Rename A64 port to ARM64 port

src/a64/regexp-macro-assembler-a64.cc

Index: src/a64/regexp-macro-assembler-a64.cc
diff --git a/src/a64/regexp-macro-assembler-a64.cc b/src/a64/regexp-macro-assembler-a64.cc
deleted file mode 100644
index 0b6ade8509f1510f0216182016f961a59c0c392f..0000000000000000000000000000000000000000
--- a/src/a64/regexp-macro-assembler-a64.cc
+++ /dev/null
@@ -1,1730 +0,0 @@
-// Copyright 2013 the V8 project authors. All rights reserved.
-// Redistribution and use in source and binary forms, with or without
-// modification, are permitted provided that the following conditions are
-// met:
-//
-//     * Redistributions of source code must retain the above copyright
-//       notice, this list of conditions and the following disclaimer.
-//     * Redistributions in binary form must reproduce the above
-//       copyright notice, this list of conditions and the following
-//       disclaimer in the documentation and/or other materials provided
-//       with the distribution.
-//     * Neither the name of Google Inc. nor the names of its
-//       contributors may be used to endorse or promote products derived
-//       from this software without specific prior written permission.
-//
-// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
-// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
-// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
-// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
-// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
-// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
-// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
-// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
-// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
-// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
-// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-
-#include "v8.h"
-
-#if V8_TARGET_ARCH_A64
-
-#include "cpu-profiler.h"
-#include "unicode.h"
-#include "log.h"
-#include "code-stubs.h"
-#include "regexp-stack.h"
-#include "macro-assembler.h"
-#include "regexp-macro-assembler.h"
-#include "a64/regexp-macro-assembler-a64.h"
-
-namespace v8 {
-namespace internal {
-
-#ifndef V8_INTERPRETED_REGEXP
-/*
- * This assembler uses the following register assignment convention:
- * - w19     : Used to temporarely store a value before a call to C code.
- *             See CheckNotBackReferenceIgnoreCase.
- * - x20     : Pointer to the current code object (Code*),
- *             it includes the heap object tag.
- * - w21     : Current position in input, as negative offset from
- *             the end of the string. Please notice that this is
- *             the byte offset, not the character offset!
- * - w22     : Currently loaded character. Must be loaded using
- *             LoadCurrentCharacter before using any of the dispatch methods.
- * - x23     : Points to tip of backtrack stack.
- * - w24     : Position of the first character minus one: non_position_value.
- *             Used to initialize capture registers.
- * - x25     : Address at the end of the input string: input_end.
- *             Points to byte after last character in input.
- * - x26     : Address at the start of the input string: input_start.
- * - w27     : Where to start in the input string.
- * - x28     : Output array pointer.
- * - x29/fp  : Frame pointer. Used to access arguments, local variables and
- *             RegExp registers.
- * - x16/x17 : IP registers, used by assembler. Very volatile.
- * - csp     : Points to tip of C stack.
- *
- * - x0-x7   : Used as a cache to store 32 bit capture registers. These
- *             registers need to be retained every time a call to C code
- *             is done.
- *
- * The remaining registers are free for computations.
- * Each call to a public method should retain this convention.
- *
- * The stack will have the following structure:
- *
- *  Location    Name               Description
- *              (as referred to in
- *              the code)
- *
- *  - fp[104]   isolate            Address of the current isolate.
- *  - fp[96]    return_address     Secondary link/return address
- *                                 used by an exit frame if this is a
- *                                 native call.
- *  ^^^ csp when called ^^^
- *  - fp[88]    lr                 Return from the RegExp code.
- *  - fp[80]    r29                Old frame pointer (CalleeSaved).
- *  - fp[0..72] r19-r28            Backup of CalleeSaved registers.
- *  - fp[-8]    direct_call        1 => Direct call from JavaScript code.
- *                                 0 => Call through the runtime system.
- *  - fp[-16]   stack_base         High end of the memory area to use as
- *                                 the backtracking stack.
- *  - fp[-24]   output_size        Output may fit multiple sets of matches.
- *  - fp[-32]   input              Handle containing the input string.
- *  - fp[-40]   success_counter
- *  ^^^^^^^^^^^^^ From here and downwards we store 32 bit values ^^^^^^^^^^^^^
- *  - fp[-44]   register N         Capture registers initialized with
- *  - fp[-48]   register N + 1     non_position_value.
- *              ...                The first kNumCachedRegisters (N) registers
- *              ...                are cached in x0 to x7.
- *              ...                Only positions must be stored in the first
- *  -           ...                num_saved_registers_ registers.
- *  -           ...
- *  -           register N + num_registers - 1
- *  ^^^^^^^^^ csp ^^^^^^^^^
- *
- * The first num_saved_registers_ registers are initialized to point to
- * "character -1" in the string (i.e., char_size() bytes before the first
- * character of the string). The remaining registers start out as garbage.
- *
- * The data up to the return address must be placed there by the calling
- * code and the remaining arguments are passed in registers, e.g. by calling the
- * code entry as cast to a function with the signature:
- * int (*match)(String* input,
- *              int start_offset,
- *              Address input_start,
- *              Address input_end,
- *              int* output,
- *              int output_size,
- *              Address stack_base,
- *              bool direct_call = false,
- *              Address secondary_return_address,  // Only used by native call.
- *              Isolate* isolate)
- * The call is performed by NativeRegExpMacroAssembler::Execute()
- * (in regexp-macro-assembler.cc) via the CALL_GENERATED_REGEXP_CODE macro
- * in a64/simulator-a64.h.
- * When calling as a non-direct call (i.e., from C++ code), the return address
- * area is overwritten with the LR register by the RegExp code. When doing a
- * direct call from generated code, the return address is placed there by
- * the calling code, as in a normal exit frame.
- */
-
-#define __ ACCESS_MASM(masm_)
-
-RegExpMacroAssemblerA64::RegExpMacroAssemblerA64(
-    Mode mode,
-    int registers_to_save,
-    Zone* zone)
-    : NativeRegExpMacroAssembler(zone),
-      masm_(new MacroAssembler(zone->isolate(), NULL, kRegExpCodeSize)),
-      mode_(mode),
-      num_registers_(registers_to_save),
-      num_saved_registers_(registers_to_save),
-      entry_label_(),
-      start_label_(),
-      success_label_(),
-      backtrack_label_(),
-      exit_label_() {
-  __ SetStackPointer(csp);
-  ASSERT_EQ(0, registers_to_save % 2);
-  // We can cache at most 16 W registers in x0-x7.
-  STATIC_ASSERT(kNumCachedRegisters <= 16);
-  STATIC_ASSERT((kNumCachedRegisters % 2) == 0);
-  __ B(&entry_label_);   // We'll write the entry code later.
-  __ Bind(&start_label_);  // And then continue from here.
-}
-
-
-RegExpMacroAssemblerA64::~RegExpMacroAssemblerA64() {
-  delete masm_;
-  // Unuse labels in case we throw away the assembler without calling GetCode.
-  entry_label_.Unuse();
-  start_label_.Unuse();
-  success_label_.Unuse();
-  backtrack_label_.Unuse();
-  exit_label_.Unuse();
-  check_preempt_label_.Unuse();
-  stack_overflow_label_.Unuse();
-}
-
-int RegExpMacroAssemblerA64::stack_limit_slack()  {
-  return RegExpStack::kStackLimitSlack;
-}
-
-
-void RegExpMacroAssemblerA64::AdvanceCurrentPosition(int by) {
-  if (by != 0) {
-    __ Add(current_input_offset(),
-           current_input_offset(), by * char_size());
-  }
-}
-
-
-void RegExpMacroAssemblerA64::AdvanceRegister(int reg, int by) {
-  ASSERT((reg >= 0) && (reg < num_registers_));
-  if (by != 0) {
-    Register to_advance;
-    RegisterState register_state = GetRegisterState(reg);
-    switch (register_state) {
-      case STACKED:
-        __ Ldr(w10, register_location(reg));
-        __ Add(w10, w10, by);
-        __ Str(w10, register_location(reg));
-        break;
-      case CACHED_LSW:
-        to_advance = GetCachedRegister(reg);
-        __ Add(to_advance, to_advance, by);
-        break;
-      case CACHED_MSW:
-        to_advance = GetCachedRegister(reg);
-        __ Add(to_advance, to_advance,
-               static_cast<int64_t>(by) << kWRegSizeInBits);
-        break;
-      default:
-        UNREACHABLE();
-        break;
-    }
-  }
-}
-
-
-void RegExpMacroAssemblerA64::Backtrack() {
-  CheckPreemption();
-  Pop(w10);
-  __ Add(x10, code_pointer(), Operand(w10, UXTW));
-  __ Br(x10);
-}
-
-
-void RegExpMacroAssemblerA64::Bind(Label* label) {
-  __ Bind(label);
-}
-
-
-void RegExpMacroAssemblerA64::CheckCharacter(uint32_t c, Label* on_equal) {
-  CompareAndBranchOrBacktrack(current_character(), c, eq, on_equal);
-}
-
-
-void RegExpMacroAssemblerA64::CheckCharacterGT(uc16 limit, Label* on_greater) {
-  CompareAndBranchOrBacktrack(current_character(), limit, hi, on_greater);
-}
-
-
-void RegExpMacroAssemblerA64::CheckAtStart(Label* on_at_start) {
-  Label not_at_start;
-  // Did we start the match at the start of the input string?
