Merge experimental/a64 to bleeding_edge.

src/a64/macro-assembler-a64.cc

Index: src/a64/macro-assembler-a64.cc
diff --git a/src/a64/macro-assembler-a64.cc b/src/a64/macro-assembler-a64.cc
new file mode 100644
index 0000000000000000000000000000000000000000..b51e9277c4e4969212417284b84033a4dc60c1e4
--- /dev/null
+++ b/src/a64/macro-assembler-a64.cc
@@ -0,0 +1,4806 @@
+// 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 "bootstrapper.h"
+#include "codegen.h"
+#include "cpu-profiler.h"
+#include "debug.h"
+#include "isolate-inl.h"
+#include "runtime.h"
+
+namespace v8 {
+namespace internal {
+
+// Define a fake double underscore to use with the ASM_UNIMPLEMENTED macros.
+#define __
+
+
+MacroAssembler::MacroAssembler(Isolate* arg_isolate,
+                               byte * buffer,
+                               unsigned buffer_size)
+    : Assembler(arg_isolate, buffer, buffer_size),
+      generating_stub_(false),
+#if DEBUG
+      allow_macro_instructions_(true),
+#endif
+      has_frame_(false),
+      use_real_aborts_(true),
+      sp_(jssp), tmp0_(ip0), tmp1_(ip1), fptmp0_(fp_scratch) {
+  if (isolate() != NULL) {
+    code_object_ = Handle<Object>(isolate()->heap()->undefined_value(),
+                                  isolate());
+  }
+}
+
+
+void MacroAssembler::LogicalMacro(const Register& rd,
+                                  const Register& rn,
+                                  const Operand& operand,
+                                  LogicalOp op) {
+  if (operand.NeedsRelocation()) {
+    LoadRelocated(Tmp0(), operand);
+    Logical(rd, rn, Tmp0(), op);
+
+  } else if (operand.IsImmediate()) {
+    int64_t immediate = operand.immediate();
+    unsigned reg_size = rd.SizeInBits();
+    ASSERT(rd.Is64Bits() || is_uint32(immediate));
+
+    // If the operation is NOT, invert the operation and immediate.
+    if ((op & NOT) == NOT) {
+      op = static_cast<LogicalOp>(op & ~NOT);
+      immediate = ~immediate;
+      if (rd.Is32Bits()) {
+        immediate &= kWRegMask;
+      }
+    }
+
+    // Special cases for all set or all clear immediates.
+    if (immediate == 0) {
+      switch (op) {
+        case AND:
+          Mov(rd, 0);
+          return;
+        case ORR:  // Fall through.
+        case EOR:
+          Mov(rd, rn);
+          return;
+        case ANDS:  // Fall through.
+        case BICS:
+          break;
+        default:
+          UNREACHABLE();
+      }
+    } else if ((rd.Is64Bits() && (immediate == -1L)) ||
+               (rd.Is32Bits() && (immediate == 0xffffffffL))) {
+      switch (op) {
+        case AND:
+          Mov(rd, rn);
+          return;
+        case ORR:
+          Mov(rd, immediate);
+          return;
+        case EOR:
+          Mvn(rd, rn);
+          return;
+        case ANDS:  // Fall through.
+        case BICS:
+          break;
+        default:
+          UNREACHABLE();
+      }
+    }
+
+    unsigned n, imm_s, imm_r;
+    if (IsImmLogical(immediate, reg_size, &n, &imm_s, &imm_r)) {
+      // Immediate can be encoded in the instruction.
+      LogicalImmediate(rd, rn, n, imm_s, imm_r, op);
+    } else {
+      // Immediate can't be encoded: synthesize using move immediate.
+      Register temp = AppropriateTempFor(rn);
+      Mov(temp, immediate);
+      if (rd.Is(csp)) {
+        // If rd is the stack pointer we cannot use it as the destination
+        // register so we use the temp register as an intermediate again.
+        Logical(temp, rn, temp, op);
+        Mov(csp, temp);
+      } else {
+        Logical(rd, rn, temp, op);
+      }
+    }
+
+  } else if (operand.IsExtendedRegister()) {
+    ASSERT(operand.reg().SizeInBits() <= rd.SizeInBits());
+    // Add/sub extended supports shift <= 4. We want to support exactly the
+    // same modes here.
+    ASSERT(operand.shift_amount() <= 4);
+    ASSERT(operand.reg().Is64Bits() ||
+           ((operand.extend() != UXTX) && (operand.extend() != SXTX)));
+    Register temp = AppropriateTempFor(rn, operand.reg());
+    EmitExtendShift(temp, operand.reg(), operand.extend(),
+                    operand.shift_amount());
+    Logical(rd, rn, temp, op);
+
+  } else {
+    // The operand can be encoded in the instruction.
+    ASSERT(operand.IsShiftedRegister());
+    Logical(rd, rn, operand, op);
+  }
+}
+
+
+void MacroAssembler::Mov(const Register& rd, uint64_t imm) {
+  ASSERT(allow_macro_instructions_);
+  ASSERT(is_uint32(imm) || is_int32(imm) || rd.Is64Bits());
+  ASSERT(!rd.IsZero());
+
+  // TODO(all) extend to support more immediates.
+  //
+  // Immediates on Aarch64 can be produced using an initial value, and zero to
+  // three move keep operations.
+  //
+  // Initial values can be generated with:
+  //  1. 64-bit move zero (movz).
+  //  2. 32-bit move inverted (movn).
+  //  3. 64-bit move inverted.
+  //  4. 32-bit orr immediate.
+  //  5. 64-bit orr immediate.
+  // Move-keep may then be used to modify each of the 16-bit half-words.
+  //
+  // The code below supports all five initial value generators, and
+  // applying move-keep operations to move-zero and move-inverted initial
+  // values.
+
+  unsigned reg_size = rd.SizeInBits();
+  unsigned n, imm_s, imm_r;
+  if (IsImmMovz(imm, reg_size) && !rd.IsSP()) {
+    // Immediate can be represented in a move zero instruction. Movz can't
+    // write to the stack pointer.
+    movz(rd, imm);
+  } else if (IsImmMovn(imm, reg_size) && !rd.IsSP()) {
+    // Immediate can be represented in a move inverted instruction. Movn can't
+    // write to the stack pointer.
+    movn(rd, rd.Is64Bits() ? ~imm : (~imm & kWRegMask));
+  } else if (IsImmLogical(imm, reg_size, &n, &imm_s, &imm_r)) {
+    // Immediate can be represented in a logical orr instruction.
+    LogicalImmediate(rd, AppropriateZeroRegFor(rd), n, imm_s, imm_r, ORR);
+  } else {
+    // Generic immediate case. Imm will be represented by
+    //   [imm3, imm2, imm1, imm0], where each imm is 16 bits.
+    // A move-zero or move-inverted is generated for the first non-zero or
+    // non-0xffff immX, and a move-keep for subsequent non-zero immX.
+
+    uint64_t ignored_halfword = 0;
+    bool invert_move = false;
+    // If the number of 0xffff halfwords is greater than the number of 0x0000
+    // halfwords, it's more efficient to use move-inverted.
+    if (CountClearHalfWords(~imm, reg_size) >
+        CountClearHalfWords(imm, reg_size)) {
+      ignored_halfword = 0xffffL;
+      invert_move = true;
+    }
+
+    // Mov instructions can't move value into the stack pointer, so set up a
+    // temporary register, if needed.
+    Register temp = rd.IsSP() ? AppropriateTempFor(rd) : rd;
+
+    // Iterate through the halfwords. Use movn/movz for the first non-ignored
+    // halfword, and movk for subsequent halfwords.
+    ASSERT((reg_size % 16) == 0);
+    bool first_mov_done = false;
+    for (unsigned i = 0; i < (rd.SizeInBits() / 16); i++) {
+      uint64_t imm16 = (imm >> (16 * i)) & 0xffffL;
+      if (imm16 != ignored_halfword) {
+        if (!first_mov_done) {
+          if (invert_move) {
+            movn(temp, (~imm16) & 0xffffL, 16 * i);
+          } else {
+            movz(temp, imm16, 16 * i);
+          }
+          first_mov_done = true;
+        } else {
+          // Construct a wider constant.
+          movk(temp, imm16, 16 * i);
+        }
+      }
+    }
+    ASSERT(first_mov_done);
+
+    // Move the temporary if the original destination register was the stack
+    // pointer.
+    if (rd.IsSP()) {
+      mov(rd, temp);
+    }
+  }
+}
+
+
+void MacroAssembler::Mov(const Register& rd,
+                         const Operand& operand,
+                         DiscardMoveMode discard_mode) {
+  ASSERT(allow_macro_instructions_);
+  ASSERT(!rd.IsZero());
+  // Provide a swap register for instructions that need to write into the
+  // system stack pointer (and can't do this inherently).
+  Register dst = (rd.Is(csp)) ? (Tmp1()) : (rd);
+
+  if (operand.NeedsRelocation()) {
+    LoadRelocated(dst, operand);
+
+  } else if (operand.IsImmediate()) {
+    // Call the macro assembler for generic immediates.
+    Mov(dst, operand.immediate());
+
+  } else if (operand.IsShiftedRegister() && (operand.shift_amount() != 0)) {
+    // Emit a shift instruction if moving a shifted register. This operation
+    // could also be achieved using an orr instruction (like orn used by Mvn),
+    // but using a shift instruction makes the disassembly clearer.
+    EmitShift(dst, operand.reg(), operand.shift(), operand.shift_amount());
+
+  } else if (operand.IsExtendedRegister()) {
+    // Emit an extend instruction if moving an extended register. This handles
+    // extend with post-shift operations, too.
+    EmitExtendShift(dst, operand.reg(), operand.extend(),
+                    operand.shift_amount());
+
+  } else {
+    // Otherwise, emit a register move only if the registers are distinct, or
+    // if they are not X registers.
+    //
+    // Note that mov(w0, w0) is not a no-op because it clears the top word of
+    // x0. A flag is provided (kDiscardForSameWReg) if a move between the same W
+    // registers is not required to clear the top word of the X register. In
+    // this case, the instruction is discarded.
+    //
+    // If csp is an operand, add #0 is emitted, otherwise, orr #0.
+    if (!rd.Is(operand.reg()) || (rd.Is32Bits() &&
+                                  (discard_mode == kDontDiscardForSameWReg))) {
+      Assembler::mov(rd, operand.reg());
+    }
+    // This case can handle writes into the system stack pointer directly.
+    dst = rd;
+  }
+
+  // Copy the result to the system stack pointer.
+  if (!dst.Is(rd)) {
+    ASSERT(rd.IsZero());
+    ASSERT(dst.Is(Tmp1()));
+    Assembler::mov(rd, dst);
+  }
+}
+
+
+void MacroAssembler::Mvn(const Register& rd, const Operand& operand) {
+  ASSERT(allow_macro_instructions_);
+
+  if (operand.NeedsRelocation()) {
+    LoadRelocated(Tmp0(), operand);
+    Mvn(rd, Tmp0());
+
+  } else if (operand.IsImmediate()) {
+    // Call the macro assembler for generic immediates.
+    Mov(rd, ~operand.immediate());
+
+  } else if (operand.IsExtendedRegister()) {
+    // Emit two instructions for the extend case. This differs from Mov, as
+    // the extend and invert can't be achieved in one instruction.
+    Register temp = AppropriateTempFor(rd, operand.reg());
+    EmitExtendShift(temp, operand.reg(), operand.extend(),
+                    operand.shift_amount());
+    mvn(rd, temp);
+
+  } else {
+    // Otherwise, emit a register move only if the registers are distinct.
+    // If the jssp is an operand, add #0 is emitted, otherwise, orr #0.
+    mvn(rd, operand);
+  }
+}
+
+
+unsigned MacroAssembler::CountClearHalfWords(uint64_t imm, unsigned reg_size) {
+  ASSERT((reg_size % 8) == 0);
+  int count = 0;
+  for (unsigned i = 0; i < (reg_size / 16); i++) {
+    if ((imm & 0xffff) == 0) {
+      count++;
+    }
+    imm >>= 16;
+  }
+  return count;
+}
+
+
+// The movz instruction can generate immediates containing an arbitrary 16-bit
+// half-word, with remaining bits clear, eg. 0x00001234, 0x0000123400000000.
+bool MacroAssembler::IsImmMovz(uint64_t imm, unsigned reg_size) {
+  ASSERT((reg_size == kXRegSize) || (reg_size == kWRegSize));
+  return CountClearHalfWords(imm, reg_size) >= ((reg_size / 16) - 1);
+}
+
+
+// The movn instruction can generate immediates containing an arbitrary 16-bit
+// half-word, with remaining bits set, eg. 0xffff1234, 0xffff1234ffffffff.
