
      Move(destination, code_object);
      addq(destination, Immediate(Code::kHeaderSize - kHeapObjectTag));
    }
  }
  
  void TurboAssembler::CallCodeObject(Register code_object) {
    LoadCodeObjectEntry(code_object, code_object);
    call(code_object);
  }
  
  void TurboAssembler::JumpCodeObject(Register code_object) {
    LoadCodeObjectEntry(code_object, code_object);
    jmp(code_object);
  }
  
  void TurboAssembler::RetpolineCall(Register reg) {
    Label setup_return, setup_target, inner_indirect_branch, capture_spec;
  
    jmp(&setup_return);  // Jump past the entire retpoline below.
  
    bind(&inner_indirect_branch);
    call(&setup_target);
  
    bind(&capture_spec);
    pause();
    jmp(&capture_spec);
  
    bind(&setup_target);
    movq(Operand(rsp, 0), reg);
    ret(0);
  
    bind(&setup_return);
    call(&inner_indirect_branch);  // Callee will return after this instruction.
  }
  
  void TurboAssembler::RetpolineCall(Address destination, RelocInfo::Mode rmode) {
    Move(kScratchRegister, destination, rmode);
    RetpolineCall(kScratchRegister);
  }
  
  void TurboAssembler::RetpolineJump(Register reg) {
    Label setup_target, capture_spec;
  
    call(&setup_target);
  
    bind(&capture_spec);
    pause();
    jmp(&capture_spec);
  
    bind(&setup_target);
    movq(Operand(rsp, 0), reg);
    ret(0);
  }
  
  void TurboAssembler::Pextrd(Register dst, XMMRegister src, int8_t imm8) {
    if (imm8 == 0) {
      Movd(dst, src);
      return;
    }
    if (CpuFeatures::IsSupported(SSE4_1)) {
      CpuFeatureScope sse_scope(this, SSE4_1);
      pextrd(dst, src, imm8);
      return;
    }
    DCHECK_EQ(1, imm8);
    movq(dst, src);
    shrq(dst, Immediate(32));
  }
  
  void TurboAssembler::Pinsrd(XMMRegister dst, Register src, int8_t imm8) {
    if (CpuFeatures::IsSupported(SSE4_1)) {
      CpuFeatureScope sse_scope(this, SSE4_1);
      pinsrd(dst, src, imm8);
      return;
    }
    Movd(kScratchDoubleReg, src);
    if (imm8 == 1) {
      punpckldq(dst, kScratchDoubleReg);
    } else {
      DCHECK_EQ(0, imm8);
      Movss(dst, kScratchDoubleReg);
    }
  }
  
  void TurboAssembler::Pinsrd(XMMRegister dst, Operand src, int8_t imm8) {
    if (CpuFeatures::IsSupported(SSE4_1)) {
      CpuFeatureScope sse_scope(this, SSE4_1);
      pinsrd(dst, src, imm8);
      return;
    }
    Movd(kScratchDoubleReg, src);
    if (imm8 == 1) {
      punpckldq(dst, kScratchDoubleReg);
    } else {
      DCHECK_EQ(0, imm8);
      Movss(dst, kScratchDoubleReg);
    }
  }
  
  void TurboAssembler::Lzcntl(Register dst, Register src) {
    if (CpuFeatures::IsSupported(LZCNT)) {
      CpuFeatureScope scope(this, LZCNT);
      lzcntl(dst, src);
      return;
    }
    Label not_zero_src;
    bsrl(dst, src);
    j(not_zero, &not_zero_src, Label::kNear);
    Set(dst, 63);  // 63^31 == 32
    bind(&not_zero_src);
    xorl(dst, Immediate(31));  // for x in [0..31], 31^x == 31 - x
  }
  
  void TurboAssembler::Lzcntl(Register dst, Operand src) {
    if (CpuFeatures::IsSupported(LZCNT)) {
      CpuFeatureScope scope(this, LZCNT);
      lzcntl(dst, src);
      return;
    }
    Label not_zero_src;
    bsrl(dst, src);
    j(not_zero, &not_zero_src, Label::kNear);
    Set(dst, 63);  // 63^31 == 32
    bind(&not_zero_src);
    xorl(dst, Immediate(31));  // for x in [0..31], 31^x == 31 - x
  }
  
  void TurboAssembler::Lzcntq(Register dst, Register src) {
    if (CpuFeatures::IsSupported(LZCNT)) {
      CpuFeatureScope scope(this, LZCNT);
      lzcntq(dst, src);
      return;
    }
    Label not_zero_src;
    bsrq(dst, src);
    j(not_zero, &not_zero_src, Label::kNear);
    Set(dst, 127);  // 127^63 == 64
    bind(&not_zero_src);
    xorl(dst, Immediate(63));  // for x in [0..63], 63^x == 63 - x
  }
  