-  CompareAndBranchOrBacktrack(start_offset(), 0, ne, &not_at_start);
-  // If we did, are we still at the start of the input string?
-  __ Add(x10, input_end(), Operand(current_input_offset(), SXTW));
-  __ Cmp(x10, input_start());
-  BranchOrBacktrack(eq, on_at_start);
-  __ Bind(&not_at_start);
-}
-
-
-void RegExpMacroAssemblerA64::CheckNotAtStart(Label* on_not_at_start) {
-  // Did we start the match at the start of the input string?
-  CompareAndBranchOrBacktrack(start_offset(), 0, ne, on_not_at_start);
-  // If we did, are we still at the start of the input string?
-  __ Add(x10, input_end(), Operand(current_input_offset(), SXTW));
-  __ Cmp(x10, input_start());
-  BranchOrBacktrack(ne, on_not_at_start);
-}
-
-
-void RegExpMacroAssemblerA64::CheckCharacterLT(uc16 limit, Label* on_less) {
-  CompareAndBranchOrBacktrack(current_character(), limit, lo, on_less);
-}
-
-
-void RegExpMacroAssemblerA64::CheckCharacters(Vector<const uc16> str,
-                                              int cp_offset,
-                                              Label* on_failure,
-                                              bool check_end_of_string) {
-  // This method is only ever called from the cctests.
-
-  if (check_end_of_string) {
-    // Is last character of required match inside string.
-    CheckPosition(cp_offset + str.length() - 1, on_failure);
-  }
-
-  Register characters_address = x11;
-
-  __ Add(characters_address,
-         input_end(),
-         Operand(current_input_offset(), SXTW));
-  if (cp_offset != 0) {
-    __ Add(characters_address, characters_address, cp_offset * char_size());
-  }
-
-  for (int i = 0; i < str.length(); i++) {
-    if (mode_ == ASCII) {
-      __ Ldrb(w10, MemOperand(characters_address, 1, PostIndex));
-      ASSERT(str[i] <= String::kMaxOneByteCharCode);
-    } else {
-      __ Ldrh(w10, MemOperand(characters_address, 2, PostIndex));
-    }
-    CompareAndBranchOrBacktrack(w10, str[i], ne, on_failure);
-  }
-}
-
-
-void RegExpMacroAssemblerA64::CheckGreedyLoop(Label* on_equal) {
-  __ Ldr(w10, MemOperand(backtrack_stackpointer()));
-  __ Cmp(current_input_offset(), w10);
-  __ Cset(x11, eq);
-  __ Add(backtrack_stackpointer(),
-         backtrack_stackpointer(), Operand(x11, LSL, kWRegSizeLog2));
-  BranchOrBacktrack(eq, on_equal);
-}
-
-void RegExpMacroAssemblerA64::CheckNotBackReferenceIgnoreCase(
-    int start_reg,
-    Label* on_no_match) {
-  Label fallthrough;
-
-  Register capture_start_offset = w10;
-  // Save the capture length in a callee-saved register so it will
-  // be preserved if we call a C helper.
-  Register capture_length = w19;
-  ASSERT(kCalleeSaved.IncludesAliasOf(capture_length));
-
-  // Find length of back-referenced capture.
-  ASSERT((start_reg % 2) == 0);
-  if (start_reg < kNumCachedRegisters) {
-    __ Mov(capture_start_offset.X(), GetCachedRegister(start_reg));
-    __ Lsr(x11, GetCachedRegister(start_reg), kWRegSizeInBits);
-  } else {
-    __ Ldp(w11, capture_start_offset, capture_location(start_reg, x10));
-  }
-  __ Sub(capture_length, w11, capture_start_offset);  // Length to check.
-  // Succeed on empty capture (including no capture).
-  __ Cbz(capture_length, &fallthrough);
-
-  // Check that there are enough characters left in the input.
-  __ Cmn(capture_length, current_input_offset());
-  BranchOrBacktrack(gt, on_no_match);
-
-  if (mode_ == ASCII) {
-    Label success;
-    Label fail;
-    Label loop_check;
-
-    Register capture_start_address = x12;
-    Register capture_end_addresss = x13;
-    Register current_position_address = x14;
-
-    __ Add(capture_start_address,
-           input_end(),
-           Operand(capture_start_offset, SXTW));
-    __ Add(capture_end_addresss,
-           capture_start_address,
-           Operand(capture_length, SXTW));
-    __ Add(current_position_address,
-           input_end(),
-           Operand(current_input_offset(), SXTW));
-
-    Label loop;
-    __ Bind(&loop);
-    __ Ldrb(w10, MemOperand(capture_start_address, 1, PostIndex));
-    __ Ldrb(w11, MemOperand(current_position_address, 1, PostIndex));
-    __ Cmp(w10, w11);
-    __ B(eq, &loop_check);
-
-    // Mismatch, try case-insensitive match (converting letters to lower-case).
-    __ Orr(w10, w10, 0x20);  // Convert capture character to lower-case.
-    __ Orr(w11, w11, 0x20);  // Also convert input character.
-    __ Cmp(w11, w10);
-    __ B(ne, &fail);
-    __ Sub(w10, w10, 'a');
-    __ Cmp(w10, 'z' - 'a');  // Is w10 a lowercase letter?
-    __ B(ls, &loop_check);  // In range 'a'-'z'.
-    // Latin-1: Check for values in range [224,254] but not 247.
-    __ Sub(w10, w10, 224 - 'a');
-    __ Cmp(w10, 254 - 224);
-    __ Ccmp(w10, 247 - 224, ZFlag, ls);  // Check for 247.
-    __ B(eq, &fail);  // Weren't Latin-1 letters.
-
-    __ Bind(&loop_check);
-    __ Cmp(capture_start_address, capture_end_addresss);
-    __ B(lt, &loop);
-    __ B(&success);
-
-    __ Bind(&fail);
-    BranchOrBacktrack(al, on_no_match);
-
-    __ Bind(&success);
-    // Compute new value of character position after the matched part.
-    __ Sub(current_input_offset().X(), current_position_address, input_end());
-    if (masm_->emit_debug_code()) {
-      __ Cmp(current_input_offset().X(), Operand(current_input_offset(), SXTW));
-      __ Ccmp(current_input_offset(), 0, NoFlag, eq);
-      // The current input offset should be <= 0, and fit in a W register.
-      __ Check(le, kOffsetOutOfRange);
-    }
-  } else {
-    ASSERT(mode_ == UC16);
-    int argument_count = 4;
-
-    // The cached registers need to be retained.
-    CPURegList cached_registers(CPURegister::kRegister, kXRegSizeInBits, 0, 7);
-    ASSERT((cached_registers.Count() * 2) == kNumCachedRegisters);
-    __ PushCPURegList(cached_registers);
-
-    // Put arguments into arguments registers.
-    // Parameters are
-    //   x0: Address byte_offset1 - Address captured substring's start.
-    //   x1: Address byte_offset2 - Address of current character position.
-    //   w2: size_t byte_length - length of capture in bytes(!)
-    //   x3: Isolate* isolate
-
-    // Address of start of capture.
-    __ Add(x0, input_end(), Operand(capture_start_offset, SXTW));
-    // Length of capture.
-    __ Mov(w2, capture_length);
-    // Address of current input position.
-    __ Add(x1, input_end(), Operand(current_input_offset(), SXTW));
-    // Isolate.