+bool MacroAssembler::IsImmMovn(uint64_t imm, unsigned reg_size) {
+  return IsImmMovz(~imm, reg_size);
+}
+
+
+void MacroAssembler::ConditionalCompareMacro(const Register& rn,
+                                             const Operand& operand,
+                                             StatusFlags nzcv,
+                                             Condition cond,
+                                             ConditionalCompareOp op) {
+  ASSERT((cond != al) && (cond != nv));
+  if (operand.NeedsRelocation()) {
+    LoadRelocated(Tmp0(), operand);
+    ConditionalCompareMacro(rn, Tmp0(), nzcv, cond, op);
+
+  } else if ((operand.IsShiftedRegister() && (operand.shift_amount() == 0)) ||
+      (operand.IsImmediate() && IsImmConditionalCompare(operand.immediate()))) {
+    // The immediate can be encoded in the instruction, or the operand is an
+    // unshifted register: call the assembler.
+    ConditionalCompare(rn, operand, nzcv, cond, op);
+
+  } else {
+    // The operand isn't directly supported by the instruction: perform the
+    // operation on a temporary register.
+    Register temp = AppropriateTempFor(rn);
+    Mov(temp, operand);
+    ConditionalCompare(rn, temp, nzcv, cond, op);
+  }
+}
+
+
+void MacroAssembler::Csel(const Register& rd,
+                          const Register& rn,
+                          const Operand& operand,
+                          Condition cond) {
+  ASSERT(allow_macro_instructions_);
+  ASSERT(!rd.IsZero());
+  ASSERT((cond != al) && (cond != nv));
+  if (operand.IsImmediate()) {
+    // Immediate argument. Handle special cases of 0, 1 and -1 using zero
+    // register.
+    int64_t imm = operand.immediate();
+    Register zr = AppropriateZeroRegFor(rn);
+    if (imm == 0) {
+      csel(rd, rn, zr, cond);
+    } else if (imm == 1) {
+      csinc(rd, rn, zr, cond);
+    } else if (imm == -1) {
+      csinv(rd, rn, zr, cond);
+    } else {
+      Register temp = AppropriateTempFor(rn);
+      Mov(temp, operand.immediate());
+      csel(rd, rn, temp, cond);
+    }
+  } else if (operand.IsShiftedRegister() && (operand.shift_amount() == 0)) {
+    // Unshifted register argument.
+    csel(rd, rn, operand.reg(), cond);
+  } else {
+    // All other arguments.
+    Register temp = AppropriateTempFor(rn);
+    Mov(temp, operand);
+    csel(rd, rn, temp, cond);
+  }
+}
+
+
+void MacroAssembler::AddSubMacro(const Register& rd,
+                                 const Register& rn,
+                                 const Operand& operand,
+                                 FlagsUpdate S,
+                                 AddSubOp op) {
+  if (operand.IsZero() && rd.Is(rn) && rd.Is64Bits() && rn.Is64Bits() &&
+      !operand.NeedsRelocation() && (S == LeaveFlags)) {
+    // The instruction would be a nop. Avoid generating useless code.
+    return;
+  }
+
+  if (operand.NeedsRelocation()) {
+    LoadRelocated(Tmp0(), operand);
+    AddSubMacro(rd, rn, Tmp0(), S, op);
+  } else if ((operand.IsImmediate() && !IsImmAddSub(operand.immediate())) ||
+             (rn.IsZero() && !operand.IsShiftedRegister())                ||
+             (operand.IsShiftedRegister() && (operand.shift() == ROR))) {
+    Register temp = AppropriateTempFor(rn);
+    Mov(temp, operand);
+    AddSub(rd, rn, temp, S, op);
+  } else {
+    AddSub(rd, rn, operand, S, op);
+  }
+}
+
+
+void MacroAssembler::AddSubWithCarryMacro(const Register& rd,
+                                          const Register& rn,
+                                          const Operand& operand,
+                                          FlagsUpdate S,
+                                          AddSubWithCarryOp op) {
+  ASSERT(rd.SizeInBits() == rn.SizeInBits());
+
+  if (operand.NeedsRelocation()) {
+    LoadRelocated(Tmp0(), operand);
+    AddSubWithCarryMacro(rd, rn, Tmp0(), S, op);
+
+  } else if (operand.IsImmediate() ||
+             (operand.IsShiftedRegister() && (operand.shift() == ROR))) {
+    // Add/sub with carry (immediate or ROR shifted register.)
+    Register temp = AppropriateTempFor(rn);
+    Mov(temp, operand);
+    AddSubWithCarry(rd, rn, temp, S, op);
+  } else if (operand.IsShiftedRegister() && (operand.shift_amount() != 0)) {
+    // Add/sub with carry (shifted register).
+    ASSERT(operand.reg().SizeInBits() == rd.SizeInBits());
+    ASSERT(operand.shift() != ROR);
+    ASSERT(is_uintn(operand.shift_amount(),
+          rd.SizeInBits() == kXRegSize ? kXRegSizeLog2 : kWRegSizeLog2));
+    Register temp = AppropriateTempFor(rn, operand.reg());
+    EmitShift(temp, operand.reg(), operand.shift(), operand.shift_amount());
+    AddSubWithCarry(rd, rn, temp, S, op);
+
+  } else if (operand.IsExtendedRegister()) {
+    // Add/sub with carry (extended register).
+    ASSERT(operand.reg().SizeInBits() <= rd.SizeInBits());
+    // Add/sub extended supports a shift <= 4. We want to support exactly the
+    // same modes.
+    ASSERT(operand.shift_amount() <= 4);
+    ASSERT(operand.reg().Is64Bits() ||
+           ((operand.extend() != UXTX) && (operand.extend() != SXTX)));
+    Register temp = AppropriateTempFor(rn, operand.reg());
+    EmitExtendShift(temp, operand.reg(), operand.extend(),
+                    operand.shift_amount());
+    AddSubWithCarry(rd, rn, temp, S, op);
+
+  } else {
+    // The addressing mode is directly supported by the instruction.
+    AddSubWithCarry(rd, rn, operand, S, op);
+  }
+}
+
+
+void MacroAssembler::LoadStoreMacro(const CPURegister& rt,
+                                    const MemOperand& addr,
+                                    LoadStoreOp op) {
+  int64_t offset = addr.offset();
+  LSDataSize size = CalcLSDataSize(op);
+
+  // Check if an immediate offset fits in the immediate field of the
+  // appropriate instruction. If not, emit two instructions to perform
+  // the operation.
+  if (addr.IsImmediateOffset() && !IsImmLSScaled(offset, size) &&
+      !IsImmLSUnscaled(offset)) {
+    // Immediate offset that can't be encoded using unsigned or unscaled
+    // addressing modes.
+    Register temp = AppropriateTempFor(addr.base());
+    Mov(temp, addr.offset());
+    LoadStore(rt, MemOperand(addr.base(), temp), op);
+  } else if (addr.IsPostIndex() && !IsImmLSUnscaled(offset)) {
+    // Post-index beyond unscaled addressing range.
+    LoadStore(rt, MemOperand(addr.base()), op);
+    add(addr.base(), addr.base(), offset);
+  } else if (addr.IsPreIndex() && !IsImmLSUnscaled(offset)) {
+    // Pre-index beyond unscaled addressing range.
+    add(addr.base(), addr.base(), offset);
+    LoadStore(rt, MemOperand(addr.base()), op);
+  } else {
+    // Encodable in one load/store instruction.
+    LoadStore(rt, addr, op);
+  }
+}
+
+
+void MacroAssembler::Load(const Register& rt,
+                          const MemOperand& addr,
+                          Representation r) {
+  ASSERT(!r.IsDouble());
+
+  if (r.IsInteger8()) {
+    Ldrsb(rt, addr);
+  } else if (r.IsUInteger8()) {
+    Ldrb(rt, addr);
+  } else if (r.IsInteger16()) {
+    Ldrsh(rt, addr);
+  } else if (r.IsUInteger16()) {
+    Ldrh(rt, addr);
+  } else if (r.IsInteger32()) {
+    Ldr(rt.W(), addr);
+  } else {
+    ASSERT(rt.Is64Bits());
+    Ldr(rt, addr);
+  }
+}
+
+
+void MacroAssembler::Store(const Register& rt,
+                           const MemOperand& addr,
+                           Representation r) {
+  ASSERT(!r.IsDouble());
+
+  if (r.IsInteger8() || r.IsUInteger8()) {
+    Strb(rt, addr);
+  } else if (r.IsInteger16() || r.IsUInteger16()) {
+    Strh(rt, addr);
+  } else if (r.IsInteger32()) {
+    Str(rt.W(), addr);
+  } else {
+    ASSERT(rt.Is64Bits());
+    Str(rt, addr);
+  }
+}
+
+
+// Pseudo-instructions.
+
+
+void MacroAssembler::Abs(const Register& rd, const Register& rm,
+                         Label* is_not_representable,
+                         Label* is_representable) {
+  ASSERT(allow_macro_instructions_);
+  ASSERT(AreSameSizeAndType(rd, rm));
+
+  Cmp(rm, 1);
+  Cneg(rd, rm, lt);
+
+  // If the comparison sets the v flag, the input was the smallest value
+  // representable by rm, and the mathematical result of abs(rm) is not
+  // representable using two's complement.
+  if ((is_not_representable != NULL) && (is_representable != NULL)) {
+    B(is_not_representable, vs);
+    B(is_representable);
+  } else if (is_not_representable != NULL) {
+    B(is_not_representable, vs);
+  } else if (is_representable != NULL) {
+    B(is_representable, vc);
+  }
+}
+
+
+// Abstracted stack operations.
+
+
+void MacroAssembler::Push(const CPURegister& src0, const CPURegister& src1,
+                          const CPURegister& src2, const CPURegister& src3) {
+  ASSERT(AreSameSizeAndType(src0, src1, src2, src3));
+  ASSERT(src0.IsValid());
+
+  int count = 1 + src1.IsValid() + src2.IsValid() + src3.IsValid();
+  int size = src0.SizeInBytes();
+
+  PrepareForPush(count, size);
+  PushHelper(count, size, src0, src1, src2, src3);
+}
+
+
+void MacroAssembler::Pop(const CPURegister& dst0, const CPURegister& dst1,
+                         const CPURegister& dst2, const CPURegister& dst3) {
+  // It is not valid to pop into the same register more than once in one
+  // instruction, not even into the zero register.
+  ASSERT(!AreAliased(dst0, dst1, dst2, dst3));
+  ASSERT(AreSameSizeAndType(dst0, dst1, dst2, dst3));
+  ASSERT(dst0.IsValid());
+
+  int count = 1 + dst1.IsValid() + dst2.IsValid() + dst3.IsValid();
+  int size = dst0.SizeInBytes();
+
+  PrepareForPop(count, size);
+  PopHelper(count, size, dst0, dst1, dst2, dst3);
+
+  if (!csp.Is(StackPointer()) && emit_debug_code()) {
+    // It is safe to leave csp where it is when unwinding the JavaScript stack,
+    // but if we keep it matching StackPointer, the simulator can detect memory
+    // accesses in the now-free part of the stack.
+    Mov(csp, StackPointer());
+  }
+}
+
+
+void MacroAssembler::PushCPURegList(CPURegList registers) {
+  int size = registers.RegisterSizeInBytes();
+
+  PrepareForPush(registers.Count(), size);
+  // Push up to four registers at a time because if the current stack pointer is
+  // csp and reg_size is 32, registers must be pushed in blocks of four in order
+  // to maintain the 16-byte alignment for csp.
+  while (!registers.IsEmpty()) {
+    int count_before = registers.Count();
+    const CPURegister& src0 = registers.PopHighestIndex();
+    const CPURegister& src1 = registers.PopHighestIndex();
+    const CPURegister& src2 = registers.PopHighestIndex();
+    const CPURegister& src3 = registers.PopHighestIndex();
+    int count = count_before - registers.Count();
+    PushHelper(count, size, src0, src1, src2, src3);
+  }
+}
+
+
+void MacroAssembler::PopCPURegList(CPURegList registers) {
+  int size = registers.RegisterSizeInBytes();
+
+  PrepareForPop(registers.Count(), size);
+  // Pop up to four registers at a time because if the current stack pointer is
+  // csp and reg_size is 32, registers must be pushed in blocks of four in
+  // order to maintain the 16-byte alignment for csp.
+  while (!registers.IsEmpty()) {
+    int count_before = registers.Count();
+    const CPURegister& dst0 = registers.PopLowestIndex();
+    const CPURegister& dst1 = registers.PopLowestIndex();
+    const CPURegister& dst2 = registers.PopLowestIndex();
+    const CPURegister& dst3 = registers.PopLowestIndex();
+    int count = count_before - registers.Count();
+    PopHelper(count, size, dst0, dst1, dst2, dst3);
+  }
+
+  if (!csp.Is(StackPointer()) && emit_debug_code()) {
+    // It is safe to leave csp where it is when unwinding the JavaScript stack,
+    // but if we keep it matching StackPointer, the simulator can detect memory
+    // accesses in the now-free part of the stack.