  void TurboAssembler::Lzcntq(Register dst, Operand src) {
    if (CpuFeatures::IsSupported(LZCNT)) {
      CpuFeatureScope scope(this, LZCNT);
      lzcntq(dst, src);
      return;
    }
    Label not_zero_src;
    bsrq(dst, src);
    j(not_zero, &not_zero_src, Label::kNear);
    Set(dst, 127);  // 127^63 == 64
    bind(&not_zero_src);
    xorl(dst, Immediate(63));  // for x in [0..63], 63^x == 63 - x
  }
  
  void TurboAssembler::Tzcntq(Register dst, Register src) {
    if (CpuFeatures::IsSupported(BMI1)) {
      CpuFeatureScope scope(this, BMI1);
      tzcntq(dst, src);
      return;
    }
    Label not_zero_src;
    bsfq(dst, src);
    j(not_zero, &not_zero_src, Label::kNear);
    // Define the result of tzcnt(0) separately, because bsf(0) is undefined.
    Set(dst, 64);
    bind(&not_zero_src);
  }
  
  void TurboAssembler::Tzcntq(Register dst, Operand src) {
    if (CpuFeatures::IsSupported(BMI1)) {
      CpuFeatureScope scope(this, BMI1);
      tzcntq(dst, src);
      return;
    }
    Label not_zero_src;
    bsfq(dst, src);
    j(not_zero, &not_zero_src, Label::kNear);
    // Define the result of tzcnt(0) separately, because bsf(0) is undefined.
    Set(dst, 64);
    bind(&not_zero_src);
  }
  
  void TurboAssembler::Tzcntl(Register dst, Register src) {
    if (CpuFeatures::IsSupported(BMI1)) {
      CpuFeatureScope scope(this, BMI1);
      tzcntl(dst, src);
      return;
    }
    Label not_zero_src;
    bsfl(dst, src);
    j(not_zero, &not_zero_src, Label::kNear);
    Set(dst, 32);  // The result of tzcnt is 32 if src = 0.
    bind(&not_zero_src);
  }
  
  void TurboAssembler::Tzcntl(Register dst, Operand src) {
    if (CpuFeatures::IsSupported(BMI1)) {
      CpuFeatureScope scope(this, BMI1);
      tzcntl(dst, src);
      return;
    }
    Label not_zero_src;
    bsfl(dst, src);
    j(not_zero, &not_zero_src, Label::kNear);
    Set(dst, 32);  // The result of tzcnt is 32 if src = 0.
    bind(&not_zero_src);
  }
  
  void TurboAssembler::Popcntl(Register dst, Register src) {
    if (CpuFeatures::IsSupported(POPCNT)) {
      CpuFeatureScope scope(this, POPCNT);
      popcntl(dst, src);
      return;
    }
    UNREACHABLE();
  }
  
  void TurboAssembler::Popcntl(Register dst, Operand src) {
    if (CpuFeatures::IsSupported(POPCNT)) {
      CpuFeatureScope scope(this, POPCNT);
      popcntl(dst, src);
      return;
    }
    UNREACHABLE();
  }
  
  void TurboAssembler::Popcntq(Register dst, Register src) {
    if (CpuFeatures::IsSupported(POPCNT)) {
      CpuFeatureScope scope(this, POPCNT);
      popcntq(dst, src);
      return;
    }
    UNREACHABLE();
  }
  
  void TurboAssembler::Popcntq(Register dst, Operand src) {
    if (CpuFeatures::IsSupported(POPCNT)) {
      CpuFeatureScope scope(this, POPCNT);
      popcntq(dst, src);
      return;
    }
    UNREACHABLE();
  }
  
  // Order general registers are pushed by Pushad:
  // rax, rcx, rdx, rbx, rsi, rdi, r8, r9, r11, r14, r15.
  const int
      MacroAssembler::kSafepointPushRegisterIndices[Register::kNumRegisters] = {
          0, 1, 2, 3, -1, -1, 4, 5, 6, 7, -1, 8, 9, -1, 10, 11};
  
  void MacroAssembler::PushStackHandler() {
    // Adjust this code if not the case.
    STATIC_ASSERT(StackHandlerConstants::kSize == 2 * kSystemPointerSize);
    STATIC_ASSERT(StackHandlerConstants::kNextOffset == 0);
  
    Push(Immediate(0));  // Padding.
  
    // Link the current handler as the next handler.
    ExternalReference handler_address =
        ExternalReference::Create(IsolateAddressId::kHandlerAddress, isolate());
    Push(ExternalReferenceAsOperand(handler_address));
  