-    __ Mov(x3, ExternalReference::isolate_address(isolate()));
-
-    {
-      AllowExternalCallThatCantCauseGC scope(masm_);
-      ExternalReference function =
-          ExternalReference::re_case_insensitive_compare_uc16(isolate());
-      __ CallCFunction(function, argument_count);
-    }
-
-    // Check if function returned non-zero for success or zero for failure.
-    CompareAndBranchOrBacktrack(x0, 0, eq, on_no_match);
-    // On success, increment position by length of capture.
-    __ Add(current_input_offset(), current_input_offset(), capture_length);
-    // Reset the cached registers.
-    __ PopCPURegList(cached_registers);
-  }
-
-  __ Bind(&fallthrough);
-}
-
-void RegExpMacroAssemblerA64::CheckNotBackReference(
-    int start_reg,
-    Label* on_no_match) {
-  Label fallthrough;
-
-  Register capture_start_address = x12;
-  Register capture_end_address = x13;
-  Register current_position_address = x14;
-  Register capture_length = w15;
-
-  // Find length of back-referenced capture.
-  ASSERT((start_reg % 2) == 0);
-  if (start_reg < kNumCachedRegisters) {
-    __ Mov(x10, GetCachedRegister(start_reg));
-    __ Lsr(x11, GetCachedRegister(start_reg), kWRegSizeInBits);
-  } else {
-    __ Ldp(w11, w10, capture_location(start_reg, x10));
-  }
-  __ Sub(capture_length, w11, w10);  // Length to check.
-  // Succeed on empty capture (including no capture).
-  __ Cbz(capture_length, &fallthrough);
-
-  // Check that there are enough characters left in the input.
-  __ Cmn(capture_length, current_input_offset());
-  BranchOrBacktrack(gt, on_no_match);
-
-  // Compute pointers to match string and capture string
-  __ Add(capture_start_address, input_end(), Operand(w10, SXTW));
-  __ Add(capture_end_address,
-         capture_start_address,
-         Operand(capture_length, SXTW));
-  __ Add(current_position_address,
-         input_end(),
-         Operand(current_input_offset(), SXTW));
-
-  Label loop;
-  __ Bind(&loop);
-  if (mode_ == ASCII) {
-    __ Ldrb(w10, MemOperand(capture_start_address, 1, PostIndex));
-    __ Ldrb(w11, MemOperand(current_position_address, 1, PostIndex));
-  } else {
-    ASSERT(mode_ == UC16);
-    __ Ldrh(w10, MemOperand(capture_start_address, 2, PostIndex));
-    __ Ldrh(w11, MemOperand(current_position_address, 2, PostIndex));
-  }
-  __ Cmp(w10, w11);
-  BranchOrBacktrack(ne, on_no_match);
-  __ Cmp(capture_start_address, capture_end_address);
-  __ B(lt, &loop);
-
-  // Move current character position to position after match.
-  __ Sub(current_input_offset().X(), current_position_address, input_end());
-  if (masm_->emit_debug_code()) {
-    __ Cmp(current_input_offset().X(), Operand(current_input_offset(), SXTW));
-    __ Ccmp(current_input_offset(), 0, NoFlag, eq);
-    // The current input offset should be <= 0, and fit in a W register.
-    __ Check(le, kOffsetOutOfRange);
-  }
-  __ Bind(&fallthrough);
-}
-
-
-void RegExpMacroAssemblerA64::CheckNotCharacter(unsigned c,
-                                                Label* on_not_equal) {
-  CompareAndBranchOrBacktrack(current_character(), c, ne, on_not_equal);
-}
-
-
-void RegExpMacroAssemblerA64::CheckCharacterAfterAnd(uint32_t c,
-                                                     uint32_t mask,
-                                                     Label* on_equal) {
-  __ And(w10, current_character(), mask);
-  CompareAndBranchOrBacktrack(w10, c, eq, on_equal);
-}
-
-
-void RegExpMacroAssemblerA64::CheckNotCharacterAfterAnd(unsigned c,
-                                                        unsigned mask,
-                                                        Label* on_not_equal) {
-  __ And(w10, current_character(), mask);
-  CompareAndBranchOrBacktrack(w10, c, ne, on_not_equal);
-}
-
-
-void RegExpMacroAssemblerA64::CheckNotCharacterAfterMinusAnd(
-    uc16 c,
-    uc16 minus,
-    uc16 mask,
-    Label* on_not_equal) {
-  ASSERT(minus < String::kMaxUtf16CodeUnit);
-  __ Sub(w10, current_character(), minus);
-  __ And(w10, w10, mask);
-  CompareAndBranchOrBacktrack(w10, c, ne, on_not_equal);
-}
-
-
-void RegExpMacroAssemblerA64::CheckCharacterInRange(
-    uc16 from,
-    uc16 to,
-    Label* on_in_range) {
-  __ Sub(w10, current_character(), from);
-  // Unsigned lower-or-same condition.
-  CompareAndBranchOrBacktrack(w10, to - from, ls, on_in_range);
-}
-
-
-void RegExpMacroAssemblerA64::CheckCharacterNotInRange(
-    uc16 from,
-    uc16 to,
-    Label* on_not_in_range) {
-  __ Sub(w10, current_character(), from);
-  // Unsigned higher condition.
-  CompareAndBranchOrBacktrack(w10, to - from, hi, on_not_in_range);
-}
-
-
-void RegExpMacroAssemblerA64::CheckBitInTable(
-    Handle<ByteArray> table,
-    Label* on_bit_set) {
-  __ Mov(x11, Operand(table));
-  if ((mode_ != ASCII) || (kTableMask != String::kMaxOneByteCharCode)) {
-    __ And(w10, current_character(), kTableMask);
-    __ Add(w10, w10, ByteArray::kHeaderSize - kHeapObjectTag);
-  } else {
-    __ Add(w10, current_character(), ByteArray::kHeaderSize - kHeapObjectTag);
-  }
-  __ Ldrb(w11, MemOperand(x11, w10, UXTW));
-  CompareAndBranchOrBacktrack(w11, 0, ne, on_bit_set);
-}
-
-
-bool RegExpMacroAssemblerA64::CheckSpecialCharacterClass(uc16 type,
-                                                         Label* on_no_match) {
-  // Range checks (c in min..max) are generally implemented by an unsigned
-  // (c - min) <= (max - min) check
-  switch (type) {
-  case 's':
-    // Match space-characters
-    if (mode_ == ASCII) {
-      // One byte space characters are '\t'..'\r', ' ' and \u00a0.
-      Label success;
-      // Check for ' ' or 0x00a0.
-      __ Cmp(current_character(), ' ');
-      __ Ccmp(current_character(), 0x00a0, ZFlag, ne);
-      __ B(eq, &success);
-      // Check range 0x09..0x0d.
-      __ Sub(w10, current_character(), '\t');
-      CompareAndBranchOrBacktrack(w10, '\r' - '\t', hi, on_no_match);
-      __ Bind(&success);
-      return true;
-    }
-    return false;
-  case 'S':
-    // The emitted code for generic character classes is good enough.
-    return false;
-  case 'd':
-    // Match ASCII digits ('0'..'9').
-    __ Sub(w10, current_character(), '0');
-    CompareAndBranchOrBacktrack(w10, '9' - '0', hi, on_no_match);
-    return true;
-  case 'D':
-    // Match ASCII non-digits.
-    __ Sub(w10, current_character(), '0');
-    CompareAndBranchOrBacktrack(w10, '9' - '0', ls, on_no_match);
-    return true;
-  case '.': {
-    // Match non-newlines (not 0x0a('\n'), 0x0d('\r'), 0x2028 and 0x2029)
-    // Here we emit the conditional branch only once at the end to make branch
-    // prediction more efficient, even though we could branch out of here
-    // as soon as a character matches.
-    __ Cmp(current_character(), 0x0a);
-    __ Ccmp(current_character(), 0x0d, ZFlag, ne);
-    if (mode_ == UC16) {
-      __ Sub(w10, current_character(), 0x2028);
-      // If the Z flag was set we clear the flags to force a branch.
-      __ Ccmp(w10, 0x2029 - 0x2028, NoFlag, ne);
-      // ls -> !((C==1) && (Z==0))
-      BranchOrBacktrack(ls, on_no_match);
-    } else {
-      BranchOrBacktrack(eq, on_no_match);
-    }
-    return true;
-  }
-  case 'n': {
-    // Match newlines (0x0a('\n'), 0x0d('\r'), 0x2028 and 0x2029)
-    // We have to check all 4 newline characters before emitting
-    // the conditional branch.