+    Mov(csp, StackPointer());
+  }
+}
+
+
+void MacroAssembler::PushMultipleTimes(int count, Register src) {
+  int size = src.SizeInBytes();
+
+  PrepareForPush(count, size);
+
+  if (FLAG_optimize_for_size && count > 8) {
+    Label loop;
+    __ Mov(Tmp0(), count / 2);
+    __ Bind(&loop);
+    PushHelper(2, size, src, src, NoReg, NoReg);
+    __ Subs(Tmp0(), Tmp0(), 1);
+    __ B(ne, &loop);
+
+    count %= 2;
+  }
+
+  // Push up to four registers at a time if possible because if the current
+  // stack pointer is csp and the register size is 32, registers must be pushed
+  // in blocks of four in order to maintain the 16-byte alignment for csp.
+  while (count >= 4) {
+    PushHelper(4, size, src, src, src, src);
+    count -= 4;
+  }
+  if (count >= 2) {
+    PushHelper(2, size, src, src, NoReg, NoReg);
+    count -= 2;
+  }
+  if (count == 1) {
+    PushHelper(1, size, src, NoReg, NoReg, NoReg);
+    count -= 1;
+  }
+  ASSERT(count == 0);
+}
+
+
+void MacroAssembler::PushHelper(int count, int size,
+                                const CPURegister& src0,
+                                const CPURegister& src1,
+                                const CPURegister& src2,
+                                const CPURegister& src3) {
+  // Ensure that we don't unintentially modify scratch or debug registers.
+  InstructionAccurateScope scope(this);
+
+  ASSERT(AreSameSizeAndType(src0, src1, src2, src3));
+  ASSERT(size == src0.SizeInBytes());
+
+  // When pushing multiple registers, the store order is chosen such that
+  // Push(a, b) is equivalent to Push(a) followed by Push(b).
+  switch (count) {
+    case 1:
+      ASSERT(src1.IsNone() && src2.IsNone() && src3.IsNone());
+      str(src0, MemOperand(StackPointer(), -1 * size, PreIndex));
+      break;
+    case 2:
+      ASSERT(src2.IsNone() && src3.IsNone());
+      stp(src1, src0, MemOperand(StackPointer(), -2 * size, PreIndex));
+      break;
+    case 3:
+      ASSERT(src3.IsNone());
+      stp(src2, src1, MemOperand(StackPointer(), -3 * size, PreIndex));
+      str(src0, MemOperand(StackPointer(), 2 * size));
+      break;
+    case 4:
+      // Skip over 4 * size, then fill in the gap. This allows four W registers
+      // to be pushed using csp, whilst maintaining 16-byte alignment for csp
+      // at all times.
+      stp(src3, src2, MemOperand(StackPointer(), -4 * size, PreIndex));
+      stp(src1, src0, MemOperand(StackPointer(), 2 * size));
+      break;
+    default:
+      UNREACHABLE();
+  }
+}
+
+
+void MacroAssembler::PopHelper(int count, int size,
+                               const CPURegister& dst0,
+                               const CPURegister& dst1,
+                               const CPURegister& dst2,
+                               const CPURegister& dst3) {
+  // Ensure that we don't unintentially modify scratch or debug registers.
+  InstructionAccurateScope scope(this);
+
+  ASSERT(AreSameSizeAndType(dst0, dst1, dst2, dst3));
+  ASSERT(size == dst0.SizeInBytes());
+
+  // When popping multiple registers, the load order is chosen such that
+  // Pop(a, b) is equivalent to Pop(a) followed by Pop(b).
+  switch (count) {
+    case 1:
+      ASSERT(dst1.IsNone() && dst2.IsNone() && dst3.IsNone());
+      ldr(dst0, MemOperand(StackPointer(), 1 * size, PostIndex));
+      break;
+    case 2:
+      ASSERT(dst2.IsNone() && dst3.IsNone());
+      ldp(dst0, dst1, MemOperand(StackPointer(), 2 * size, PostIndex));
+      break;
+    case 3:
+      ASSERT(dst3.IsNone());
+      ldr(dst2, MemOperand(StackPointer(), 2 * size));
+      ldp(dst0, dst1, MemOperand(StackPointer(), 3 * size, PostIndex));
+      break;
+    case 4:
+      // Load the higher addresses first, then load the lower addresses and
+      // skip the whole block in the second instruction. This allows four W
+      // registers to be popped using csp, whilst maintaining 16-byte alignment
+      // for csp at all times.
+      ldp(dst2, dst3, MemOperand(StackPointer(), 2 * size));
+      ldp(dst0, dst1, MemOperand(StackPointer(), 4 * size, PostIndex));
+      break;
+    default:
+      UNREACHABLE();
+  }
+}
+
+
+void MacroAssembler::PrepareForPush(int count, int size) {
+  // TODO(jbramley): Use AssertStackConsistency here, if possible. See the
+  // AssertStackConsistency for details of why we can't at the moment.
+  if (csp.Is(StackPointer())) {
+    // If the current stack pointer is csp, then it must be aligned to 16 bytes
+    // on entry and the total size of the specified registers must also be a
+    // multiple of 16 bytes.
+    ASSERT((count * size) % 16 == 0);
+  } else {
+    // Even if the current stack pointer is not the system stack pointer (csp),
+    // the system stack pointer will still be modified in order to comply with
+    // ABI rules about accessing memory below the system stack pointer.
+    BumpSystemStackPointer(count * size);
+  }
+}
+
+
+void MacroAssembler::PrepareForPop(int count, int size) {
+  AssertStackConsistency();
+  if (csp.Is(StackPointer())) {
+    // If the current stack pointer is csp, then it must be aligned to 16 bytes
+    // on entry and the total size of the specified registers must also be a
+    // multiple of 16 bytes.
+    ASSERT((count * size) % 16 == 0);
+  }
+}
+
+
+void MacroAssembler::Poke(const CPURegister& src, const Operand& offset) {
+  if (offset.IsImmediate()) {
+    ASSERT(offset.immediate() >= 0);
+  } else if (emit_debug_code()) {
+    Cmp(xzr, offset);
+    Check(le, kStackAccessBelowStackPointer);
+  }
+
+  Str(src, MemOperand(StackPointer(), offset));
+}
+
+
+void MacroAssembler::Peek(const CPURegister& dst, const Operand& offset) {
+  if (offset.IsImmediate()) {
+    ASSERT(offset.immediate() >= 0);
+  } else if (emit_debug_code()) {
+    Cmp(xzr, offset);
+    Check(le, kStackAccessBelowStackPointer);
+  }
+
+  Ldr(dst, MemOperand(StackPointer(), offset));
+}
+
+
+void MacroAssembler::PokePair(const CPURegister& src1,
+                              const CPURegister& src2,
+                              int offset) {
+  ASSERT(AreSameSizeAndType(src1, src2));
+  ASSERT((offset >= 0) && ((offset % src1.SizeInBytes()) == 0));
+  Stp(src1, src2, MemOperand(StackPointer(), offset));
+}
+
+
+void MacroAssembler::PeekPair(const CPURegister& dst1,
+                              const CPURegister& dst2,
+                              int offset) {
+  ASSERT(AreSameSizeAndType(dst1, dst2));
+  ASSERT((offset >= 0) && ((offset % dst1.SizeInBytes()) == 0));
+  Ldp(dst1, dst2, MemOperand(StackPointer(), offset));
+}
+
+
+void MacroAssembler::PushCalleeSavedRegisters() {
+  // Ensure that the macro-assembler doesn't use any scratch registers.
+  InstructionAccurateScope scope(this);
+
+  // This method must not be called unless the current stack pointer is the
+  // system stack pointer (csp).
+  ASSERT(csp.Is(StackPointer()));
+
+  MemOperand tos(csp, -2 * kXRegSizeInBytes, PreIndex);
+
+  stp(d14, d15, tos);
+  stp(d12, d13, tos);
+  stp(d10, d11, tos);
+  stp(d8, d9, tos);
+
+  stp(x29, x30, tos);
+  stp(x27, x28, tos);    // x28 = jssp
+  stp(x25, x26, tos);
+  stp(x23, x24, tos);
+  stp(x21, x22, tos);
+  stp(x19, x20, tos);
+}
+
+
+void MacroAssembler::PopCalleeSavedRegisters() {
+  // Ensure that the macro-assembler doesn't use any scratch registers.
+  InstructionAccurateScope scope(this);
+
+  // This method must not be called unless the current stack pointer is the
+  // system stack pointer (csp).
+  ASSERT(csp.Is(StackPointer()));
+
+  MemOperand tos(csp, 2 * kXRegSizeInBytes, PostIndex);
+
+  ldp(x19, x20, tos);
+  ldp(x21, x22, tos);
+  ldp(x23, x24, tos);
+  ldp(x25, x26, tos);
+  ldp(x27, x28, tos);    // x28 = jssp
+  ldp(x29, x30, tos);
+
+  ldp(d8, d9, tos);
+  ldp(d10, d11, tos);
+  ldp(d12, d13, tos);
+  ldp(d14, d15, tos);
+}
+
+
+void MacroAssembler::AssertStackConsistency() {
+  if (emit_debug_code() && !csp.Is(StackPointer())) {
+    if (csp.Is(StackPointer())) {
+      // TODO(jbramley): Check for csp alignment if it is the stack pointer.
+    } else {
+      // TODO(jbramley): Currently we cannot use this assertion in Push because
+      // some calling code assumes that the flags are preserved. For an example,
+      // look at Builtins::Generate_ArgumentsAdaptorTrampoline.
+      Cmp(csp, StackPointer());
+      Check(ls, kTheCurrentStackPointerIsBelowCsp);
+    }
+  }
+}
+
+
+void MacroAssembler::LoadRoot(Register destination,
+                              Heap::RootListIndex index) {
+  // TODO(jbramley): Most root values are constants, and can be synthesized
+  // without a load. Refer to the ARM back end for details.
+  Ldr(destination, MemOperand(root, index << kPointerSizeLog2));
+}
+
+
+void MacroAssembler::StoreRoot(Register source,
+                               Heap::RootListIndex index) {
+  Str(source, MemOperand(root, index << kPointerSizeLog2));
+}
+
+
+void MacroAssembler::LoadTrueFalseRoots(Register true_root,
+                                        Register false_root) {
+  STATIC_ASSERT((Heap::kTrueValueRootIndex + 1) == Heap::kFalseValueRootIndex);
+  Ldp(true_root, false_root,
+      MemOperand(root, Heap::kTrueValueRootIndex << kPointerSizeLog2));
+}
+
+
+void MacroAssembler::LoadHeapObject(Register result,
+                                    Handle<HeapObject> object) {
+  AllowDeferredHandleDereference using_raw_address;
+  if (isolate()->heap()->InNewSpace(*object)) {
+    Handle<Cell> cell = isolate()->factory()->NewCell(object);
+    Mov(result, Operand(cell));
+    Ldr(result, FieldMemOperand(result, Cell::kValueOffset));
+  } else {
+    Mov(result, Operand(object));
+  }
+}
+
+
+void MacroAssembler::LoadInstanceDescriptors(Register map,
+                                             Register descriptors) {
+  Ldr(descriptors, FieldMemOperand(map, Map::kDescriptorsOffset));
+}
+
+
+void MacroAssembler::NumberOfOwnDescriptors(Register dst, Register map) {
+  Ldr(dst, FieldMemOperand(map, Map::kBitField3Offset));
+  DecodeField<Map::NumberOfOwnDescriptorsBits>(dst);
+}
+
+
+void MacroAssembler::EnumLengthUntagged(Register dst, Register map) {
+  STATIC_ASSERT(Map::EnumLengthBits::kShift == 0);
+  Ldrsw(dst, UntagSmiFieldMemOperand(map, Map::kBitField3Offset));
+  And(dst, dst, Map::EnumLengthBits::kMask);
+}
+
+
+void MacroAssembler::EnumLengthSmi(Register dst, Register map) {
+  STATIC_ASSERT(Map::EnumLengthBits::kShift == 0);
+  Ldr(dst, FieldMemOperand(map, Map::kBitField3Offset));
+  And(dst, dst, Operand(Smi::FromInt(Map::EnumLengthBits::kMask)));
+}
+
+
+void MacroAssembler::CheckEnumCache(Register object,
+                                    Register null_value,
+                                    Register scratch0,
+                                    Register scratch1,
+                                    Register scratch2,
+                                    Register scratch3,
+                                    Label* call_runtime) {
+  ASSERT(!AreAliased(object, null_value, scratch0, scratch1, scratch2,
+                     scratch3));
+
+  Register empty_fixed_array_value = scratch0;
+  Register current_object = scratch1;
+
+  LoadRoot(empty_fixed_array_value, Heap::kEmptyFixedArrayRootIndex);
+  Label next, start;
+
+  Mov(current_object, object);
+
+  // Check if the enum length field is properly initialized, indicating that
+  // there is an enum cache.