    // Set this new handler as the current one.
    movq(ExternalReferenceAsOperand(handler_address), rsp);
  }
  
  void MacroAssembler::PopStackHandler() {
    STATIC_ASSERT(StackHandlerConstants::kNextOffset == 0);
    ExternalReference handler_address =
        ExternalReference::Create(IsolateAddressId::kHandlerAddress, isolate());
    Pop(ExternalReferenceAsOperand(handler_address));
    addq(rsp, Immediate(StackHandlerConstants::kSize - kSystemPointerSize));
  }
  
  void TurboAssembler::Ret() { ret(0); }
  
  void TurboAssembler::Ret(int bytes_dropped, Register scratch) {
    if (is_uint16(bytes_dropped)) {
      ret(bytes_dropped);
    } else {
      PopReturnAddressTo(scratch);
      addq(rsp, Immediate(bytes_dropped));
      PushReturnAddressFrom(scratch);
      ret(0);
    }
  }
  
  void MacroAssembler::CmpObjectType(Register heap_object, InstanceType type,
                                     Register map) {
    LoadTaggedPointerField(map,
                           FieldOperand(heap_object, HeapObject::kMapOffset));
    CmpInstanceType(map, type);
  }
  
  void MacroAssembler::CmpInstanceType(Register map, InstanceType type) {
    cmpw(FieldOperand(map, Map::kInstanceTypeOffset), Immediate(type));
  }
  
  void MacroAssembler::AssertNotSmi(Register object) {
    if (emit_debug_code()) {
      Condition is_smi = CheckSmi(object);
      Check(NegateCondition(is_smi), AbortReason::kOperandIsASmi);
    }
  }
  
  void MacroAssembler::AssertSmi(Register object) {
    if (emit_debug_code()) {
      Condition is_smi = CheckSmi(object);
      Check(is_smi, AbortReason::kOperandIsNotASmi);
    }
  }
  
  void MacroAssembler::AssertSmi(Operand object) {
    if (emit_debug_code()) {
      Condition is_smi = CheckSmi(object);
      Check(is_smi, AbortReason::kOperandIsNotASmi);
    }
  }
  
  void TurboAssembler::AssertZeroExtended(Register int32_register) {
    if (emit_debug_code()) {
      DCHECK_NE(int32_register, kScratchRegister);
      movq(kScratchRegister, int64_t{0x0000000100000000});
      cmpq(kScratchRegister, int32_register);
      Check(above_equal, AbortReason::k32BitValueInRegisterIsNotZeroExtended);
    }
  }
  
  void MacroAssembler::AssertConstructor(Register object) {
    if (emit_debug_code()) {
      testb(object, Immediate(kSmiTagMask));
      Check(not_equal, AbortReason::kOperandIsASmiAndNotAConstructor);
      Push(object);
      LoadTaggedPointerField(object,
                             FieldOperand(object, HeapObject::kMapOffset));
      testb(FieldOperand(object, Map::kBitFieldOffset),
            Immediate(Map::IsConstructorBit::kMask));
      Pop(object);
      Check(not_zero, AbortReason::kOperandIsNotAConstructor);
    }
  }
  
  void MacroAssembler::AssertFunction(Register object) {
    if (emit_debug_code()) {
      testb(object, Immediate(kSmiTagMask));
      Check(not_equal, AbortReason::kOperandIsASmiAndNotAFunction);
      Push(object);
      CmpObjectType(object, JS_FUNCTION_TYPE, object);
      Pop(object);
      Check(equal, AbortReason::kOperandIsNotAFunction);
    }
  }
  
  void MacroAssembler::AssertBoundFunction(Register object) {
    if (emit_debug_code()) {
      testb(object, Immediate(kSmiTagMask));
      Check(not_equal, AbortReason::kOperandIsASmiAndNotABoundFunction);
      Push(object);
      CmpObjectType(object, JS_BOUND_FUNCTION_TYPE, object);
      Pop(object);
      Check(equal, AbortReason::kOperandIsNotABoundFunction);
    }
  }
  
  void MacroAssembler::AssertGeneratorObject(Register object) {
    if (!emit_debug_code()) return;
    testb(object, Immediate(kSmiTagMask));
    Check(not_equal, AbortReason::kOperandIsASmiAndNotAGeneratorObject);
  
    // Load map
    Register map = object;
    Push(object);
    LoadTaggedPointerField(map, FieldOperand(object, HeapObject::kMapOffset));
  
    Label do_check;
    // Check if JSGeneratorObject
    CmpInstanceType(map, JS_GENERATOR_OBJECT_TYPE);
    j(equal, &do_check);
  
    // Check if JSAsyncFunctionObject
    CmpInstanceType(map, JS_ASYNC_FUNCTION_OBJECT_TYPE);
    j(equal, &do_check);
  
    // Check if JSAsyncGeneratorObject
    CmpInstanceType(map, JS_ASYNC_GENERATOR_OBJECT_TYPE);
  
    bind(&do_check);
    // Restore generator object to register and perform assertion
    Pop(object);
    Check(equal, AbortReason::kOperandIsNotAGeneratorObject);
  }
  
  void MacroAssembler::AssertUndefinedOrAllocationSite(Register object) {
    if (emit_debug_code()) {
      Label done_checking;
      AssertNotSmi(object);
      Cmp(object, isolate()->factory()->undefined_value());
      j(equal, &done_checking);
      Cmp(FieldOperand(object, 0), isolate()->factory()->allocation_site_map());
      Assert(equal, AbortReason::kExpectedUndefinedOrCell);
      bind(&done_checking);
    }
  }
  