-    __ Cmp(current_character(), 0x0a);
-    __ Ccmp(current_character(), 0x0d, ZFlag, ne);
-    if (mode_ == UC16) {
-      __ Sub(w10, current_character(), 0x2028);
-      // If the Z flag was set we clear the flags to force a fall-through.
-      __ Ccmp(w10, 0x2029 - 0x2028, NoFlag, ne);
-      // hi -> (C==1) && (Z==0)
-      BranchOrBacktrack(hi, on_no_match);
-    } else {
-      BranchOrBacktrack(ne, on_no_match);
-    }
-    return true;
-  }
-  case 'w': {
-    if (mode_ != ASCII) {
-      // Table is 128 entries, so all ASCII characters can be tested.
-      CompareAndBranchOrBacktrack(current_character(), 'z', hi, on_no_match);
-    }
-    ExternalReference map = ExternalReference::re_word_character_map();
-    __ Mov(x10, map);
-    __ Ldrb(w10, MemOperand(x10, current_character(), UXTW));
-    CompareAndBranchOrBacktrack(w10, 0, eq, on_no_match);
-    return true;
-  }
-  case 'W': {
-    Label done;
-    if (mode_ != ASCII) {
-      // Table is 128 entries, so all ASCII characters can be tested.
-      __ Cmp(current_character(), 'z');
-      __ B(hi, &done);
-    }
-    ExternalReference map = ExternalReference::re_word_character_map();
-    __ Mov(x10, map);
-    __ Ldrb(w10, MemOperand(x10, current_character(), UXTW));
-    CompareAndBranchOrBacktrack(w10, 0, ne, on_no_match);
-    __ Bind(&done);
-    return true;
-  }
-  case '*':
-    // Match any character.
-    return true;
-  // No custom implementation (yet): s(UC16), S(UC16).
-  default:
-    return false;
-  }
-}
-
-
-void RegExpMacroAssemblerA64::Fail() {
-  __ Mov(w0, FAILURE);
-  __ B(&exit_label_);
-}
-
-
-Handle<HeapObject> RegExpMacroAssemblerA64::GetCode(Handle<String> source) {
-  Label return_w0;
-  // Finalize code - write the entry point code now we know how many
-  // registers we need.
-
-  // Entry code:
-  __ Bind(&entry_label_);
-
-  // Arguments on entry:
-  // x0:  String*  input
-  // x1:  int      start_offset
-  // x2:  byte*    input_start
-  // x3:  byte*    input_end
-  // x4:  int*     output array
-  // x5:  int      output array size
-  // x6:  Address  stack_base
-  // x7:  int      direct_call
-
-  // The stack pointer should be csp on entry.
-  //  csp[8]:  address of the current isolate
-  //  csp[0]:  secondary link/return address used by native call
-
-  // Tell the system that we have a stack frame.  Because the type is MANUAL, no
-  // code is generated.
-  FrameScope scope(masm_, StackFrame::MANUAL);
-
-  // Push registers on the stack, only push the argument registers that we need.
-  CPURegList argument_registers(x0, x5, x6, x7);
-
-  CPURegList registers_to_retain = kCalleeSaved;
-  ASSERT(kCalleeSaved.Count() == 11);
-  registers_to_retain.Combine(lr);
-
-  ASSERT(csp.Is(__ StackPointer()));
-  __ PushCPURegList(registers_to_retain);
-  __ PushCPURegList(argument_registers);
-
-  // Set frame pointer in place.
-  __ Add(frame_pointer(), csp, argument_registers.Count() * kPointerSize);
-
-  // Initialize callee-saved registers.
-  __ Mov(start_offset(), w1);
-  __ Mov(input_start(), x2);
-  __ Mov(input_end(), x3);
-  __ Mov(output_array(), x4);
-
-  // Set the number of registers we will need to allocate, that is:
-  //   - success_counter (X register)
-  //   - (num_registers_ - kNumCachedRegisters) (W registers)
-  int num_wreg_to_allocate = num_registers_ - kNumCachedRegisters;
-  // Do not allocate registers on the stack if they can all be cached.
-  if (num_wreg_to_allocate < 0) { num_wreg_to_allocate = 0; }
-  // Make room for the success_counter.
-  num_wreg_to_allocate += 2;
-
-  // Make sure the stack alignment will be respected.
-  int alignment = masm_->ActivationFrameAlignment();
-  ASSERT_EQ(alignment % 16, 0);
-  int align_mask = (alignment / kWRegSize) - 1;
-  num_wreg_to_allocate = (num_wreg_to_allocate + align_mask) & ~align_mask;
-
-  // Check if we have space on the stack.
-  Label stack_limit_hit;
-  Label stack_ok;
-
-  ExternalReference stack_limit =
-      ExternalReference::address_of_stack_limit(isolate());
-  __ Mov(x10, stack_limit);
-  __ Ldr(x10, MemOperand(x10));
-  __ Subs(x10, csp, x10);
-
-  // Handle it if the stack pointer is already below the stack limit.
-  __ B(ls, &stack_limit_hit);
-
-  // Check if there is room for the variable number of registers above
-  // the stack limit.
-  __ Cmp(x10, num_wreg_to_allocate * kWRegSize);
-  __ B(hs, &stack_ok);
-
-  // Exit with OutOfMemory exception. There is not enough space on the stack
-  // for our working registers.
-  __ Mov(w0, EXCEPTION);
-  __ B(&return_w0);
-
-  __ Bind(&stack_limit_hit);
-  CallCheckStackGuardState(x10);
-  // If returned value is non-zero, we exit with the returned value as result.
-  __ Cbnz(w0, &return_w0);
-
-  __ Bind(&stack_ok);
-
-  // Allocate space on stack.
-  __ Claim(num_wreg_to_allocate, kWRegSize);
-
-  // Initialize success_counter with 0.
-  __ Str(wzr, MemOperand(frame_pointer(), kSuccessCounter));
-
-  // Find negative length (offset of start relative to end).
-  __ Sub(x10, input_start(), input_end());
-  if (masm_->emit_debug_code()) {
-    // Check that the input string length is < 2^30.
-    __ Neg(x11, x10);
-    __ Cmp(x11, (1<<30) - 1);
-    __ Check(ls, kInputStringTooLong);
-  }
-  __ Mov(current_input_offset(), w10);
-
-  // The non-position value is used as a clearing value for the
-  // capture registers, it corresponds to the position of the first character
-  // minus one.
-  __ Sub(non_position_value(), current_input_offset(), char_size());
-  __ Sub(non_position_value(), non_position_value(),
-         Operand(start_offset(), LSL, (mode_ == UC16) ? 1 : 0));
-  // We can store this value twice in an X register for initializing
-  // on-stack registers later.
-  __ Orr(twice_non_position_value(),
-         non_position_value().X(),
-         Operand(non_position_value().X(), LSL, kWRegSizeInBits));
-
-  // Initialize code pointer register.
-  __ Mov(code_pointer(), Operand(masm_->CodeObject()));
-
-  Label load_char_start_regexp, start_regexp;
-  // Load newline if index is at start, previous character otherwise.
-  __ Cbnz(start_offset(), &load_char_start_regexp);
-  __ Mov(current_character(), '\n');
-  __ B(&start_regexp);
-
-  // Global regexp restarts matching here.
-  __ Bind(&load_char_start_regexp);
-  // Load previous char as initial value of current character register.
-  LoadCurrentCharacterUnchecked(-1, 1);
-  __ Bind(&start_regexp);
-  // Initialize on-stack registers.
-  if (num_saved_registers_ > 0) {
-    ClearRegisters(0, num_saved_registers_ - 1);
-  }
-
-  // Initialize backtrack stack pointer.
-  __ Ldr(backtrack_stackpointer(), MemOperand(frame_pointer(), kStackBase));
-
-  // Execute
-  __ B(&start_label_);
-
-  if (backtrack_label_.is_linked()) {
-    __ Bind(&backtrack_label_);
-    Backtrack();
-  }
-
-  if (success_label_.is_linked()) {
-    Register first_capture_start = w15;
-
-    // Save captures when successful.
-    __ Bind(&success_label_);
-
-    if (num_saved_registers_ > 0) {
-      // V8 expects the output to be an int32_t array.
-      Register capture_start = w12;
-      Register capture_end = w13;
-      Register input_length = w14;
-
-      // Copy captures to output.
-
-      // Get string length.
-      __ Sub(x10, input_end(), input_start());
-      if (masm_->emit_debug_code()) {
-        // Check that the input string length is < 2^30.