+  Register map = scratch2;
+  Register enum_length = scratch3;
+  Ldr(map, FieldMemOperand(current_object, HeapObject::kMapOffset));
+
+  EnumLengthUntagged(enum_length, map);
+  Cmp(enum_length, kInvalidEnumCacheSentinel);
+  B(eq, call_runtime);
+
+  B(&start);
+
+  Bind(&next);
+  Ldr(map, FieldMemOperand(current_object, HeapObject::kMapOffset));
+
+  // For all objects but the receiver, check that the cache is empty.
+  EnumLengthUntagged(enum_length, map);
+  Cbnz(enum_length, call_runtime);
+
+  Bind(&start);
+
+  // Check that there are no elements. Register current_object contains the
+  // current JS object we've reached through the prototype chain.
+  Label no_elements;
+  Ldr(current_object, FieldMemOperand(current_object,
+                                      JSObject::kElementsOffset));
+  Cmp(current_object, empty_fixed_array_value);
+  B(eq, &no_elements);
+
+  // Second chance, the object may be using the empty slow element dictionary.
+  CompareRoot(current_object, Heap::kEmptySlowElementDictionaryRootIndex);
+  B(ne, call_runtime);
+
+  Bind(&no_elements);
+  Ldr(current_object, FieldMemOperand(map, Map::kPrototypeOffset));
+  Cmp(current_object, null_value);
+  B(ne, &next);
+}
+
+
+void MacroAssembler::TestJSArrayForAllocationMemento(Register receiver,
+                                                     Register scratch1,
+                                                     Register scratch2,
+                                                     Label* no_memento_found) {
+  ExternalReference new_space_start =
+      ExternalReference::new_space_start(isolate());
+  ExternalReference new_space_allocation_top =
+      ExternalReference::new_space_allocation_top_address(isolate());
+
+  Add(scratch1, receiver,
+      JSArray::kSize + AllocationMemento::kSize - kHeapObjectTag);
+  Cmp(scratch1, Operand(new_space_start));
+  B(lt, no_memento_found);
+
+  Mov(scratch2, Operand(new_space_allocation_top));
+  Ldr(scratch2, MemOperand(scratch2));
+  Cmp(scratch1, scratch2);
+  B(gt, no_memento_found);
+
+  Ldr(scratch1, MemOperand(scratch1, -AllocationMemento::kSize));
+  Cmp(scratch1,
+      Operand(isolate()->factory()->allocation_memento_map()));
+}
+
+
+void MacroAssembler::JumpToHandlerEntry(Register exception,
+                                        Register object,
+                                        Register state,
+                                        Register scratch1,
+                                        Register scratch2) {
+  // Handler expects argument in x0.
+  ASSERT(exception.Is(x0));
+
+  // Compute the handler entry address and jump to it. The handler table is
+  // a fixed array of (smi-tagged) code offsets.
+  Ldr(scratch1, FieldMemOperand(object, Code::kHandlerTableOffset));
+  Add(scratch1, scratch1, FixedArray::kHeaderSize - kHeapObjectTag);
+  STATIC_ASSERT(StackHandler::kKindWidth < kPointerSizeLog2);
+  Lsr(scratch2, state, StackHandler::kKindWidth);
+  Ldr(scratch2, MemOperand(scratch1, scratch2, LSL, kPointerSizeLog2));
+  Add(scratch1, object, Code::kHeaderSize - kHeapObjectTag);
+  Add(scratch1, scratch1, Operand::UntagSmi(scratch2));
+  Br(scratch1);
+}
+
+
+void MacroAssembler::InNewSpace(Register object,
+                                Condition cond,
+                                Label* branch) {
+  ASSERT(cond == eq || cond == ne);
+  // Use Tmp1() to have a different destination register, as Tmp0() will be used
+  // for relocation.
+  And(Tmp1(), object, Operand(ExternalReference::new_space_mask(isolate())));
+  Cmp(Tmp1(), Operand(ExternalReference::new_space_start(isolate())));
+  B(cond, branch);
+}
+
+
+void MacroAssembler::Throw(Register value,
+                           Register scratch1,
+                           Register scratch2,
+                           Register scratch3,
+                           Register scratch4) {
+  // Adjust this code if not the case.
+  STATIC_ASSERT(StackHandlerConstants::kSize == 5 * kPointerSize);
+  STATIC_ASSERT(StackHandlerConstants::kNextOffset == 0);
+  STATIC_ASSERT(StackHandlerConstants::kCodeOffset == 1 * kPointerSize);
+  STATIC_ASSERT(StackHandlerConstants::kStateOffset == 2 * kPointerSize);
+  STATIC_ASSERT(StackHandlerConstants::kContextOffset == 3 * kPointerSize);
+  STATIC_ASSERT(StackHandlerConstants::kFPOffset == 4 * kPointerSize);
+
+  // The handler expects the exception in x0.
+  ASSERT(value.Is(x0));
+
+  // Drop the stack pointer to the top of the top handler.
+  ASSERT(jssp.Is(StackPointer()));
+  Mov(scratch1, Operand(ExternalReference(Isolate::kHandlerAddress,
+                                          isolate())));
+  Ldr(jssp, MemOperand(scratch1));
+  // Restore the next handler.
+  Pop(scratch2);
+  Str(scratch2, MemOperand(scratch1));
+
+  // Get the code object and state.  Restore the context and frame pointer.
+  Register object = scratch1;
+  Register state = scratch2;
+  Pop(object, state, cp, fp);
+
+  // If the handler is a JS frame, restore the context to the frame.
+  // (kind == ENTRY) == (fp == 0) == (cp == 0), so we could test either fp
+  // or cp.
+  Label not_js_frame;
+  Cbz(cp, &not_js_frame);
+  Str(cp, MemOperand(fp, StandardFrameConstants::kContextOffset));
+  Bind(&not_js_frame);
+
+  JumpToHandlerEntry(value, object, state, scratch3, scratch4);
+}
+
+
+void MacroAssembler::ThrowUncatchable(Register value,
+                                      Register scratch1,
+                                      Register scratch2,
+                                      Register scratch3,
+                                      Register scratch4) {
+  // Adjust this code if not the case.
+  STATIC_ASSERT(StackHandlerConstants::kSize == 5 * kPointerSize);
+  STATIC_ASSERT(StackHandlerConstants::kNextOffset == 0 * kPointerSize);
+  STATIC_ASSERT(StackHandlerConstants::kCodeOffset == 1 * kPointerSize);
+  STATIC_ASSERT(StackHandlerConstants::kStateOffset == 2 * kPointerSize);
+  STATIC_ASSERT(StackHandlerConstants::kContextOffset == 3 * kPointerSize);
+  STATIC_ASSERT(StackHandlerConstants::kFPOffset == 4 * kPointerSize);
+
+  // The handler expects the exception in x0.
+  ASSERT(value.Is(x0));
+
+  // Drop the stack pointer to the top of the top stack handler.
+  ASSERT(jssp.Is(StackPointer()));
+  Mov(scratch1, Operand(ExternalReference(Isolate::kHandlerAddress,
+                                          isolate())));
+  Ldr(jssp, MemOperand(scratch1));
+
+  // Unwind the handlers until the ENTRY handler is found.
+  Label fetch_next, check_kind;
+  B(&check_kind);
+  Bind(&fetch_next);
+  Peek(jssp, StackHandlerConstants::kNextOffset);
+
+  Bind(&check_kind);
+  STATIC_ASSERT(StackHandler::JS_ENTRY == 0);
+  Peek(scratch2, StackHandlerConstants::kStateOffset);
+  TestAndBranchIfAnySet(scratch2, StackHandler::KindField::kMask, &fetch_next);
+
+  // Set the top handler address to next handler past the top ENTRY handler.
+  Pop(scratch2);
+  Str(scratch2, MemOperand(scratch1));
+
+  // Get the code object and state.  Clear the context and frame pointer (0 was
+  // saved in the handler).
+  Register object = scratch1;
+  Register state = scratch2;
+  Pop(object, state, cp, fp);
+
+  JumpToHandlerEntry(value, object, state, scratch3, scratch4);
+}
+
+
+void MacroAssembler::Throw(BailoutReason reason) {
+  Label throw_start;
+  Bind(&throw_start);
+#ifdef DEBUG
+  const char* msg = GetBailoutReason(reason);
+  RecordComment("Throw message: ");
+  RecordComment((msg != NULL) ? msg : "UNKNOWN");
+#endif
+
+  Mov(x0, Operand(Smi::FromInt(reason)));
+  Push(x0);
+
+  // Disable stub call restrictions to always allow calls to throw.
+  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);
+    CallRuntime(Runtime::kThrowMessage, 1);
+  } else {
+    CallRuntime(Runtime::kThrowMessage, 1);
+  }
+  // ThrowMessage should not return here.
+  Unreachable();
+}
+
+
+void MacroAssembler::ThrowIf(Condition cc, BailoutReason reason) {
+  Label ok;
+  B(InvertCondition(cc), &ok);
+  Throw(reason);
+  Bind(&ok);
+}
+
+
+void MacroAssembler::ThrowIfSmi(const Register& value, BailoutReason reason) {
+  Label ok;
+  JumpIfNotSmi(value, &ok);
+  Throw(reason);
+  Bind(&ok);
+}
+
+
+void MacroAssembler::SmiAbs(const Register& smi, Label* slow) {
+  ASSERT(smi.Is64Bits());
+  Abs(smi, smi, slow);
+}
+
+
+void MacroAssembler::AssertSmi(Register object, BailoutReason reason) {
+  if (emit_debug_code()) {
+    STATIC_ASSERT(kSmiTag == 0);
+    Tst(object, kSmiTagMask);
+    Check(eq, reason);
+  }
+}
+
+
+void MacroAssembler::AssertNotSmi(Register object, BailoutReason reason) {
+  if (emit_debug_code()) {
+    STATIC_ASSERT(kSmiTag == 0);
+    Tst(object, kSmiTagMask);
+    Check(ne, reason);
+  }
+}
+
+
+void MacroAssembler::AssertName(Register object) {
+  if (emit_debug_code()) {
+    STATIC_ASSERT(kSmiTag == 0);
+    // TODO(jbramley): Add AbortIfSmi and related functions.
+    Label not_smi;
+    JumpIfNotSmi(object, &not_smi);
+    Abort(kOperandIsASmiAndNotAName);
+    Bind(&not_smi);
+
+    Ldr(Tmp1(), FieldMemOperand(object, HeapObject::kMapOffset));
+    CompareInstanceType(Tmp1(), Tmp1(), LAST_NAME_TYPE);
+    Check(ls, kOperandIsNotAName);
+  }
+}
+
+
+void MacroAssembler::AssertString(Register object) {
+  if (emit_debug_code()) {
+    Register temp = Tmp1();
+    STATIC_ASSERT(kSmiTag == 0);
+    Tst(object, kSmiTagMask);
+    Check(ne, kOperandIsASmiAndNotAString);
+    Ldr(temp, FieldMemOperand(object, HeapObject::kMapOffset));
+    CompareInstanceType(temp, temp, FIRST_NONSTRING_TYPE);
+    Check(lo, kOperandIsNotAString);
+  }
+}
+
+
+void MacroAssembler::CallStub(CodeStub* stub, TypeFeedbackId ast_id) {
+  ASSERT(AllowThisStubCall(stub));  // Stub calls are not allowed in some stubs.
+  Call(stub->GetCode(isolate()), RelocInfo::CODE_TARGET, ast_id);
+}
+
+
+void MacroAssembler::TailCallStub(CodeStub* stub) {
+  Jump(stub->GetCode(isolate()), RelocInfo::CODE_TARGET);
+}
+
+
+void MacroAssembler::CallRuntime(const Runtime::Function* f,
+                                 int num_arguments,
+                                 SaveFPRegsMode save_doubles) {
+  // All arguments must be on the stack before this function is called.
+  // x0 holds the return value after the call.
+
+  // Check that the number of arguments matches what the function expects.
+  // If f->nargs is -1, the function can accept a variable number of arguments.
+  if (f->nargs >= 0 && f->nargs != num_arguments) {
+    // Illegal operation: drop the stack arguments and return undefined.
+    if (num_arguments > 0) {
+      Drop(num_arguments);
+    }
+    LoadRoot(x0, Heap::kUndefinedValueRootIndex);
+    return;
+  }
+
+  // Place the necessary arguments.