  void MacroAssembler::LoadWeakValue(Register in_out, Label* target_if_cleared) {
    cmpl(in_out, Immediate(kClearedWeakHeapObjectLower32));
    j(equal, target_if_cleared);
  
    andq(in_out, Immediate(~static_cast<int32_t>(kWeakHeapObjectMask)));
  }
  
  void MacroAssembler::IncrementCounter(StatsCounter* counter, int value) {
    DCHECK_GT(value, 0);
    if (FLAG_native_code_counters && counter->Enabled()) {
      Operand counter_operand =
          ExternalReferenceAsOperand(ExternalReference::Create(counter));
      // This operation has to be exactly 32-bit wide in case the external
      // reference table redirects the counter to a uint32_t dummy_stats_counter_
      // field.
      if (value == 1) {
        incl(counter_operand);
      } else {
        addl(counter_operand, Immediate(value));
      }
    }
  }
  
  void MacroAssembler::DecrementCounter(StatsCounter* counter, int value) {
    DCHECK_GT(value, 0);
    if (FLAG_native_code_counters && counter->Enabled()) {
      Operand counter_operand =
          ExternalReferenceAsOperand(ExternalReference::Create(counter));
      // This operation has to be exactly 32-bit wide in case the external
      // reference table redirects the counter to a uint32_t dummy_stats_counter_
      // field.
      if (value == 1) {
        decl(counter_operand);
      } else {
        subl(counter_operand, Immediate(value));
      }
    }
  }
  
  void MacroAssembler::MaybeDropFrames() {
    // Check whether we need to drop frames to restart a function on the stack.
    ExternalReference restart_fp =
        ExternalReference::debug_restart_fp_address(isolate());
    Load(rbx, restart_fp);
    testq(rbx, rbx);
  
    Label dont_drop;
    j(zero, &dont_drop, Label::kNear);
    Jump(BUILTIN_CODE(isolate(), FrameDropperTrampoline), RelocInfo::CODE_TARGET);
  
    bind(&dont_drop);
  }
  
  void TurboAssembler::PrepareForTailCall(const ParameterCount& callee_args_count,
                                          Register caller_args_count_reg,
                                          Register scratch0, Register scratch1) {
  #if DEBUG
    if (callee_args_count.is_reg()) {
      DCHECK(!AreAliased(callee_args_count.reg(), caller_args_count_reg, scratch0,
                         scratch1));
    } else {
      DCHECK(!AreAliased(caller_args_count_reg, scratch0, scratch1));
    }
  #endif
  
    // Calculate the destination address where we will put the return address
    // after we drop current frame.
    Register new_sp_reg = scratch0;
    if (callee_args_count.is_reg()) {
      subq(caller_args_count_reg, callee_args_count.reg());
      leaq(new_sp_reg,
           Operand(rbp, caller_args_count_reg, times_system_pointer_size,
                   StandardFrameConstants::kCallerPCOffset));
    } else {
      leaq(new_sp_reg,
           Operand(rbp, caller_args_count_reg, times_system_pointer_size,
                   StandardFrameConstants::kCallerPCOffset -
                       callee_args_count.immediate() * kSystemPointerSize));
    }
  
    if (FLAG_debug_code) {
      cmpq(rsp, new_sp_reg);
      Check(below, AbortReason::kStackAccessBelowStackPointer);
    }
  
    // Copy return address from caller's frame to current frame's return address
    // to avoid its trashing and let the following loop copy it to the right
    // place.
    Register tmp_reg = scratch1;
    movq(tmp_reg, Operand(rbp, StandardFrameConstants::kCallerPCOffset));
    movq(Operand(rsp, 0), tmp_reg);
  
    // Restore caller's frame pointer now as it could be overwritten by
    // the copying loop.
    movq(rbp, Operand(rbp, StandardFrameConstants::kCallerFPOffset));
  
    // +2 here is to copy both receiver and return address.
    Register count_reg = caller_args_count_reg;
    if (callee_args_count.is_reg()) {
      leaq(count_reg, Operand(callee_args_count.reg(), 2));
    } else {
      movq(count_reg, Immediate(callee_args_count.immediate() + 2));
      // TODO(ishell): Unroll copying loop for small immediate values.
    }
  
    // Now copy callee arguments to the caller frame going backwards to avoid
    // callee arguments corruption (source and destination areas could overlap).
    Label loop, entry;
    jmp(&entry, Label::kNear);
    bind(&loop);
    decq(count_reg);
    movq(tmp_reg, Operand(rsp, count_reg, times_system_pointer_size, 0));
    movq(Operand(new_sp_reg, count_reg, times_system_pointer_size, 0), tmp_reg);
    bind(&entry);
    cmpq(count_reg, Immediate(0));
    j(not_equal, &loop, Label::kNear);
  