-        __ Cmp(x10, (1<<30) - 1);
-        __ Check(ls, kInputStringTooLong);
-      }
-      // input_start has a start_offset offset on entry. We need to include
-      // it when computing the length of the whole string.
-      if (mode_ == UC16) {
-        __ Add(input_length, start_offset(), Operand(w10, LSR, 1));
-      } else {
-        __ Add(input_length, start_offset(), w10);
-      }
-
-      // Copy the results to the output array from the cached registers first.
-      for (int i = 0;
-           (i < num_saved_registers_) && (i < kNumCachedRegisters);
-           i += 2) {
-        __ Mov(capture_start.X(), GetCachedRegister(i));
-        __ Lsr(capture_end.X(), capture_start.X(), kWRegSizeInBits);
-        if ((i == 0) && global_with_zero_length_check()) {
-          // Keep capture start for the zero-length check later.
-          __ Mov(first_capture_start, capture_start);
-        }
-        // Offsets need to be relative to the start of the string.
-        if (mode_ == UC16) {
-          __ Add(capture_start, input_length, Operand(capture_start, ASR, 1));
-          __ Add(capture_end, input_length, Operand(capture_end, ASR, 1));
-        } else {
-          __ Add(capture_start, input_length, capture_start);
-          __ Add(capture_end, input_length, capture_end);
-        }
-        // The output pointer advances for a possible global match.
-        __ Stp(capture_start,
-               capture_end,
-               MemOperand(output_array(), kPointerSize, PostIndex));
-      }
-
-      // Only carry on if there are more than kNumCachedRegisters capture
-      // registers.
-      int num_registers_left_on_stack =
-          num_saved_registers_ - kNumCachedRegisters;
-      if (num_registers_left_on_stack > 0) {
-        Register base = x10;
-        // There are always an even number of capture registers. A couple of
-        // registers determine one match with two offsets.
-        ASSERT_EQ(0, num_registers_left_on_stack % 2);
-        __ Add(base, frame_pointer(), kFirstCaptureOnStack);
-
-        // We can unroll the loop here, we should not unroll for less than 2
-        // registers.
-        STATIC_ASSERT(kNumRegistersToUnroll > 2);
-        if (num_registers_left_on_stack <= kNumRegistersToUnroll) {
-          for (int i = 0; i < num_registers_left_on_stack / 2; i++) {
-            __ Ldp(capture_end,
-                   capture_start,
-                   MemOperand(base, -kPointerSize, PostIndex));
-            if ((i == 0) && global_with_zero_length_check()) {
-              // Keep capture start for the zero-length check later.
-              __ Mov(first_capture_start, capture_start);
-            }
-            // Offsets need to be relative to the start of the string.
-            if (mode_ == UC16) {
-              __ Add(capture_start,
-                     input_length,
-                     Operand(capture_start, ASR, 1));
-              __ Add(capture_end, input_length, Operand(capture_end, ASR, 1));
-            } else {
-              __ Add(capture_start, input_length, capture_start);
-              __ Add(capture_end, input_length, capture_end);
-            }
-            // The output pointer advances for a possible global match.
-            __ Stp(capture_start,
-                   capture_end,
-                   MemOperand(output_array(), kPointerSize, PostIndex));
-          }
-        } else {
-          Label loop, start;
-          __ Mov(x11, num_registers_left_on_stack);
-
-          __ Ldp(capture_end,
-                 capture_start,
-                 MemOperand(base, -kPointerSize, PostIndex));
-          if (global_with_zero_length_check()) {
-            __ Mov(first_capture_start, capture_start);
-          }
-          __ B(&start);
-
-          __ Bind(&loop);
-          __ Ldp(capture_end,
-                 capture_start,
-                 MemOperand(base, -kPointerSize, PostIndex));
-          __ Bind(&start);
-          if (mode_ == UC16) {
-            __ Add(capture_start, input_length, Operand(capture_start, ASR, 1));
-            __ Add(capture_end, input_length, Operand(capture_end, ASR, 1));
-          } else {
-            __ Add(capture_start, input_length, capture_start);
-            __ Add(capture_end, input_length, capture_end);
-          }
-          // The output pointer advances for a possible global match.
-          __ Stp(capture_start,
-                 capture_end,
-                 MemOperand(output_array(), kPointerSize, PostIndex));
-          __ Sub(x11, x11, 2);
-          __ Cbnz(x11, &loop);
-        }
-      }
-    }
-
-    if (global()) {
-      Register success_counter = w0;
-      Register output_size = x10;
-      // Restart matching if the regular expression is flagged as global.
-
-      // Increment success counter.
-      __ Ldr(success_counter, MemOperand(frame_pointer(), kSuccessCounter));
-      __ Add(success_counter, success_counter, 1);
-      __ Str(success_counter, MemOperand(frame_pointer(), kSuccessCounter));
-
-      // Capture results have been stored, so the number of remaining global
-      // output registers is reduced by the number of stored captures.
-      __ Ldr(output_size, MemOperand(frame_pointer(), kOutputSize));
-      __ Sub(output_size, output_size, num_saved_registers_);
-      // Check whether we have enough room for another set of capture results.
-      __ Cmp(output_size, num_saved_registers_);
-      __ B(lt, &return_w0);
-
-      // The output pointer is already set to the next field in the output
-      // array.
-      // Update output size on the frame before we restart matching.
-      __ Str(output_size, MemOperand(frame_pointer(), kOutputSize));
-
-      if (global_with_zero_length_check()) {
-        // Special case for zero-length matches.
-        __ Cmp(current_input_offset(), first_capture_start);
-        // Not a zero-length match, restart.
-        __ B(ne, &load_char_start_regexp);
-        // Offset from the end is zero if we already reached the end.
-        __ Cbz(current_input_offset(), &return_w0);
-        // Advance current position after a zero-length match.
-        __ Add(current_input_offset(),
-               current_input_offset(),
-               Operand((mode_ == UC16) ? 2 : 1));
-      }
-
-      __ B(&load_char_start_regexp);
-    } else {
-      __ Mov(w0, SUCCESS);
-    }
-  }
-
-  if (exit_label_.is_linked()) {
-    // Exit and return w0
-    __ Bind(&exit_label_);
-    if (global()) {
-      __ Ldr(w0, MemOperand(frame_pointer(), kSuccessCounter));
-    }
-  }
-
-  __ Bind(&return_w0);
-
-  // Set stack pointer back to first register to retain
-  ASSERT(csp.Is(__ StackPointer()));
-  __ Mov(csp, fp);
-
-  // Restore registers.
-  __ PopCPURegList(registers_to_retain);
-
-  __ Ret();
-
-  Label exit_with_exception;
-  // Registers x0 to x7 are used to store the first captures, they need to be
-  // retained over calls to C++ code.
-  CPURegList cached_registers(CPURegister::kRegister, kXRegSizeInBits, 0, 7);
-  ASSERT((cached_registers.Count() * 2) == kNumCachedRegisters);
-
-  if (check_preempt_label_.is_linked()) {
-    __ Bind(&check_preempt_label_);
-    SaveLinkRegister();
-    // The cached registers need to be retained.
-    __ PushCPURegList(cached_registers);
-    CallCheckStackGuardState(x10);
-    // Returning from the regexp code restores the stack (csp <- fp)
-    // so we don't need to drop the link register from it before exiting.
-    __ Cbnz(w0, &return_w0);
-    // Reset the cached registers.
-    __ PopCPURegList(cached_registers);
-    RestoreLinkRegister();
-    __ Ret();
-  }
-
-  if (stack_overflow_label_.is_linked()) {
-    __ Bind(&stack_overflow_label_);
-    SaveLinkRegister();
-    // The cached registers need to be retained.
-    __ PushCPURegList(cached_registers);
-    // Call GrowStack(backtrack_stackpointer(), &stack_base)
-    __ Mov(x2, ExternalReference::isolate_address(isolate()));
-    __ Add(x1, frame_pointer(), kStackBase);
-    __ Mov(x0, backtrack_stackpointer());
-    ExternalReference grow_stack =
-        ExternalReference::re_grow_stack(isolate());
-    __ CallCFunction(grow_stack, 3);
-    // If return NULL, we have failed to grow the stack, and
-    // must exit with a stack-overflow exception.
-    // Returning from the regexp code restores the stack (csp <- fp)
-    // so we don't need to drop the link register from it before exiting.
-    __ Cbz(w0, &exit_with_exception);
-    // Otherwise use return value as new stack pointer.