+  Mov(x0, num_arguments);
+  Mov(x1, Operand(ExternalReference(f, isolate())));
+
+  CEntryStub stub(1, save_doubles);
+  CallStub(&stub);
+}
+
+
+static int AddressOffset(ExternalReference ref0, ExternalReference ref1) {
+  return ref0.address() - ref1.address();
+}
+
+
+void MacroAssembler::CallApiFunctionAndReturn(
+    Register function_address,
+    ExternalReference thunk_ref,
+    int stack_space,
+    int spill_offset,
+    MemOperand return_value_operand,
+    MemOperand* context_restore_operand) {
+  ASM_LOCATION("CallApiFunctionAndReturn");
+  ExternalReference next_address =
+      ExternalReference::handle_scope_next_address(isolate());
+  const int kNextOffset = 0;
+  const int kLimitOffset = AddressOffset(
+      ExternalReference::handle_scope_limit_address(isolate()),
+      next_address);
+  const int kLevelOffset = AddressOffset(
+      ExternalReference::handle_scope_level_address(isolate()),
+      next_address);
+
+  ASSERT(function_address.is(x1) || function_address.is(x2));
+
+  Label profiler_disabled;
+  Label end_profiler_check;
+  bool* is_profiling_flag = isolate()->cpu_profiler()->is_profiling_address();
+  STATIC_ASSERT(sizeof(*is_profiling_flag) == 1);
+  Mov(x10, reinterpret_cast<uintptr_t>(is_profiling_flag));
+  Ldrb(w10, MemOperand(x10));
+  Cbz(w10, &profiler_disabled);
+  Mov(x3, Operand(thunk_ref));
+  B(&end_profiler_check);
+
+  Bind(&profiler_disabled);
+  Mov(x3, function_address);
+  Bind(&end_profiler_check);
+
+  // Save the callee-save registers we are going to use.
+  // TODO(all): Is this necessary? ARM doesn't do it.
+  STATIC_ASSERT(kCallApiFunctionSpillSpace == 4);
+  Poke(x19, (spill_offset + 0) * kXRegSizeInBytes);
+  Poke(x20, (spill_offset + 1) * kXRegSizeInBytes);
+  Poke(x21, (spill_offset + 2) * kXRegSizeInBytes);
+  Poke(x22, (spill_offset + 3) * kXRegSizeInBytes);
+
+  // Allocate HandleScope in callee-save registers.
+  // We will need to restore the HandleScope after the call to the API function,
+  // by allocating it in callee-save registers they will be preserved by C code.
+  Register handle_scope_base = x22;
+  Register next_address_reg = x19;
+  Register limit_reg = x20;
+  Register level_reg = w21;
+
+  Mov(handle_scope_base, Operand(next_address));
+  Ldr(next_address_reg, MemOperand(handle_scope_base, kNextOffset));
+  Ldr(limit_reg, MemOperand(handle_scope_base, kLimitOffset));
+  Ldr(level_reg, MemOperand(handle_scope_base, kLevelOffset));
+  Add(level_reg, level_reg, 1);
+  Str(level_reg, MemOperand(handle_scope_base, kLevelOffset));
+
+  if (FLAG_log_timer_events) {
+    FrameScope frame(this, StackFrame::MANUAL);
+    PushSafepointRegisters();
+    Mov(x0, Operand(ExternalReference::isolate_address(isolate())));
+    CallCFunction(ExternalReference::log_enter_external_function(isolate()), 1);
+    PopSafepointRegisters();
+  }
+
+  // Native call returns to the DirectCEntry stub which redirects to the
+  // return address pushed on stack (could have moved after GC).
+  // DirectCEntry stub itself is generated early and never moves.
+  DirectCEntryStub stub;
+  stub.GenerateCall(this, x3);
+
+  if (FLAG_log_timer_events) {
+    FrameScope frame(this, StackFrame::MANUAL);
+    PushSafepointRegisters();
+    Mov(x0, Operand(ExternalReference::isolate_address(isolate())));
+    CallCFunction(ExternalReference::log_leave_external_function(isolate()), 1);
+    PopSafepointRegisters();
+  }
+
+  Label promote_scheduled_exception;
+  Label exception_handled;
+  Label delete_allocated_handles;
+  Label leave_exit_frame;
+  Label return_value_loaded;
+
+  // Load value from ReturnValue.
+  Ldr(x0, return_value_operand);
+  Bind(&return_value_loaded);
+  // No more valid handles (the result handle was the last one). Restore
+  // previous handle scope.
+  Str(next_address_reg, MemOperand(handle_scope_base, kNextOffset));
+  if (emit_debug_code()) {
+    Ldr(w1, MemOperand(handle_scope_base, kLevelOffset));
+    Cmp(w1, level_reg);
+    Check(eq, kUnexpectedLevelAfterReturnFromApiCall);
+  }
+  Sub(level_reg, level_reg, 1);
+  Str(level_reg, MemOperand(handle_scope_base, kLevelOffset));
+  Ldr(x1, MemOperand(handle_scope_base, kLimitOffset));
+  Cmp(limit_reg, x1);
+  B(ne, &delete_allocated_handles);
+
+  Bind(&leave_exit_frame);
+  // Restore callee-saved registers.
+  Peek(x19, (spill_offset + 0) * kXRegSizeInBytes);
+  Peek(x20, (spill_offset + 1) * kXRegSizeInBytes);
+  Peek(x21, (spill_offset + 2) * kXRegSizeInBytes);
+  Peek(x22, (spill_offset + 3) * kXRegSizeInBytes);
+
+  // Check if the function scheduled an exception.
+  Mov(x5, Operand(ExternalReference::scheduled_exception_address(isolate())));
+  Ldr(x5, MemOperand(x5));
+  JumpIfNotRoot(x5, Heap::kTheHoleValueRootIndex, &promote_scheduled_exception);
+  Bind(&exception_handled);
+
+  bool restore_context = context_restore_operand != NULL;
+  if (restore_context) {
+    Ldr(cp, *context_restore_operand);
+  }
+
+  LeaveExitFrame(false, x1, !restore_context);
+  Drop(stack_space);
+  Ret();
+
+  Bind(&promote_scheduled_exception);
+  {
+    FrameScope frame(this, StackFrame::INTERNAL);
+    CallExternalReference(
+        ExternalReference(Runtime::kPromoteScheduledException, isolate()), 0);
+  }
+  B(&exception_handled);
+
+  // HandleScope limit has changed. Delete allocated extensions.
+  Bind(&delete_allocated_handles);
+  Str(limit_reg, MemOperand(handle_scope_base, kLimitOffset));
+  // Save the return value in a callee-save register.
+  Register saved_result = x19;
+  Mov(saved_result, x0);
+  Mov(x0, Operand(ExternalReference::isolate_address(isolate())));
+  CallCFunction(
+      ExternalReference::delete_handle_scope_extensions(isolate()), 1);
+  Mov(x0, saved_result);
+  B(&leave_exit_frame);
+}
+
+
+void MacroAssembler::CallExternalReference(const ExternalReference& ext,
+                                           int num_arguments) {
+  Mov(x0, num_arguments);
+  Mov(x1, Operand(ext));
+
+  CEntryStub stub(1);
+  CallStub(&stub);
+}
+
+
+void MacroAssembler::JumpToExternalReference(const ExternalReference& builtin) {
+  Mov(x1, Operand(builtin));
+  CEntryStub stub(1);
+  Jump(stub.GetCode(isolate()), RelocInfo::CODE_TARGET);
+}
+
+
+void MacroAssembler::GetBuiltinFunction(Register target,
+                                        Builtins::JavaScript id) {
+  // Load the builtins object into target register.
+  Ldr(target, GlobalObjectMemOperand());
+  Ldr(target, FieldMemOperand(target, GlobalObject::kBuiltinsOffset));
+  // Load the JavaScript builtin function from the builtins object.
+  Ldr(target, FieldMemOperand(target,
+                          JSBuiltinsObject::OffsetOfFunctionWithId(id)));
+}
+
+
+void MacroAssembler::GetBuiltinEntry(Register target, Builtins::JavaScript id) {
+  ASSERT(!target.is(x1));
+  GetBuiltinFunction(x1, id);
+  // Load the code entry point from the builtins object.
+  Ldr(target, FieldMemOperand(x1, JSFunction::kCodeEntryOffset));
+}
+
+
+void MacroAssembler::InvokeBuiltin(Builtins::JavaScript id,
+                                   InvokeFlag flag,
+                                   const CallWrapper& call_wrapper) {
+  ASM_LOCATION("MacroAssembler::InvokeBuiltin");
+  // You can't call a builtin without a valid frame.
+  ASSERT(flag == JUMP_FUNCTION || has_frame());
+
+  GetBuiltinEntry(x2, id);
+  if (flag == CALL_FUNCTION) {
+    call_wrapper.BeforeCall(CallSize(x2));
+    Call(x2);
+    call_wrapper.AfterCall();
+  } else {
+    ASSERT(flag == JUMP_FUNCTION);
+    Jump(x2);
+  }
+}
+
+
+void MacroAssembler::TailCallExternalReference(const ExternalReference& ext,
+                                               int num_arguments,
+                                               int result_size) {
+  // 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.
+  Mov(x0, num_arguments);
+  JumpToExternalReference(ext);
+}
+
+
+void MacroAssembler::TailCallRuntime(Runtime::FunctionId fid,
+                                     int num_arguments,
+                                     int result_size) {
+  TailCallExternalReference(ExternalReference(fid, isolate()),
+                            num_arguments,
+                            result_size);
+}
+
+
+void MacroAssembler::InitializeNewString(Register string,
+                                         Register length,
+                                         Heap::RootListIndex map_index,
+                                         Register scratch1,
+                                         Register scratch2) {
+  ASSERT(!AreAliased(string, length, scratch1, scratch2));
+  LoadRoot(scratch2, map_index);
+  SmiTag(scratch1, length);
+  Str(scratch2, FieldMemOperand(string, HeapObject::kMapOffset));
+
+  Mov(scratch2, String::kEmptyHashField);
+  Str(scratch1, FieldMemOperand(string, String::kLengthOffset));
+  Str(scratch2, FieldMemOperand(string, String::kHashFieldOffset));
+}
+
+
+int MacroAssembler::ActivationFrameAlignment() {
+#if V8_HOST_ARCH_A64
+  // Running on the real platform. Use the alignment as mandated by the local
+  // environment.
+  // Note: This will break if we ever start generating snapshots on one ARM
+  // platform for another ARM platform with a different alignment.
+  return OS::ActivationFrameAlignment();
+#else  // V8_HOST_ARCH_A64
+  // If we are using the simulator then we should always align to the expected
+  // alignment. As the simulator is used to generate snapshots we do not know
+  // if the target platform will need alignment, so this is controlled from a
+  // flag.
+  return FLAG_sim_stack_alignment;
+#endif  // V8_HOST_ARCH_A64
+}
+
+
+void MacroAssembler::CallCFunction(ExternalReference function,
+                                   int num_of_reg_args) {
+  CallCFunction(function, num_of_reg_args, 0);
+}
+
+
+void MacroAssembler::CallCFunction(ExternalReference function,
+                                   int num_of_reg_args,
+                                   int num_of_double_args) {
+  Mov(Tmp0(), Operand(function));
+  CallCFunction(Tmp0(), num_of_reg_args, num_of_double_args);
+}
+
+
+void MacroAssembler::CallCFunction(Register function,
+                                   int num_of_reg_args,
+                                   int num_of_double_args) {
+  ASSERT(has_frame());
+  // We can pass 8 integer arguments in registers. If we need to pass more than
+  // that, we'll need to implement support for passing them on the stack.
+  ASSERT(num_of_reg_args <= 8);
+
+  // If we're passing doubles, we're limited to the following prototypes
+  // (defined by ExternalReference::Type):
+  //  BUILTIN_COMPARE_CALL:  int f(double, double)
+  //  BUILTIN_FP_FP_CALL:    double f(double, double)
+  //  BUILTIN_FP_CALL:       double f(double)
+  //  BUILTIN_FP_INT_CALL:   double f(double, int)
+  if (num_of_double_args > 0) {
+    ASSERT(num_of_reg_args <= 1);
+    ASSERT((num_of_double_args + num_of_reg_args) <= 2);
+  }
+
+
+  // If the stack pointer is not csp, we need to derive an aligned csp from the
+  // current stack pointer.
+  const Register old_stack_pointer = StackPointer();
+  if (!csp.Is(old_stack_pointer)) {
+    AssertStackConsistency();
+
+    int sp_alignment = ActivationFrameAlignment();
+    // The ABI mandates at least 16-byte alignment.
+    ASSERT(sp_alignment >= 16);
+    ASSERT(IsPowerOf2(sp_alignment));
+
+    // The current stack pointer is a callee saved register, and is preserved
+    // across the call.
+    ASSERT(kCalleeSaved.IncludesAliasOf(old_stack_pointer));
+
+    // Align and synchronize the system stack pointer with jssp.
+    Bic(csp, old_stack_pointer, sp_alignment - 1);
+    SetStackPointer(csp);
+  }
+
+  // Call directly. The function called cannot cause a GC, or allow preemption,
+  // so the return address in the link register stays correct.
+  Call(function);
+
+  if (!csp.Is(old_stack_pointer)) {
+    if (emit_debug_code()) {
+      // Because the stack pointer must be aligned on a 16-byte boundary, the
+      // aligned csp can be up to 12 bytes below the jssp. This is the case
+      // where we only pushed one W register on top of an aligned jssp.