    // Leave current frame.
    movq(rsp, new_sp_reg);
  }
  
  void MacroAssembler::InvokeFunction(Register function, Register new_target,
                                      const ParameterCount& actual,
                                      InvokeFlag flag) {
    LoadTaggedPointerField(
        rbx, FieldOperand(function, JSFunction::kSharedFunctionInfoOffset));
    movzxwq(rbx,
            FieldOperand(rbx, SharedFunctionInfo::kFormalParameterCountOffset));
  
    ParameterCount expected(rbx);
    InvokeFunction(function, new_target, expected, actual, flag);
  }
  
  void MacroAssembler::InvokeFunction(Register function, Register new_target,
                                      const ParameterCount& expected,
                                      const ParameterCount& actual,
                                      InvokeFlag flag) {
    DCHECK(function == rdi);
    LoadTaggedPointerField(rsi,
                           FieldOperand(function, JSFunction::kContextOffset));
    InvokeFunctionCode(rdi, new_target, expected, actual, flag);
  }
  
  void MacroAssembler::InvokeFunctionCode(Register function, Register new_target,
                                          const ParameterCount& expected,
                                          const ParameterCount& actual,
                                          InvokeFlag flag) {
    // You can't call a function without a valid frame.
    DCHECK(flag == JUMP_FUNCTION || has_frame());
    DCHECK(function == rdi);
    DCHECK_IMPLIES(new_target.is_valid(), new_target == rdx);
  
    // On function call, call into the debugger if necessary.
    CheckDebugHook(function, new_target, expected, actual);
  
    // Clear the new.target register if not given.
    if (!new_target.is_valid()) {
      LoadRoot(rdx, RootIndex::kUndefinedValue);
    }
  
    Label done;
    bool definitely_mismatches = false;
    InvokePrologue(expected, actual, &done, &definitely_mismatches, flag,
                   Label::kNear);
    if (!definitely_mismatches) {
      // We call indirectly through the code field in the function to
      // allow recompilation to take effect without changing any of the
      // call sites.
      static_assert(kJavaScriptCallCodeStartRegister == rcx, "ABI mismatch");
      LoadTaggedPointerField(rcx,
                             FieldOperand(function, JSFunction::kCodeOffset));
      if (flag == CALL_FUNCTION) {
        CallCodeObject(rcx);
      } else {
        DCHECK(flag == JUMP_FUNCTION);
        JumpCodeObject(rcx);
      }
      bind(&done);
    }
  }
  
  void MacroAssembler::InvokePrologue(const ParameterCount& expected,
                                      const ParameterCount& actual, Label* done,
                                      bool* definitely_mismatches,
                                      InvokeFlag flag,
                                      Label::Distance near_jump) {
    bool definitely_matches = false;
    *definitely_mismatches = false;
    Label invoke;
    if (expected.is_immediate()) {
      DCHECK(actual.is_immediate());
      Set(rax, actual.immediate());
      if (expected.immediate() == actual.immediate()) {
        definitely_matches = true;
      } else {
        if (expected.immediate() ==
            SharedFunctionInfo::kDontAdaptArgumentsSentinel) {
          // Don't worry about adapting arguments for built-ins that
          // don't want that done. Skip adaption code by making it look
          // like we have a match between expected and actual number of
          // arguments.
          definitely_matches = true;
        } else {
          *definitely_mismatches = true;
          Set(rbx, expected.immediate());
        }
      }
    } else {
      if (actual.is_immediate()) {
        // Expected is in register, actual is immediate. This is the
        // case when we invoke function values without going through the
        // IC mechanism.
        Set(rax, actual.immediate());
        cmpq(expected.reg(), Immediate(actual.immediate()));
        j(equal, &invoke, Label::kNear);
        DCHECK(expected.reg() == rbx);
      } else if (expected.reg() != actual.reg()) {
        // Both expected and actual are in (different) registers. This
        // is the case when we invoke functions using call and apply.
        cmpq(expected.reg(), actual.reg());
        j(equal, &invoke, Label::kNear);
        DCHECK(actual.reg() == rax);
        DCHECK(expected.reg() == rbx);
      } else {
        definitely_matches = true;
        Move(rax, actual.reg());
      }
    }
  
    if (!definitely_matches) {
      Handle<Code> adaptor = BUILTIN_CODE(isolate(), ArgumentsAdaptorTrampoline);
      if (flag == CALL_FUNCTION) {
        Call(adaptor, RelocInfo::CODE_TARGET);
        if (!*definitely_mismatches) {
          jmp(done, near_jump);
        }
      } else {
        Jump(adaptor, RelocInfo::CODE_TARGET);
      }
      bind(&invoke);
    }
  }
  
  void MacroAssembler::CheckDebugHook(Register fun, Register new_target,
                                      const ParameterCount& expected,
                                      const ParameterCount& actual) {
    Label skip_hook;
    ExternalReference debug_hook_active =
        ExternalReference::debug_hook_on_function_call_address(isolate());
    Operand debug_hook_active_operand =
        ExternalReferenceAsOperand(debug_hook_active);
    cmpb(debug_hook_active_operand, Immediate(0));
    j(equal, &skip_hook);
  