-    __ Mov(backtrack_stackpointer(), x0);
-    // Reset the cached registers.
-    __ PopCPURegList(cached_registers);
-    RestoreLinkRegister();
-    __ Ret();
-  }
-
-  if (exit_with_exception.is_linked()) {
-    __ Bind(&exit_with_exception);
-    __ Mov(w0, EXCEPTION);
-    __ B(&return_w0);
-  }
-
-  CodeDesc code_desc;
-  masm_->GetCode(&code_desc);
-  Handle<Code> code = isolate()->factory()->NewCode(
-      code_desc, Code::ComputeFlags(Code::REGEXP), masm_->CodeObject());
-  PROFILE(masm_->isolate(), RegExpCodeCreateEvent(*code, *source));
-  return Handle<HeapObject>::cast(code);
-}
-
-
-void RegExpMacroAssemblerA64::GoTo(Label* to) {
-  BranchOrBacktrack(al, to);
-}
-
-void RegExpMacroAssemblerA64::IfRegisterGE(int reg,
-                                           int comparand,
-                                           Label* if_ge) {
-  Register to_compare = GetRegister(reg, w10);
-  CompareAndBranchOrBacktrack(to_compare, comparand, ge, if_ge);
-}
-
-
-void RegExpMacroAssemblerA64::IfRegisterLT(int reg,
-                                           int comparand,
-                                           Label* if_lt) {
-  Register to_compare = GetRegister(reg, w10);
-  CompareAndBranchOrBacktrack(to_compare, comparand, lt, if_lt);
-}
-
-
-void RegExpMacroAssemblerA64::IfRegisterEqPos(int reg,
-                                              Label* if_eq) {
-  Register to_compare = GetRegister(reg, w10);
-  __ Cmp(to_compare, current_input_offset());
-  BranchOrBacktrack(eq, if_eq);
-}
-
-RegExpMacroAssembler::IrregexpImplementation
-    RegExpMacroAssemblerA64::Implementation() {
-  return kA64Implementation;
-}
-
-
-void RegExpMacroAssemblerA64::LoadCurrentCharacter(int cp_offset,
-                                                   Label* on_end_of_input,
-                                                   bool check_bounds,
-                                                   int characters) {
-  // TODO(pielan): Make sure long strings are caught before this, and not
-  // just asserted in debug mode.
-  ASSERT(cp_offset >= -1);      // ^ and \b can look behind one character.
-  // Be sane! (And ensure that an int32_t can be used to index the string)
-  ASSERT(cp_offset < (1<<30));
-  if (check_bounds) {
-    CheckPosition(cp_offset + characters - 1, on_end_of_input);
-  }
-  LoadCurrentCharacterUnchecked(cp_offset, characters);
-}
-
-
-void RegExpMacroAssemblerA64::PopCurrentPosition() {
-  Pop(current_input_offset());
-}
-
-
-void RegExpMacroAssemblerA64::PopRegister(int register_index) {
-  Pop(w10);
-  StoreRegister(register_index, w10);
-}
-
-
-void RegExpMacroAssemblerA64::PushBacktrack(Label* label) {
-  if (label->is_bound()) {
-    int target = label->pos();
-    __ Mov(w10, target + Code::kHeaderSize - kHeapObjectTag);
-  } else {
-    __ Adr(x10, label);
-    __ Sub(x10, x10, code_pointer());
-    if (masm_->emit_debug_code()) {
-      __ Cmp(x10, kWRegMask);
-      // The code offset has to fit in a W register.
-      __ Check(ls, kOffsetOutOfRange);
-    }
-  }
-  Push(w10);
-  CheckStackLimit();
-}
-
-
-void RegExpMacroAssemblerA64::PushCurrentPosition() {
-  Push(current_input_offset());
-}
-
-
-void RegExpMacroAssemblerA64::PushRegister(int register_index,
-                                           StackCheckFlag check_stack_limit) {
-  Register to_push = GetRegister(register_index, w10);
-  Push(to_push);
-  if (check_stack_limit) CheckStackLimit();
-}
-
-
-void RegExpMacroAssemblerA64::ReadCurrentPositionFromRegister(int reg) {
-  Register cached_register;
-  RegisterState register_state = GetRegisterState(reg);
-  switch (register_state) {
-    case STACKED:
-      __ Ldr(current_input_offset(), register_location(reg));
-      break;
-    case CACHED_LSW:
-      cached_register = GetCachedRegister(reg);
-      __ Mov(current_input_offset(), cached_register.W());
-      break;
-    case CACHED_MSW:
-      cached_register = GetCachedRegister(reg);
-      __ Lsr(current_input_offset().X(), cached_register, kWRegSizeInBits);
-      break;
-    default:
-      UNREACHABLE();
-      break;
-  }
-}
-
-
-void RegExpMacroAssemblerA64::ReadStackPointerFromRegister(int reg) {
-  Register read_from = GetRegister(reg, w10);
-  __ Ldr(x11, MemOperand(frame_pointer(), kStackBase));
-  __ Add(backtrack_stackpointer(), x11, Operand(read_from, SXTW));
-}
-
-
-void RegExpMacroAssemblerA64::SetCurrentPositionFromEnd(int by) {
-  Label after_position;
-  __ Cmp(current_input_offset(), -by * char_size());
-  __ B(ge, &after_position);
-  __ Mov(current_input_offset(), -by * char_size());
-  // On RegExp code entry (where this operation is used), the character before
-  // the current position is expected to be already loaded.
-  // We have advanced the position, so it's safe to read backwards.
-  LoadCurrentCharacterUnchecked(-1, 1);
-  __ Bind(&after_position);
-}
-
-
-void RegExpMacroAssemblerA64::SetRegister(int register_index, int to) {
-  ASSERT(register_index >= num_saved_registers_);  // Reserved for positions!
-  Register set_to = wzr;
-  if (to != 0) {
-    set_to = w10;
-    __ Mov(set_to, to);
-  }
-  StoreRegister(register_index, set_to);
-}
-
-
-bool RegExpMacroAssemblerA64::Succeed() {
-  __ B(&success_label_);
-  return global();
-}
-
-
-void RegExpMacroAssemblerA64::WriteCurrentPositionToRegister(int reg,
-                                                             int cp_offset) {
-  Register position = current_input_offset();
-  if (cp_offset != 0) {
-    position = w10;
-    __ Add(position, current_input_offset(), cp_offset * char_size());
-  }
-  StoreRegister(reg, position);
-}
-
-
-void RegExpMacroAssemblerA64::ClearRegisters(int reg_from, int reg_to) {
-  ASSERT(reg_from <= reg_to);
-  int num_registers = reg_to - reg_from + 1;
-
-  // If the first capture register is cached in a hardware register but not
-  // aligned on a 64-bit one, we need to clear the first one specifically.
-  if ((reg_from < kNumCachedRegisters) && ((reg_from % 2) != 0)) {
-    StoreRegister(reg_from, non_position_value());
-    num_registers--;
-    reg_from++;
-  }
-
-  // Clear cached registers in pairs as far as possible.
-  while ((num_registers >= 2) && (reg_from < kNumCachedRegisters)) {
-    ASSERT(GetRegisterState(reg_from) == CACHED_LSW);
-    __ Mov(GetCachedRegister(reg_from), twice_non_position_value());
-    reg_from += 2;
-    num_registers -= 2;
-  }
-
-  if ((num_registers % 2) == 1) {
-    StoreRegister(reg_from, non_position_value());
-    num_registers--;
-    reg_from++;
-  }
-
-  if (num_registers > 0) {
-    // If there are some remaining registers, they are stored on the stack.
-    ASSERT(reg_from >= kNumCachedRegisters);
-
-    // Move down the indexes of the registers on stack to get the correct offset
-    // in memory.
-    reg_from -= kNumCachedRegisters;
-    reg_to -= kNumCachedRegisters;
-    // We should not unroll the loop for less than 2 registers.
-    STATIC_ASSERT(kNumRegistersToUnroll > 2);
-    // We position the base pointer to (reg_from + 1).