+      Register temp = Tmp1();
+      ASSERT(ActivationFrameAlignment() == 16);
+      Sub(temp, csp, old_stack_pointer);
+      // We want temp <= 0 && temp >= -12.
+      Cmp(temp, 0);
+      Ccmp(temp, -12, NFlag, le);
+      Check(ge, kTheStackWasCorruptedByMacroAssemblerCall);
+    }
+    SetStackPointer(old_stack_pointer);
+  }
+}
+
+
+void MacroAssembler::Jump(Register target) {
+  Br(target);
+}
+
+
+void MacroAssembler::Jump(intptr_t target, RelocInfo::Mode rmode) {
+  Mov(Tmp0(), Operand(target, rmode));
+  Br(Tmp0());
+}
+
+
+void MacroAssembler::Jump(Address target, RelocInfo::Mode rmode) {
+  ASSERT(!RelocInfo::IsCodeTarget(rmode));
+  Jump(reinterpret_cast<intptr_t>(target), rmode);
+}
+
+
+void MacroAssembler::Jump(Handle<Code> code, RelocInfo::Mode rmode) {
+  ASSERT(RelocInfo::IsCodeTarget(rmode));
+  AllowDeferredHandleDereference embedding_raw_address;
+  Jump(reinterpret_cast<intptr_t>(code.location()), rmode);
+}
+
+
+void MacroAssembler::Call(Register target) {
+  BlockConstPoolScope scope(this);
+#ifdef DEBUG
+  Label start_call;
+  Bind(&start_call);
+#endif
+
+  Blr(target);
+
+#ifdef DEBUG
+  AssertSizeOfCodeGeneratedSince(&start_call, CallSize(target));
+#endif
+}
+
+
+void MacroAssembler::Call(Label* target) {
+  BlockConstPoolScope scope(this);
+#ifdef DEBUG
+  Label start_call;
+  Bind(&start_call);
+#endif
+
+  Bl(target);
+
+#ifdef DEBUG
+  AssertSizeOfCodeGeneratedSince(&start_call, CallSize(target));
+#endif
+}
+
+
+// MacroAssembler::CallSize is sensitive to changes in this function, as it
+// requires to know how many instructions are used to branch to the target.
+void MacroAssembler::Call(Address target, RelocInfo::Mode rmode) {
+  BlockConstPoolScope scope(this);
+#ifdef DEBUG
+  Label start_call;
+  Bind(&start_call);
+#endif
+  // Statement positions are expected to be recorded when the target
+  // address is loaded.
+  positions_recorder()->WriteRecordedPositions();
+
+  // Addresses always have 64 bits, so we shouldn't encounter NONE32.
+  ASSERT(rmode != RelocInfo::NONE32);
+
+  if (rmode == RelocInfo::NONE64) {
+    uint64_t imm = reinterpret_cast<uint64_t>(target);
+    movz(Tmp0(), (imm >> 0) & 0xffff, 0);
+    movk(Tmp0(), (imm >> 16) & 0xffff, 16);
+    movk(Tmp0(), (imm >> 32) & 0xffff, 32);
+    movk(Tmp0(), (imm >> 48) & 0xffff, 48);
+  } else {
+    LoadRelocated(Tmp0(), Operand(reinterpret_cast<intptr_t>(target), rmode));
+  }
+  Blr(Tmp0());
+#ifdef DEBUG
+  AssertSizeOfCodeGeneratedSince(&start_call, CallSize(target, rmode));
+#endif
+}
+
+
+void MacroAssembler::Call(Handle<Code> code,
+                          RelocInfo::Mode rmode,
+                          TypeFeedbackId ast_id) {
+#ifdef DEBUG
+  Label start_call;
+  Bind(&start_call);
+#endif
+
+  if ((rmode == RelocInfo::CODE_TARGET) && (!ast_id.IsNone())) {
+    SetRecordedAstId(ast_id);
+    rmode = RelocInfo::CODE_TARGET_WITH_ID;
+  }
+
+  AllowDeferredHandleDereference embedding_raw_address;
+  Call(reinterpret_cast<Address>(code.location()), rmode);
+
+#ifdef DEBUG
+  // Check the size of the code generated.
+  AssertSizeOfCodeGeneratedSince(&start_call, CallSize(code, rmode, ast_id));
+#endif
+}
+
+
+int MacroAssembler::CallSize(Register target) {
+  USE(target);
+  return kInstructionSize;
+}
+
+
+int MacroAssembler::CallSize(Label* target) {
+  USE(target);
+  return kInstructionSize;
+}
+
+
+int MacroAssembler::CallSize(Address target, RelocInfo::Mode rmode) {
+  USE(target);
+
+  // Addresses always have 64 bits, so we shouldn't encounter NONE32.
+  ASSERT(rmode != RelocInfo::NONE32);
+
+  if (rmode == RelocInfo::NONE64) {
+    return kCallSizeWithoutRelocation;
+  } else {
+    return kCallSizeWithRelocation;
+  }
+}
+
+
+int MacroAssembler::CallSize(Handle<Code> code,
+                             RelocInfo::Mode rmode,
+                             TypeFeedbackId ast_id) {
+  USE(code);
+  USE(ast_id);
+
+  // Addresses always have 64 bits, so we shouldn't encounter NONE32.
+  ASSERT(rmode != RelocInfo::NONE32);
+
+  if (rmode == RelocInfo::NONE64) {
+    return kCallSizeWithoutRelocation;
+  } else {
+    return kCallSizeWithRelocation;
+  }
+}
+
+
+
+
+
+void MacroAssembler::JumpForHeapNumber(Register object,
+                                       Register heap_number_map,
+                                       Label* on_heap_number,
+                                       Label* on_not_heap_number) {
+  ASSERT(on_heap_number || on_not_heap_number);
+  // Tmp0() is used as a scratch register.
+  ASSERT(!AreAliased(Tmp0(), heap_number_map));
+  AssertNotSmi(object);
+
+  // Load the HeapNumber map if it is not passed.
+  if (heap_number_map.Is(NoReg)) {
+    heap_number_map = Tmp1();
+    LoadRoot(heap_number_map, Heap::kHeapNumberMapRootIndex);
+  } else {
+    // This assert clobbers Tmp0(), so do it before loading Tmp0() with the map.
+    AssertRegisterIsRoot(heap_number_map, Heap::kHeapNumberMapRootIndex);
+  }
+
+  Ldr(Tmp0(), FieldMemOperand(object, HeapObject::kMapOffset));
+  Cmp(Tmp0(), heap_number_map);
+
+  if (on_heap_number) {
+    B(eq, on_heap_number);
+  }
+  if (on_not_heap_number) {
+    B(ne, on_not_heap_number);
+  }
+}
+
+
+void MacroAssembler::JumpIfHeapNumber(Register object,
+                                      Label* on_heap_number,
+                                      Register heap_number_map) {
+  JumpForHeapNumber(object,
+                    heap_number_map,
+                    on_heap_number,
+                    NULL);
+}
+
+
+void MacroAssembler::JumpIfNotHeapNumber(Register object,
+                                         Label* on_not_heap_number,
+                                         Register heap_number_map) {
+  JumpForHeapNumber(object,
+                    heap_number_map,
+                    NULL,
+                    on_not_heap_number);
+}
+
+
+void MacroAssembler::LookupNumberStringCache(Register object,
+                                             Register result,
+                                             Register scratch1,
+                                             Register scratch2,
+                                             Register scratch3,
+                                             Label* not_found) {
+  ASSERT(!AreAliased(object, result, scratch1, scratch2, scratch3));
+
+  // Use of registers. Register result is used as a temporary.
+  Register number_string_cache = result;
+  Register mask = scratch3;
+
+  // Load the number string cache.
+  LoadRoot(number_string_cache, Heap::kNumberStringCacheRootIndex);
+
+  // Make the hash mask from the length of the number string cache. It
+  // contains two elements (number and string) for each cache entry.
+  Ldrsw(mask, UntagSmiFieldMemOperand(number_string_cache,
+                                      FixedArray::kLengthOffset));
+  Asr(mask, mask, 1);  // Divide length by two.
+  Sub(mask, mask, 1);  // Make mask.
+
+  // Calculate the entry in the number string cache. The hash value in the
+  // number string cache for smis is just the smi value, and the hash for
+  // doubles is the xor of the upper and lower words. See
+  // Heap::GetNumberStringCache.
+  Label is_smi;
+  Label load_result_from_cache;
+
+  JumpIfSmi(object, &is_smi);
+  CheckMap(object, scratch1, Heap::kHeapNumberMapRootIndex, not_found,
+           DONT_DO_SMI_CHECK);
+
+  STATIC_ASSERT(kDoubleSize == (kWRegSizeInBytes * 2));
+  Add(scratch1, object, HeapNumber::kValueOffset - kHeapObjectTag);
+  Ldp(scratch1.W(), scratch2.W(), MemOperand(scratch1));
+  Eor(scratch1, scratch1, scratch2);
+  And(scratch1, scratch1, mask);
+
+  // Calculate address of entry in string cache: each entry consists of two
+  // pointer sized fields.
+  Add(scratch1, number_string_cache,
+      Operand(scratch1, LSL, kPointerSizeLog2 + 1));
+
+  Register probe = mask;
+  Ldr(probe, FieldMemOperand(scratch1, FixedArray::kHeaderSize));
+  JumpIfSmi(probe, not_found);
+  Ldr(d0, FieldMemOperand(object, HeapNumber::kValueOffset));
+  Ldr(d1, FieldMemOperand(probe, HeapNumber::kValueOffset));
+  Fcmp(d0, d1);
+  B(ne, not_found);
+  B(&load_result_from_cache);
+
+  Bind(&is_smi);
+  Register scratch = scratch1;
+  And(scratch, mask, Operand::UntagSmi(object));
+  // Calculate address of entry in string cache: each entry consists
+  // of two pointer sized fields.
+  Add(scratch, number_string_cache,
+      Operand(scratch, LSL, kPointerSizeLog2 + 1));
+
+  // Check if the entry is the smi we are looking for.
+  Ldr(probe, FieldMemOperand(scratch, FixedArray::kHeaderSize));
+  Cmp(object, probe);
+  B(ne, not_found);
+
+  // Get the result from the cache.
+  Bind(&load_result_from_cache);
+  Ldr(result, FieldMemOperand(scratch, FixedArray::kHeaderSize + kPointerSize));
+  IncrementCounter(isolate()->counters()->number_to_string_native(), 1,
+                   scratch1, scratch2);
+}
+
+
+void MacroAssembler::TryConvertDoubleToInt(Register as_int,
+                                           FPRegister value,
+                                           FPRegister scratch_d,
+                                           Label* on_successful_conversion,
+                                           Label* on_failed_conversion) {
+  // Convert to an int and back again, then compare with the original value.
+  Fcvtzs(as_int, value);
+  Scvtf(scratch_d, as_int);
+  Fcmp(value, scratch_d);
+
+  if (on_successful_conversion) {
+    B(on_successful_conversion, eq);
+  }
+  if (on_failed_conversion) {
+    B(on_failed_conversion, ne);
+  }
+}
+
+
+void MacroAssembler::JumpIfMinusZero(DoubleRegister input,
+                                     Label* on_negative_zero) {
+  // Floating point -0.0 is kMinInt as an integer, so subtracting 1 (cmp) will
+  // cause overflow.
+  Fmov(Tmp0(), input);
+  Cmp(Tmp0(), 1);
+  B(vs, on_negative_zero);
+}
+
+
+void MacroAssembler::ClampInt32ToUint8(Register output, Register input) {
+  // Clamp the value to [0..255].
+  Cmp(input.W(), Operand(input.W(), UXTB));
+  // If input < input & 0xff, it must be < 0, so saturate to 0.
+  Csel(output.W(), wzr, input.W(), lt);
+  // Create a constant 0xff.
+  Mov(WTmp0(), 255);
+  // If input > input & 0xff, it must be > 255, so saturate to 255.
+  Csel(output.W(), WTmp0(), output.W(), gt);
+}
+
+
+void MacroAssembler::ClampInt32ToUint8(Register in_out) {
+  ClampInt32ToUint8(in_out, in_out);
+}
+
+
+void MacroAssembler::ClampDoubleToUint8(Register output,
+                                        DoubleRegister input,
+                                        DoubleRegister dbl_scratch) {
+  // This conversion follows the WebIDL "[Clamp]" rules for PIXEL types:
+  //   - Inputs lower than 0 (including -infinity) produce 0.
+  //   - Inputs higher than 255 (including +infinity) produce 255.
+  // Also, it seems that PIXEL types use round-to-nearest rather than
+  // round-towards-zero.
+
+  // Squash +infinity before the conversion, since Fcvtnu will normally
+  // convert it to 0.