    {
      FrameScope frame(this,
                       has_frame() ? StackFrame::NONE : StackFrame::INTERNAL);
      if (expected.is_reg()) {
        SmiTag(expected.reg(), expected.reg());
        Push(expected.reg());
      }
      if (actual.is_reg()) {
        SmiTag(actual.reg(), actual.reg());
        Push(actual.reg());
        SmiUntag(actual.reg(), actual.reg());
      }
      if (new_target.is_valid()) {
        Push(new_target);
      }
      Push(fun);
      Push(fun);
      Push(StackArgumentsAccessor(rbp, actual).GetReceiverOperand());
      CallRuntime(Runtime::kDebugOnFunctionCall);
      Pop(fun);
      if (new_target.is_valid()) {
        Pop(new_target);
      }
      if (actual.is_reg()) {
        Pop(actual.reg());
        SmiUntag(actual.reg(), actual.reg());
      }
      if (expected.is_reg()) {
        Pop(expected.reg());
        SmiUntag(expected.reg(), expected.reg());
      }
    }
    bind(&skip_hook);
  }
  
  void TurboAssembler::StubPrologue(StackFrame::Type type) {
    pushq(rbp);  // Caller's frame pointer.
    movq(rbp, rsp);
    Push(Immediate(StackFrame::TypeToMarker(type)));
  }
  
  void TurboAssembler::Prologue() {
    pushq(rbp);  // Caller's frame pointer.
    movq(rbp, rsp);
    Push(rsi);  // Callee's context.
    Push(rdi);  // Callee's JS function.
  }
  
  void TurboAssembler::EnterFrame(StackFrame::Type type) {
    pushq(rbp);
    movq(rbp, rsp);
    Push(Immediate(StackFrame::TypeToMarker(type)));
  }
  
  void TurboAssembler::LeaveFrame(StackFrame::Type type) {
    if (emit_debug_code()) {
      cmpq(Operand(rbp, CommonFrameConstants::kContextOrFrameTypeOffset),
           Immediate(StackFrame::TypeToMarker(type)));
      Check(equal, AbortReason::kStackFrameTypesMustMatch);
    }
    movq(rsp, rbp);
    popq(rbp);
  }
  
  #ifdef V8_OS_WIN
  void TurboAssembler::AllocateStackSpace(Register bytes_scratch) {
    // In windows, we cannot increment the stack size by more than one page
    // (minimum page size is 4KB) without accessing at least one byte on the
    // page. Check this:
    // https://msdn.microsoft.com/en-us/library/aa227153(v=vs.60).aspx.
    Label check_offset;
    Label touch_next_page;
    jmp(&check_offset);
    bind(&touch_next_page);
    subq(rsp, Immediate(kStackPageSize));
    // Just to touch the page, before we increment further.
    movb(Operand(rsp, 0), Immediate(0));
    subq(bytes_scratch, Immediate(kStackPageSize));
  
    bind(&check_offset);
    cmpq(bytes_scratch, Immediate(kStackPageSize));
    j(greater, &touch_next_page);
  
    subq(rsp, bytes_scratch);
  }
  
  void TurboAssembler::AllocateStackSpace(int bytes) {
    while (bytes > kStackPageSize) {
      subq(rsp, Immediate(kStackPageSize));
      movb(Operand(rsp, 0), Immediate(0));
      bytes -= kStackPageSize;
    }
    subq(rsp, Immediate(bytes));
  }
  #endif
  
  void MacroAssembler::EnterExitFramePrologue(bool save_rax,
                                              StackFrame::Type frame_type) {
    DCHECK(frame_type == StackFrame::EXIT ||
           frame_type == StackFrame::BUILTIN_EXIT);
  
    // Set up the frame structure on the stack.
    // All constants are relative to the frame pointer of the exit frame.
    DCHECK_EQ(kFPOnStackSize + kPCOnStackSize,
              ExitFrameConstants::kCallerSPDisplacement);
    DCHECK_EQ(kFPOnStackSize, ExitFrameConstants::kCallerPCOffset);
    DCHECK_EQ(0 * kSystemPointerSize, ExitFrameConstants::kCallerFPOffset);
    pushq(rbp);
    movq(rbp, rsp);
  
    // Reserve room for entry stack pointer.
    Push(Immediate(StackFrame::TypeToMarker(frame_type)));
    DCHECK_EQ(-2 * kSystemPointerSize, ExitFrameConstants::kSPOffset);
    Push(Immediate(0));  // Saved entry sp, patched before call.
  