-    int base_offset = kFirstRegisterOnStack -
-        kWRegSize - (kWRegSize * reg_from);
-    if (num_registers > kNumRegistersToUnroll) {
-      Register base = x10;
-      __ Add(base, frame_pointer(), base_offset);
-
-      Label loop;
-      __ Mov(x11, num_registers);
-      __ Bind(&loop);
-      __ Str(twice_non_position_value(),
-             MemOperand(base, -kPointerSize, PostIndex));
-      __ Sub(x11, x11, 2);
-      __ Cbnz(x11, &loop);
-    } else {
-      for (int i = reg_from; i <= reg_to; i += 2) {
-        __ Str(twice_non_position_value(),
-               MemOperand(frame_pointer(), base_offset));
-        base_offset -= kWRegSize * 2;
-      }
-    }
-  }
-}
-
-
-void RegExpMacroAssemblerA64::WriteStackPointerToRegister(int reg) {
-  __ Ldr(x10, MemOperand(frame_pointer(), kStackBase));
-  __ Sub(x10, backtrack_stackpointer(), x10);
-  if (masm_->emit_debug_code()) {
-    __ Cmp(x10, Operand(w10, SXTW));
-    // The stack offset needs to fit in a W register.
-    __ Check(eq, kOffsetOutOfRange);
-  }
-  StoreRegister(reg, w10);
-}
-
-
-// Helper function for reading a value out of a stack frame.
-template <typename T>
-static T& frame_entry(Address re_frame, int frame_offset) {
-  return *reinterpret_cast<T*>(re_frame + frame_offset);
-}
-
-
-int RegExpMacroAssemblerA64::CheckStackGuardState(Address* return_address,
-                                                  Code* re_code,
-                                                  Address re_frame,
-                                                  int start_offset,
-                                                  const byte** input_start,
-                                                  const byte** input_end) {
-  Isolate* isolate = frame_entry<Isolate*>(re_frame, kIsolate);
-  if (isolate->stack_guard()->IsStackOverflow()) {
-    isolate->StackOverflow();
-    return EXCEPTION;
-  }
-
-  // If not real stack overflow the stack guard was used to interrupt
-  // execution for another purpose.
-
-  // If this is a direct call from JavaScript retry the RegExp forcing the call
-  // through the runtime system. Currently the direct call cannot handle a GC.
-  if (frame_entry<int>(re_frame, kDirectCall) == 1) {
-    return RETRY;
-  }
-
-  // Prepare for possible GC.
-  HandleScope handles(isolate);
-  Handle<Code> code_handle(re_code);
-
-  Handle<String> subject(frame_entry<String*>(re_frame, kInput));
-
-  // Current string.
-  bool is_ascii = subject->IsOneByteRepresentationUnderneath();
-
-  ASSERT(re_code->instruction_start() <= *return_address);
-  ASSERT(*return_address <=
-      re_code->instruction_start() + re_code->instruction_size());
-
-  MaybeObject* result = Execution::HandleStackGuardInterrupt(isolate);
-
-  if (*code_handle != re_code) {  // Return address no longer valid
-    int delta = code_handle->address() - re_code->address();
-    // Overwrite the return address on the stack.
-    *return_address += delta;
-  }
-
-  if (result->IsException()) {
-    return EXCEPTION;
-  }
-
-  Handle<String> subject_tmp = subject;
-  int slice_offset = 0;
-
-  // Extract the underlying string and the slice offset.
-  if (StringShape(*subject_tmp).IsCons()) {
-    subject_tmp = Handle<String>(ConsString::cast(*subject_tmp)->first());
-  } else if (StringShape(*subject_tmp).IsSliced()) {
-    SlicedString* slice = SlicedString::cast(*subject_tmp);
-    subject_tmp = Handle<String>(slice->parent());
-    slice_offset = slice->offset();
-  }
-
-  // String might have changed.
-  if (subject_tmp->IsOneByteRepresentation() != is_ascii) {
-    // If we changed between an ASCII and an UC16 string, the specialized
-    // code cannot be used, and we need to restart regexp matching from
-    // scratch (including, potentially, compiling a new version of the code).
-    return RETRY;
-  }
-
-  // Otherwise, the content of the string might have moved. It must still
-  // be a sequential or external string with the same content.
-  // Update the start and end pointers in the stack frame to the current
-  // location (whether it has actually moved or not).
-  ASSERT(StringShape(*subject_tmp).IsSequential() ||
-         StringShape(*subject_tmp).IsExternal());
-
-  // The original start address of the characters to match.
-  const byte* start_address = *input_start;
-
-  // Find the current start address of the same character at the current string
-  // position.
-  const byte* new_address = StringCharacterPosition(*subject_tmp,
-      start_offset + slice_offset);
-
-  if (start_address != new_address) {
-    // If there is a difference, update the object pointer and start and end
-    // addresses in the RegExp stack frame to match the new value.
-    const byte* end_address = *input_end;
-    int byte_length = static_cast<int>(end_address - start_address);
-    frame_entry<const String*>(re_frame, kInput) = *subject;
-    *input_start = new_address;
-    *input_end = new_address + byte_length;
-  } else if (frame_entry<const String*>(re_frame, kInput) != *subject) {
-    // Subject string might have been a ConsString that underwent
-    // short-circuiting during GC. That will not change start_address but
-    // will change pointer inside the subject handle.
-    frame_entry<const String*>(re_frame, kInput) = *subject;
-  }
-
-  return 0;
-}
-
-
-void RegExpMacroAssemblerA64::CheckPosition(int cp_offset,
-                                            Label* on_outside_input) {
-  CompareAndBranchOrBacktrack(current_input_offset(),
-                              -cp_offset * char_size(),
-                              ge,
-                              on_outside_input);
-}
-
-
-bool RegExpMacroAssemblerA64::CanReadUnaligned() {
-  // TODO(pielan): See whether or not we should disable unaligned accesses.
-  return !slow_safe();
-}
-
-
-// Private methods:
-
-void RegExpMacroAssemblerA64::CallCheckStackGuardState(Register scratch) {
-  // Allocate space on the stack to store the return address. The
-  // CheckStackGuardState C++ function will override it if the code
-  // moved. Allocate extra space for 2 arguments passed by pointers.
-  // AAPCS64 requires the stack to be 16 byte aligned.
-  int alignment = masm_->ActivationFrameAlignment();
-  ASSERT_EQ(alignment % 16, 0);
-  int align_mask = (alignment / kXRegSize) - 1;
-  int xreg_to_claim = (3 + align_mask) & ~align_mask;
-
-  ASSERT(csp.Is(__ StackPointer()));
-  __ Claim(xreg_to_claim);
-
-  // CheckStackGuardState needs the end and start addresses of the input string.
-  __ Poke(input_end(), 2 * kPointerSize);
-  __ Add(x5, csp, 2 * kPointerSize);
-  __ Poke(input_start(), kPointerSize);
-  __ Add(x4, csp, kPointerSize);
-
-  __ Mov(w3, start_offset());
-  // RegExp code frame pointer.
-  __ Mov(x2, frame_pointer());
-  // Code* of self.
-  __ Mov(x1, Operand(masm_->CodeObject()));
-
-  // We need to pass a pointer to the return address as first argument.
-  // The DirectCEntry stub will place the return address on the stack before
-  // calling so the stack pointer will point to it.
-  __ Mov(x0, csp);
-
-  ExternalReference check_stack_guard_state =
-      ExternalReference::re_check_stack_guard_state(isolate());
-  __ Mov(scratch, check_stack_guard_state);
-  DirectCEntryStub stub;
-  stub.GenerateCall(masm_, scratch);
-
-  // The input string may have been moved in memory, we need to reload it.
-  __ Peek(input_start(), kPointerSize);
-  __ Peek(input_end(), 2 * kPointerSize);
-
-  ASSERT(csp.Is(__ StackPointer()));
-  __ Drop(xreg_to_claim);
-
-  // Reload the Code pointer.
-  __ Mov(code_pointer(), Operand(masm_->CodeObject()));
-}
-
-void RegExpMacroAssemblerA64::BranchOrBacktrack(Condition condition,
-                                                Label* to) {
-  if (condition == al) {  // Unconditional.
-    if (to == NULL) {
-      Backtrack();
-      return;
-    }
-    __ B(to);
-    return;
-  }
-  if (to == NULL) {
-    to = &backtrack_label_;
-  }
-  // TODO(ulan): do direct jump when jump distance is known and fits in imm19.
-  Condition inverted_condition = InvertCondition(condition);
-  Label no_branch;
-  __ B(inverted_condition, &no_branch);
-  __ B(to);
-  __ Bind(&no_branch);
-}
-
-void RegExpMacroAssemblerA64::CompareAndBranchOrBacktrack(Register reg,
-                                                          int immediate,
-                                                          Condition condition,
-                                                          Label* to) {
-  if ((immediate == 0) && ((condition == eq) || (condition == ne))) {
-    if (to == NULL) {
-      to = &backtrack_label_;
-    }
-    // TODO(ulan): do direct jump when jump distance is known and fits in imm19.