+  Fmov(dbl_scratch, 255);
+  Fmin(dbl_scratch, dbl_scratch, input);
+
+  // Convert double to unsigned integer. Values less than zero become zero.
+  // Values greater than 255 have already been clamped to 255.
+  Fcvtnu(output, dbl_scratch);
+}
+
+
+void MacroAssembler::CopyFieldsLoopPairsHelper(Register dst,
+                                               Register src,
+                                               unsigned count,
+                                               Register scratch1,
+                                               Register scratch2,
+                                               Register scratch3) {
+  // Untag src and dst into scratch registers.
+  // Copy src->dst in a tight loop.
+  ASSERT(!AreAliased(dst, src, scratch1, scratch2, scratch3, Tmp0(), Tmp1()));
+  ASSERT(count >= 2);
+
+  const Register& remaining = scratch3;
+  Mov(remaining, count / 2);
+
+  // Only use the Assembler, so we can use Tmp0() and Tmp1().
+  InstructionAccurateScope scope(this);
+
+  const Register& dst_untagged = scratch1;
+  const Register& src_untagged = scratch2;
+  sub(dst_untagged, dst, kHeapObjectTag);
+  sub(src_untagged, src, kHeapObjectTag);
+
+  // Copy fields in pairs.
+  Label loop;
+  bind(&loop);
+  ldp(Tmp0(), Tmp1(), MemOperand(src_untagged, kXRegSizeInBytes * 2,
+                                 PostIndex));
+  stp(Tmp0(), Tmp1(), MemOperand(dst_untagged, kXRegSizeInBytes * 2,
+                                 PostIndex));
+  sub(remaining, remaining, 1);
+  cbnz(remaining, &loop);
+
+  // Handle the leftovers.
+  if (count & 1) {
+    ldr(Tmp0(), MemOperand(src_untagged));
+    str(Tmp0(), MemOperand(dst_untagged));
+  }
+}
+
+
+void MacroAssembler::CopyFieldsUnrolledPairsHelper(Register dst,
+                                                   Register src,
+                                                   unsigned count,
+                                                   Register scratch1,
+                                                   Register scratch2) {
+  // Untag src and dst into scratch registers.
+  // Copy src->dst in an unrolled loop.
+  ASSERT(!AreAliased(dst, src, scratch1, scratch2, Tmp0(), Tmp1()));
+
+  // Only use the Assembler, so we can use Tmp0() and Tmp1().
+  InstructionAccurateScope scope(this);
+
+  const Register& dst_untagged = scratch1;
+  const Register& src_untagged = scratch2;
+  sub(dst_untagged, dst, kHeapObjectTag);
+  sub(src_untagged, src, kHeapObjectTag);
+
+  // Copy fields in pairs.
+  for (unsigned i = 0; i < count / 2; i++) {
+    ldp(Tmp0(), Tmp1(), MemOperand(src_untagged, kXRegSizeInBytes * 2,
+                                   PostIndex));
+    stp(Tmp0(), Tmp1(), MemOperand(dst_untagged, kXRegSizeInBytes * 2,
+                                   PostIndex));
+  }
+
+  // Handle the leftovers.
+  if (count & 1) {
+    ldr(Tmp0(), MemOperand(src_untagged));
+    str(Tmp0(), MemOperand(dst_untagged));
+  }
+}
+
+
+void MacroAssembler::CopyFieldsUnrolledHelper(Register dst,
+                                              Register src,
+                                              unsigned count,
+                                              Register scratch1) {
+  // Untag src and dst into scratch registers.
+  // Copy src->dst in an unrolled loop.
+  ASSERT(!AreAliased(dst, src, scratch1, Tmp0(), Tmp1()));
+
+  // Only use the Assembler, so we can use Tmp0() and Tmp1().
+  InstructionAccurateScope scope(this);
+
+  const Register& dst_untagged = scratch1;
+  const Register& src_untagged = Tmp1();
+  sub(dst_untagged, dst, kHeapObjectTag);
+  sub(src_untagged, src, kHeapObjectTag);
+
+  // Copy fields one by one.
+  for (unsigned i = 0; i < count; i++) {
+    ldr(Tmp0(), MemOperand(src_untagged, kXRegSizeInBytes, PostIndex));
+    str(Tmp0(), MemOperand(dst_untagged, kXRegSizeInBytes, PostIndex));
+  }
+}
+
+
+void MacroAssembler::CopyFields(Register dst, Register src, CPURegList temps,
+                                unsigned count) {
+  // One of two methods is used:
+  //
+  // For high 'count' values where many scratch registers are available:
+  //    Untag src and dst into scratch registers.
+  //    Copy src->dst in a tight loop.
+  //
+  // For low 'count' values or where few scratch registers are available:
+  //    Untag src and dst into scratch registers.
+  //    Copy src->dst in an unrolled loop.
+  //
+  // In both cases, fields are copied in pairs if possible, and left-overs are
+  // handled separately.
+  ASSERT(!temps.IncludesAliasOf(dst));
+  ASSERT(!temps.IncludesAliasOf(src));
+  ASSERT(!temps.IncludesAliasOf(Tmp0()));
+  ASSERT(!temps.IncludesAliasOf(Tmp1()));
+  ASSERT(!temps.IncludesAliasOf(xzr));
+  ASSERT(!AreAliased(dst, src, Tmp0(), Tmp1()));
+
+  if (emit_debug_code()) {
+    Cmp(dst, src);
+    Check(ne, kTheSourceAndDestinationAreTheSame);
+  }
+
+  // The value of 'count' at which a loop will be generated (if there are
+  // enough scratch registers).
+  static const unsigned kLoopThreshold = 8;
+
+  ASSERT(!temps.IsEmpty());
+  Register scratch1 = Register(temps.PopLowestIndex());
+  Register scratch2 = Register(temps.PopLowestIndex());
+  Register scratch3 = Register(temps.PopLowestIndex());
+
+  if (scratch3.IsValid() && (count >= kLoopThreshold)) {
+    CopyFieldsLoopPairsHelper(dst, src, count, scratch1, scratch2, scratch3);
+  } else if (scratch2.IsValid()) {
+    CopyFieldsUnrolledPairsHelper(dst, src, count, scratch1, scratch2);
+  } else if (scratch1.IsValid()) {
+    CopyFieldsUnrolledHelper(dst, src, count, scratch1);
+  } else {
+    UNREACHABLE();
+  }
+}
+
+
+void MacroAssembler::CopyBytes(Register dst,
+                               Register src,
+                               Register length,
+                               Register scratch,
+                               CopyHint hint) {
+  ASSERT(!AreAliased(src, dst, length, scratch));
+
+  // TODO(all): Implement a faster copy function, and use hint to determine
+  // which algorithm to use for copies.
+  if (emit_debug_code()) {
+    // Check copy length.
+    Cmp(length, 0);
+    Assert(ge, kUnexpectedNegativeValue);
+
+    // Check src and dst buffers don't overlap.
+    Add(scratch, src, length);  // Calculate end of src buffer.
+    Cmp(scratch, dst);
+    Add(scratch, dst, length);  // Calculate end of dst buffer.
+    Ccmp(scratch, src, ZFlag, gt);
+    Assert(le, kCopyBuffersOverlap);
+  }
+
+  Label loop, done;
+  Cbz(length, &done);
+
+  Bind(&loop);
+  Sub(length, length, 1);
+  Ldrb(scratch, MemOperand(src, 1, PostIndex));
+  Strb(scratch, MemOperand(dst, 1, PostIndex));
+  Cbnz(length, &loop);
+  Bind(&done);
+}
+
+
+void MacroAssembler::InitializeFieldsWithFiller(Register start_offset,
+                                                Register end_offset,
+                                                Register filler) {
+  Label loop, entry;
+  B(&entry);
+  Bind(&loop);
+  // TODO(all): consider using stp here.
+  Str(filler, MemOperand(start_offset, kPointerSize, PostIndex));
+  Bind(&entry);
+  Cmp(start_offset, end_offset);
+  B(lt, &loop);
+}
+
+
+void MacroAssembler::JumpIfEitherIsNotSequentialAsciiStrings(
+    Register first,
+    Register second,
+    Register scratch1,
+    Register scratch2,
+    Label* failure,
+    SmiCheckType smi_check) {
+
+  if (smi_check == DO_SMI_CHECK) {
+    JumpIfEitherSmi(first, second, failure);
+  } else if (emit_debug_code()) {
+    ASSERT(smi_check == DONT_DO_SMI_CHECK);
+    Label not_smi;
+    JumpIfEitherSmi(first, second, NULL, &not_smi);
+
+    // At least one input is a smi, but the flags indicated a smi check wasn't
+    // needed.
+    Abort(kUnexpectedSmi);
+
+    Bind(&not_smi);
+  }
+
+  // Test that both first and second are sequential ASCII strings.
+  Ldr(scratch1, FieldMemOperand(first, HeapObject::kMapOffset));
+  Ldr(scratch2, FieldMemOperand(second, HeapObject::kMapOffset));
+  Ldrb(scratch1, FieldMemOperand(scratch1, Map::kInstanceTypeOffset));
+  Ldrb(scratch2, FieldMemOperand(scratch2, Map::kInstanceTypeOffset));
+
+  JumpIfEitherInstanceTypeIsNotSequentialAscii(scratch1,
+                                               scratch2,
+                                               scratch1,
+                                               scratch2,
+                                               failure);
+}
+
+
+void MacroAssembler::JumpIfEitherInstanceTypeIsNotSequentialAscii(
+    Register first,
+    Register second,
+    Register scratch1,
+    Register scratch2,
+    Label* failure) {
+  ASSERT(!AreAliased(scratch1, second));
+  ASSERT(!AreAliased(scratch1, scratch2));
+  static const int kFlatAsciiStringMask =
+      kIsNotStringMask | kStringEncodingMask | kStringRepresentationMask;
+  static const int kFlatAsciiStringTag = ASCII_STRING_TYPE;
+  And(scratch1, first, kFlatAsciiStringMask);
+  And(scratch2, second, kFlatAsciiStringMask);
+  Cmp(scratch1, kFlatAsciiStringTag);
+  Ccmp(scratch2, kFlatAsciiStringTag, NoFlag, eq);
+  B(ne, failure);
+}
+
+
+void MacroAssembler::JumpIfInstanceTypeIsNotSequentialAscii(Register type,
+                                                            Register scratch,
+                                                            Label* failure) {
+  const int kFlatAsciiStringMask =
+      kIsNotStringMask | kStringEncodingMask | kStringRepresentationMask;
+  const int kFlatAsciiStringTag =
+      kStringTag | kOneByteStringTag | kSeqStringTag;
+  And(scratch, type, kFlatAsciiStringMask);
+  Cmp(scratch, kFlatAsciiStringTag);
+  B(ne, failure);
+}
+
+
+void MacroAssembler::JumpIfBothInstanceTypesAreNotSequentialAscii(
+    Register first,
+    Register second,
+    Register scratch1,
+    Register scratch2,
+    Label* failure) {
+  ASSERT(!AreAliased(first, second, scratch1, scratch2));
+  const int kFlatAsciiStringMask =
+      kIsNotStringMask | kStringEncodingMask | kStringRepresentationMask;
+  const int kFlatAsciiStringTag =
+      kStringTag | kOneByteStringTag | kSeqStringTag;
+  And(scratch1, first, kFlatAsciiStringMask);
+  And(scratch2, second, kFlatAsciiStringMask);
+  Cmp(scratch1, kFlatAsciiStringTag);
+  Ccmp(scratch2, kFlatAsciiStringTag, NoFlag, eq);
+  B(ne, failure);
+}
+
+
+void MacroAssembler::JumpIfNotUniqueName(Register type,
+                                         Label* not_unique_name) {
+  STATIC_ASSERT((kInternalizedTag == 0) && (kStringTag == 0));
+  // if ((type is string && type is internalized) || type == SYMBOL_TYPE) {
+  //   continue
+  // } else {
+  //   goto not_unique_name
+  // }
+  Tst(type, kIsNotStringMask | kIsNotInternalizedMask);
+  Ccmp(type, SYMBOL_TYPE, ZFlag, ne);
+  B(ne, not_unique_name);
+}
+
+
+void MacroAssembler::InvokePrologue(const ParameterCount& expected,
+                                    const ParameterCount& actual,
+                                    Handle<Code> code_constant,
+                                    Register code_reg,
+                                    Label* done,
+                                    InvokeFlag flag,
+                                    bool* definitely_mismatches,
+                                    const CallWrapper& call_wrapper) {
+  bool definitely_matches = false;
+  *definitely_mismatches = false;
+  Label regular_invoke;
+
+  // Check whether the expected and actual arguments count match. If not,
+  // setup registers according to contract with ArgumentsAdaptorTrampoline:
+  //  x0: actual arguments count.
+  //  x1: function (passed through to callee).
+  //  x2: expected arguments count.
+
+  // The code below is made a lot easier because the calling code already sets
+  // up actual and expected registers according to the contract if values are
+  // passed in registers.