    // Save the frame pointer and the context in top.
    if (save_rax) {
      movq(r14, rax);  // Backup rax in callee-save register.
    }
  
    Store(
        ExternalReference::Create(IsolateAddressId::kCEntryFPAddress, isolate()),
        rbp);
    Store(ExternalReference::Create(IsolateAddressId::kContextAddress, isolate()),
          rsi);
    Store(
        ExternalReference::Create(IsolateAddressId::kCFunctionAddress, isolate()),
        rbx);
  }
  
  void MacroAssembler::EnterExitFrameEpilogue(int arg_stack_space,
                                              bool save_doubles) {
  #ifdef _WIN64
    const int kShadowSpace = 4;
    arg_stack_space += kShadowSpace;
  #endif
    // Optionally save all XMM registers.
    if (save_doubles) {
      int space = XMMRegister::kNumRegisters * kDoubleSize +
                  arg_stack_space * kSystemPointerSize;
      AllocateStackSpace(space);
      int offset = -ExitFrameConstants::kFixedFrameSizeFromFp;
      const RegisterConfiguration* config = RegisterConfiguration::Default();
      for (int i = 0; i < config->num_allocatable_double_registers(); ++i) {
        DoubleRegister reg =
            DoubleRegister::from_code(config->GetAllocatableDoubleCode(i));
        Movsd(Operand(rbp, offset - ((i + 1) * kDoubleSize)), reg);
      }
    } else if (arg_stack_space > 0) {
      AllocateStackSpace(arg_stack_space * kSystemPointerSize);
    }
  
    // Get the required frame alignment for the OS.
    const int kFrameAlignment = base::OS::ActivationFrameAlignment();
    if (kFrameAlignment > 0) {
      DCHECK(base::bits::IsPowerOfTwo(kFrameAlignment));
      DCHECK(is_int8(kFrameAlignment));
      andq(rsp, Immediate(-kFrameAlignment));
    }
  
    // Patch the saved entry sp.
    movq(Operand(rbp, ExitFrameConstants::kSPOffset), rsp);
  }
  
  void MacroAssembler::EnterExitFrame(int arg_stack_space, bool save_doubles,
                                      StackFrame::Type frame_type) {
    EnterExitFramePrologue(true, frame_type);
  
    // Set up argv in callee-saved register r15. It is reused in LeaveExitFrame,
    // so it must be retained across the C-call.
    int offset = StandardFrameConstants::kCallerSPOffset - kSystemPointerSize;
    leaq(r15, Operand(rbp, r14, times_system_pointer_size, offset));
  
    EnterExitFrameEpilogue(arg_stack_space, save_doubles);
  }
  
  void MacroAssembler::EnterApiExitFrame(int arg_stack_space) {
    EnterExitFramePrologue(false, StackFrame::EXIT);
    EnterExitFrameEpilogue(arg_stack_space, false);
  }
  
  void MacroAssembler::LeaveExitFrame(bool save_doubles, bool pop_arguments) {
    // Registers:
    // r15 : argv
    if (save_doubles) {
      int offset = -ExitFrameConstants::kFixedFrameSizeFromFp;
      const RegisterConfiguration* config = RegisterConfiguration::Default();
      for (int i = 0; i < config->num_allocatable_double_registers(); ++i) {
        DoubleRegister reg =
            DoubleRegister::from_code(config->GetAllocatableDoubleCode(i));
        Movsd(reg, Operand(rbp, offset - ((i + 1) * kDoubleSize)));
      }
    }
  
    if (pop_arguments) {
      // Get the return address from the stack and restore the frame pointer.
      movq(rcx, Operand(rbp, kFPOnStackSize));
      movq(rbp, Operand(rbp, 0 * kSystemPointerSize));
  
      // Drop everything up to and including the arguments and the receiver
      // from the caller stack.
      leaq(rsp, Operand(r15, 1 * kSystemPointerSize));
  
      PushReturnAddressFrom(rcx);
    } else {
      // Otherwise just leave the exit frame.
      leave();
    }
  
    LeaveExitFrameEpilogue();
  }
  
  void MacroAssembler::LeaveApiExitFrame() {
    movq(rsp, rbp);
    popq(rbp);
  
    LeaveExitFrameEpilogue();
  }
  
  void MacroAssembler::LeaveExitFrameEpilogue() {
    // Restore current context from top and clear it in debug mode.
    ExternalReference context_address =
        ExternalReference::Create(IsolateAddressId::kContextAddress, isolate());
    Operand context_operand = ExternalReferenceAsOperand(context_address);
    movq(rsi, context_operand);
  #ifdef DEBUG
    movq(context_operand, Immediate(Context::kInvalidContext));
  #endif
  
    // Clear the top frame.
    ExternalReference c_entry_fp_address =
        ExternalReference::Create(IsolateAddressId::kCEntryFPAddress, isolate());
    Operand c_entry_fp_operand = ExternalReferenceAsOperand(c_entry_fp_address);
    movq(c_entry_fp_operand, Immediate(0));
  }
  