-    Label no_branch;
-    if (condition == eq) {
-      __ Cbnz(reg, &no_branch);
-    } else {
-      __ Cbz(reg, &no_branch);
-    }
-    __ B(to);
-    __ Bind(&no_branch);
-  } else {
-    __ Cmp(reg, immediate);
-    BranchOrBacktrack(condition, to);
-  }
-}
-
-
-void RegExpMacroAssemblerA64::CheckPreemption() {
-  // Check for preemption.
-  ExternalReference stack_limit =
-      ExternalReference::address_of_stack_limit(isolate());
-  __ Mov(x10, stack_limit);
-  __ Ldr(x10, MemOperand(x10));
-  ASSERT(csp.Is(__ StackPointer()));
-  __ Cmp(csp, x10);
-  CallIf(&check_preempt_label_, ls);
-}
-
-
-void RegExpMacroAssemblerA64::CheckStackLimit() {
-  ExternalReference stack_limit =
-      ExternalReference::address_of_regexp_stack_limit(isolate());
-  __ Mov(x10, stack_limit);
-  __ Ldr(x10, MemOperand(x10));
-  __ Cmp(backtrack_stackpointer(), x10);
-  CallIf(&stack_overflow_label_, ls);
-}
-
-
-void RegExpMacroAssemblerA64::Push(Register source) {
-  ASSERT(source.Is32Bits());
-  ASSERT(!source.is(backtrack_stackpointer()));
-  __ Str(source,
-         MemOperand(backtrack_stackpointer(),
-                    -static_cast<int>(kWRegSize),
-                    PreIndex));
-}
-
-
-void RegExpMacroAssemblerA64::Pop(Register target) {
-  ASSERT(target.Is32Bits());
-  ASSERT(!target.is(backtrack_stackpointer()));
-  __ Ldr(target,
-         MemOperand(backtrack_stackpointer(), kWRegSize, PostIndex));
-}
-
-
-Register RegExpMacroAssemblerA64::GetCachedRegister(int register_index) {
-  ASSERT(register_index < kNumCachedRegisters);
-  return Register::Create(register_index / 2, kXRegSizeInBits);
-}
-
-
-Register RegExpMacroAssemblerA64::GetRegister(int register_index,
-                                              Register maybe_result) {
-  ASSERT(maybe_result.Is32Bits());
-  ASSERT(register_index >= 0);
-  if (num_registers_ <= register_index) {
-    num_registers_ = register_index + 1;
-  }
-  Register result;
-  RegisterState register_state = GetRegisterState(register_index);
-  switch (register_state) {
-    case STACKED:
-      __ Ldr(maybe_result, register_location(register_index));
-      result = maybe_result;
-      break;
-    case CACHED_LSW:
-      result = GetCachedRegister(register_index).W();
-      break;
-    case CACHED_MSW:
-      __ Lsr(maybe_result.X(), GetCachedRegister(register_index),
-             kWRegSizeInBits);
-      result = maybe_result;
-      break;
-    default:
-      UNREACHABLE();
-      break;
-  }
-  ASSERT(result.Is32Bits());
-  return result;
-}
-
-
-void RegExpMacroAssemblerA64::StoreRegister(int register_index,
-                                            Register source) {
-  ASSERT(source.Is32Bits());
-  ASSERT(register_index >= 0);
-  if (num_registers_ <= register_index) {
-    num_registers_ = register_index + 1;
-  }
-
-  Register cached_register;
-  RegisterState register_state = GetRegisterState(register_index);
-  switch (register_state) {
-    case STACKED:
-      __ Str(source, register_location(register_index));
-      break;
-    case CACHED_LSW:
-      cached_register = GetCachedRegister(register_index);
-      if (!source.Is(cached_register.W())) {
-        __ Bfi(cached_register, source.X(), 0, kWRegSizeInBits);
-      }
-      break;
-    case CACHED_MSW:
-      cached_register = GetCachedRegister(register_index);
-      __ Bfi(cached_register, source.X(), kWRegSizeInBits, kWRegSizeInBits);
-      break;
-    default:
-      UNREACHABLE();
-      break;
-  }
-}
-
-
-void RegExpMacroAssemblerA64::CallIf(Label* to, Condition condition) {
-  Label skip_call;
-  if (condition != al) __ B(&skip_call, InvertCondition(condition));
-  __ Bl(to);
-  __ Bind(&skip_call);
-}
-
-
-void RegExpMacroAssemblerA64::RestoreLinkRegister() {
-  ASSERT(csp.Is(__ StackPointer()));
-  __ Pop(lr, xzr);
-  __ Add(lr, lr, Operand(masm_->CodeObject()));
-}
-
-
-void RegExpMacroAssemblerA64::SaveLinkRegister() {
-  ASSERT(csp.Is(__ StackPointer()));
-  __ Sub(lr, lr, Operand(masm_->CodeObject()));
-  __ Push(xzr, lr);
-}
-
-
-MemOperand RegExpMacroAssemblerA64::register_location(int register_index) {
-  ASSERT(register_index < (1<<30));
-  ASSERT(register_index >= kNumCachedRegisters);
-  if (num_registers_ <= register_index) {
-    num_registers_ = register_index + 1;
-  }
-  register_index -= kNumCachedRegisters;
-  int offset = kFirstRegisterOnStack - register_index * kWRegSize;
-  return MemOperand(frame_pointer(), offset);
-}
-
-MemOperand RegExpMacroAssemblerA64::capture_location(int register_index,
-                                                     Register scratch) {
-  ASSERT(register_index < (1<<30));
-  ASSERT(register_index < num_saved_registers_);
-  ASSERT(register_index >= kNumCachedRegisters);
-  ASSERT_EQ(register_index % 2, 0);
-  register_index -= kNumCachedRegisters;
-  int offset = kFirstCaptureOnStack - register_index * kWRegSize;
-  // capture_location is used with Stp instructions to load/store 2 registers.
-  // The immediate field in the encoding is limited to 7 bits (signed).
-  if (is_int7(offset)) {
-    return MemOperand(frame_pointer(), offset);
-  } else {
-    __ Add(scratch, frame_pointer(), offset);
-    return MemOperand(scratch);
-  }
-}
-
-void RegExpMacroAssemblerA64::LoadCurrentCharacterUnchecked(int cp_offset,
-                                                            int characters) {
-  Register offset = current_input_offset();
-
-  // The ldr, str, ldrh, strh instructions can do unaligned accesses, if the CPU
-  // and the operating system running on the target allow it.
-  // If unaligned load/stores are not supported then this function must only
-  // be used to load a single character at a time.
-
-  // ARMv8 supports unaligned accesses but V8 or the kernel can decide to
-  // disable it.
-  // TODO(pielan): See whether or not we should disable unaligned accesses.
-  if (!CanReadUnaligned()) {
-    ASSERT(characters == 1);
-  }
-
-  if (cp_offset != 0) {
-    if (masm_->emit_debug_code()) {
-      __ Mov(x10, cp_offset * char_size());
-      __ Add(x10, x10, Operand(current_input_offset(), SXTW));
-      __ Cmp(x10, Operand(w10, SXTW));
-      // The offset needs to fit in a W register.
-      __ Check(eq, kOffsetOutOfRange);
-    } else {
-      __ Add(w10, current_input_offset(), cp_offset * char_size());
-    }
-    offset = w10;
-  }
-
-  if (mode_ == ASCII) {
-    if (characters == 4) {
-      __ Ldr(current_character(), MemOperand(input_end(), offset, SXTW));
-    } else if (characters == 2) {
-      __ Ldrh(current_character(), MemOperand(input_end(), offset, SXTW));
-    } else {
-      ASSERT(characters == 1);
-      __ Ldrb(current_character(), MemOperand(input_end(), offset, SXTW));
-    }
-  } else {
-    ASSERT(mode_ == UC16);
-    if (characters == 2) {
-      __ Ldr(current_character(), MemOperand(input_end(), offset, SXTW));
-    } else {
-      ASSERT(characters == 1);
-      __ Ldrh(current_character(), MemOperand(input_end(), offset, SXTW));
-    }
-  }
-}
-
-#endif  // V8_INTERPRETED_REGEXP
-
-}}  // namespace v8::internal
-
-#endif  // V8_TARGET_ARCH_A64