  #ifdef _WIN64
  static const int kRegisterPassedArguments = 4;
  #else
  static const int kRegisterPassedArguments = 6;
  #endif
  
  void MacroAssembler::LoadNativeContextSlot(int index, Register dst) {
    LoadTaggedPointerField(dst, NativeContextOperand());
    LoadTaggedPointerField(dst, ContextOperand(dst, index));
  }
  
  int TurboAssembler::ArgumentStackSlotsForCFunctionCall(int num_arguments) {
    // On Windows 64 stack slots are reserved by the caller for all arguments
    // including the ones passed in registers, and space is always allocated for
    // the four register arguments even if the function takes fewer than four
    // arguments.
    // On AMD64 ABI (Linux/Mac) the first six arguments are passed in registers
    // and the caller does not reserve stack slots for them.
    DCHECK_GE(num_arguments, 0);
  #ifdef _WIN64
    const int kMinimumStackSlots = kRegisterPassedArguments;
    if (num_arguments < kMinimumStackSlots) return kMinimumStackSlots;
    return num_arguments;
  #else
    if (num_arguments < kRegisterPassedArguments) return 0;
    return num_arguments - kRegisterPassedArguments;
  #endif
  }
  
  void TurboAssembler::PrepareCallCFunction(int num_arguments) {
    int frame_alignment = base::OS::ActivationFrameAlignment();
    DCHECK_NE(frame_alignment, 0);
    DCHECK_GE(num_arguments, 0);
  
    // Make stack end at alignment and allocate space for arguments and old rsp.
    movq(kScratchRegister, rsp);
    DCHECK(base::bits::IsPowerOfTwo(frame_alignment));
    int argument_slots_on_stack =
        ArgumentStackSlotsForCFunctionCall(num_arguments);
    AllocateStackSpace((argument_slots_on_stack + 1) * kSystemPointerSize);
    andq(rsp, Immediate(-frame_alignment));
    movq(Operand(rsp, argument_slots_on_stack * kSystemPointerSize),
         kScratchRegister);
  }
  
  void TurboAssembler::CallCFunction(ExternalReference function,
                                     int num_arguments) {
    LoadAddress(rax, function);
    CallCFunction(rax, num_arguments);
  }
  
  void TurboAssembler::CallCFunction(Register function, int num_arguments) {
    DCHECK_LE(num_arguments, kMaxCParameters);
    DCHECK(has_frame());
    // Check stack alignment.
    if (emit_debug_code()) {
      CheckStackAlignment();
    }
  
    // Save the frame pointer and PC so that the stack layout remains iterable,
    // even without an ExitFrame which normally exists between JS and C frames.
    if (isolate() != nullptr) {
      Label get_pc;
      DCHECK(!AreAliased(kScratchRegister, function));
      leaq(kScratchRegister, Operand(&get_pc, 0));
      bind(&get_pc);
      movq(ExternalReferenceAsOperand(
               ExternalReference::fast_c_call_caller_pc_address(isolate())),
           kScratchRegister);
      movq(ExternalReferenceAsOperand(
               ExternalReference::fast_c_call_caller_fp_address(isolate())),
           rbp);
    }
  
    call(function);
  
    if (isolate() != nullptr) {
      // We don't unset the PC; the FP is the source of truth.
      movq(ExternalReferenceAsOperand(
               ExternalReference::fast_c_call_caller_fp_address(isolate())),
           Immediate(0));
    }
  
    DCHECK_NE(base::OS::ActivationFrameAlignment(), 0);
    DCHECK_GE(num_arguments, 0);
    int argument_slots_on_stack =
        ArgumentStackSlotsForCFunctionCall(num_arguments);
    movq(rsp, Operand(rsp, argument_slots_on_stack * kSystemPointerSize));
  }
  
  void TurboAssembler::CheckPageFlag(Register object, Register scratch, int mask,
                                     Condition cc, Label* condition_met,
                                     Label::Distance condition_met_distance) {
    DCHECK(cc == zero || cc == not_zero);
    if (scratch == object) {
      andq(scratch, Immediate(~kPageAlignmentMask));
    } else {
      movq(scratch, Immediate(~kPageAlignmentMask));
      andq(scratch, object);
    }
    if (mask < (1 << kBitsPerByte)) {
      testb(Operand(scratch, MemoryChunk::kFlagsOffset),
            Immediate(static_cast<uint8_t>(mask)));
    } else {
      testl(Operand(scratch, MemoryChunk::kFlagsOffset), Immediate(mask));
    }
    j(cc, condition_met, condition_met_distance);
  }
  
  void TurboAssembler::ComputeCodeStartAddress(Register dst) {
    Label current;
    bind(&current);
    int pc = pc_offset();
    // Load effective address to get the address of the current instruction.
    leaq(dst, Operand(&current, -pc));
  }
  
  void TurboAssembler::ResetSpeculationPoisonRegister() {
    // TODO(tebbi): Perhaps, we want to put an lfence here.
    Set(kSpeculationPoisonRegister, -1);
  }
  
  void TurboAssembler::CallForDeoptimization(Address target, int deopt_id) {
    NoRootArrayScope no_root_array(this);
    // Save the deopt id in r13 (we don't need the roots array from now on).
    movq(r13, Immediate(deopt_id));
    call(target, RelocInfo::RUNTIME_ENTRY);
  }
  
  }  // namespace internal
  }  // namespace v8
  
  #endif  // V8_TARGET_ARCH_X64
  