+  ASSERT(actual.is_immediate() || actual.reg().is(x0));
+  ASSERT(expected.is_immediate() || expected.reg().is(x2));
+  ASSERT((!code_constant.is_null() && code_reg.is(no_reg)) || code_reg.is(x3));
+
+  if (expected.is_immediate()) {
+    ASSERT(actual.is_immediate());
+    if (expected.immediate() == actual.immediate()) {
+      definitely_matches = true;
+
+    } else {
+      Mov(x0, actual.immediate());
+      if (expected.immediate() ==
+          SharedFunctionInfo::kDontAdaptArgumentsSentinel) {
+        // Don't worry about adapting arguments for builtins 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 up x2 for the argument adaptor.
+        Mov(x2, expected.immediate());
+      }
+    }
+
+  } else {  // expected is a register.
+    Operand actual_op = actual.is_immediate() ? Operand(actual.immediate())
+                                              : Operand(actual.reg());
+    // If actual == expected perform a regular invocation.
+    Cmp(expected.reg(), actual_op);
+    B(eq, &regular_invoke);
+    // Otherwise set up x0 for the argument adaptor.
+    Mov(x0, actual_op);
+  }
+
+  // If the argument counts may mismatch, generate a call to the argument
+  // adaptor.
+  if (!definitely_matches) {
+    if (!code_constant.is_null()) {
+      Mov(x3, Operand(code_constant));
+      Add(x3, x3, Code::kHeaderSize - kHeapObjectTag);
+    }
+
+    Handle<Code> adaptor =
+        isolate()->builtins()->ArgumentsAdaptorTrampoline();
+    if (flag == CALL_FUNCTION) {
+      call_wrapper.BeforeCall(CallSize(adaptor));
+      Call(adaptor);
+      call_wrapper.AfterCall();
+      if (!*definitely_mismatches) {
+        // If the arg counts don't match, no extra code is emitted by
+        // MAsm::InvokeCode and we can just fall through.
+        B(done);
+      }
+    } else {
+      Jump(adaptor, RelocInfo::CODE_TARGET);
+    }
+  }
+  Bind(&regular_invoke);
+}
+
+
+void MacroAssembler::InvokeCode(Register code,
+                                const ParameterCount& expected,
+                                const ParameterCount& actual,
+                                InvokeFlag flag,
+                                const CallWrapper& call_wrapper) {
+  // You can't call a function without a valid frame.
+  ASSERT(flag == JUMP_FUNCTION || has_frame());
+
+  Label done;
+
+  bool definitely_mismatches = false;
+  InvokePrologue(expected, actual, Handle<Code>::null(), code, &done, flag,
+                 &definitely_mismatches, call_wrapper);
+
+  // If we are certain that actual != expected, then we know InvokePrologue will
+  // have handled the call through the argument adaptor mechanism.
+  // The called function expects the call kind in x5.
+  if (!definitely_mismatches) {
+    if (flag == CALL_FUNCTION) {
+      call_wrapper.BeforeCall(CallSize(code));
+      Call(code);
+      call_wrapper.AfterCall();
+    } else {
+      ASSERT(flag == JUMP_FUNCTION);
+      Jump(code);
+    }
+  }
+
+  // Continue here if InvokePrologue does handle the invocation due to
+  // mismatched parameter counts.
+  Bind(&done);
+}
+
+
+void MacroAssembler::InvokeFunction(Register function,
+                                    const ParameterCount& actual,
+                                    InvokeFlag flag,
+                                    const CallWrapper& call_wrapper) {
+  // You can't call a function without a valid frame.
+  ASSERT(flag == JUMP_FUNCTION || has_frame());
+
+  // Contract with called JS functions requires that function is passed in x1.
+  // (See FullCodeGenerator::Generate().)
+  ASSERT(function.is(x1));
+
+  Register expected_reg = x2;
+  Register code_reg = x3;
+
+  Ldr(cp, FieldMemOperand(function, JSFunction::kContextOffset));
+  // The number of arguments is stored as an int32_t, and -1 is a marker
+  // (SharedFunctionInfo::kDontAdaptArgumentsSentinel), so we need sign
+  // extension to correctly handle it.
+  Ldr(expected_reg, FieldMemOperand(function,
+                                    JSFunction::kSharedFunctionInfoOffset));
+  Ldrsw(expected_reg,
+        FieldMemOperand(expected_reg,
+                        SharedFunctionInfo::kFormalParameterCountOffset));
+  Ldr(code_reg,
+      FieldMemOperand(function, JSFunction::kCodeEntryOffset));
+
+  ParameterCount expected(expected_reg);
+  InvokeCode(code_reg, expected, actual, flag, call_wrapper);
+}
+
+
+void MacroAssembler::InvokeFunction(Register function,
+                                    const ParameterCount& expected,
+                                    const ParameterCount& actual,
+                                    InvokeFlag flag,
+                                    const CallWrapper& call_wrapper) {
+  // You can't call a function without a valid frame.
+  ASSERT(flag == JUMP_FUNCTION || has_frame());
+
+  // Contract with called JS functions requires that function is passed in x1.
+  // (See FullCodeGenerator::Generate().)
+  ASSERT(function.Is(x1));
+
+  Register code_reg = x3;
+
+  // Set up the context.
+  Ldr(cp, FieldMemOperand(function, JSFunction::kContextOffset));
+
+  // We call indirectly through the code field in the function to
+  // allow recompilation to take effect without changing any of the
+  // call sites.
+  Ldr(code_reg, FieldMemOperand(function, JSFunction::kCodeEntryOffset));
+  InvokeCode(code_reg, expected, actual, flag, call_wrapper);
+}
+
+
+void MacroAssembler::InvokeFunction(Handle<JSFunction> function,
+                                    const ParameterCount& expected,
+                                    const ParameterCount& actual,
+                                    InvokeFlag flag,
+                                    const CallWrapper& call_wrapper) {
+  // Contract with called JS functions requires that function is passed in x1.
+  // (See FullCodeGenerator::Generate().)
+  __ LoadObject(x1, function);
+  InvokeFunction(x1, expected, actual, flag, call_wrapper);
+}
+
+
+void MacroAssembler::ECMA262ToInt32(Register result,
+                                    DoubleRegister input,
+                                    Register scratch1,
+                                    Register scratch2,
+                                    ECMA262ToInt32Result format) {
+  ASSERT(!AreAliased(result, scratch1, scratch2));
+  ASSERT(result.Is64Bits() && scratch1.Is64Bits() && scratch2.Is64Bits());
+  STATIC_ASSERT(kSmiTag == 0);
+  STATIC_ASSERT(kSmiValueSize == 32);
+
+  Label done, tag, manual_conversion;
+
+  // 1. Try to convert with a FPU convert instruction. It's trivial to compute
+  //    the modulo operation on an integer register so we convert to a 64-bit
+  //    integer, then find the 32-bit result from that.
+  //
+  // Fcvtzs will saturate to INT64_MIN (0x800...00) or INT64_MAX (0x7ff...ff)
+  // when the double is out of range. NaNs and infinities will be converted to 0
+  // (as ECMA-262 requires).
+  Fcvtzs(result, input);
+
+  // The values INT64_MIN (0x800...00) or INT64_MAX (0x7ff...ff) are not
+  // representable using a double, so if the result is one of those then we know
+  // that saturation occured, and we need to manually handle the conversion.
+  //
+  // It is easy to detect INT64_MIN and INT64_MAX because adding or subtracting
+  // 1 will cause signed overflow.
+  Cmp(result, 1);
+  Ccmp(result, -1, VFlag, vc);
+  B(vc, &tag);
+
+  // 2. Manually convert the input to an int32.
+  Fmov(result, input);
+
+  // Extract the exponent.
+  Register exponent = scratch1;
+  Ubfx(exponent, result, HeapNumber::kMantissaBits, HeapNumber::kExponentBits);
+
+  // It the exponent is >= 84 (kMantissaBits + 32), the result is always 0 since
+  // the mantissa gets shifted completely out of the int32_t result.
+  Cmp(exponent, HeapNumber::kExponentBias + HeapNumber::kMantissaBits + 32);
+  CzeroX(result, ge);
+  B(ge, &done);
+
+  // The Fcvtzs sequence handles all cases except where the conversion causes
+  // signed overflow in the int64_t target. Since we've already handled
+  // exponents >= 84, we can guarantee that 63 <= exponent < 84.
+
+  if (emit_debug_code()) {
+    Cmp(exponent, HeapNumber::kExponentBias + 63);
+    // Exponents less than this should have been handled by the Fcvt case.
+    Check(ge, kUnexpectedValue);
+  }
+
+  // Isolate the mantissa bits, and set the implicit '1'.
+  Register mantissa = scratch2;
+  Ubfx(mantissa, result, 0, HeapNumber::kMantissaBits);
+  Orr(mantissa, mantissa, 1UL << HeapNumber::kMantissaBits);
+
+  // Negate the mantissa if necessary.
+  Tst(result, kXSignMask);
+  Cneg(mantissa, mantissa, ne);
+
+  // Shift the mantissa bits in the correct place. We know that we have to shift
+  // it left here, because exponent >= 63 >= kMantissaBits.
+  Sub(exponent, exponent,
+      HeapNumber::kExponentBias + HeapNumber::kMantissaBits);
+  Lsl(result, mantissa, exponent);
+
+  Bind(&tag);
+  switch (format) {
+    case INT32_IN_W:
+      // There is nothing to do; the upper 32 bits are undefined.
+      if (emit_debug_code()) {
+        __ Mov(scratch1, 0x55555555);
+        __ Bfi(result, scratch1, 32, 32);
+      }
+      break;
+    case INT32_IN_X:
+      Sxtw(result, result);
+      break;
+    case SMI:
+      SmiTag(result);
+      break;
+  }
+
+  Bind(&done);
+}
+
+
+void MacroAssembler::HeapNumberECMA262ToInt32(Register result,
+                                              Register heap_number,
+                                              Register scratch1,
+                                              Register scratch2,
+                                              DoubleRegister double_scratch,
+                                              ECMA262ToInt32Result format) {
+  if (emit_debug_code()) {
+    // Verify we indeed have a HeapNumber.
+    Label ok;
+    JumpIfHeapNumber(heap_number, &ok);
+    Abort(kExpectedHeapNumber);
+    Bind(&ok);
+  }
+
+  Ldr(double_scratch, FieldMemOperand(heap_number, HeapNumber::kValueOffset));
+  ECMA262ToInt32(result, double_scratch, scratch1, scratch2, format);
+}
+
+
+void MacroAssembler::Prologue(PrologueFrameMode frame_mode) {
+  if (frame_mode == BUILD_STUB_FRAME) {
+    ASSERT(StackPointer().Is(jssp));
+    // TODO(jbramley): Does x1 contain a JSFunction here, or does it already
+    // have the special STUB smi?
+    __ Mov(Tmp0(), Operand(Smi::FromInt(StackFrame::STUB)));
+    // Compiled stubs don't age, and so they don't need the predictable code
+    // ageing sequence.
+    __ Push(lr, fp, cp, Tmp0());
+    __ Add(fp, jssp, StandardFrameConstants::kFixedFrameSizeFromFp);
+  } else {
+    if (isolate()->IsCodePreAgingActive()) {
+      Code* stub = Code::GetPreAgedCodeAgeStub(isolate());
+      __ EmitCodeAgeSequence(stub);
+    } else {
+      __ EmitFrameSetupForCodeAgePatching();
+    }
+  }
+}
+
+
+void MacroAssembler::EnterFrame(StackFrame::Type type) {
+  ASSERT(jssp.Is(StackPointer()));
+  Push(lr, fp, cp);
+  Mov(Tmp1(), Operand(Smi::FromInt(type)));
+  Mov(Tmp0(), Operand(CodeObject()));
+  Push(Tmp1(), Tmp0());
+  // jssp[4] : lr
+  // jssp[3] : fp
+  // jssp[2] : cp
+  // jssp[1] : type
+  // jssp[0] : code object
+
+  // Adjust FP to point to saved FP.
+  add(fp, jssp, StandardFrameConstants::kFixedFrameSizeFromFp + kPointerSize);
+}
+
+
+void MacroAssembler::LeaveFrame(StackFrame::Type type) {
+  ASSERT(jssp.Is(StackPointer()));
+  // Drop the execution stack down to the frame pointer and restore
+  // the caller frame pointer and return address.
+  Mov(jssp, fp);
+  AssertStackConsistency();
+  Pop(fp, lr);
+}
+
+
+void MacroAssembler::ExitFramePreserveFPRegs() {
+  PushCPURegList(kCallerSavedFP);
+}
+
+
+void MacroAssembler::ExitFrameRestoreFPRegs() {
+  // Read the registers from the stack without popping them. The stack pointer
+  // will be reset as part of the unwinding process.
+  CPURegList saved_fp_regs = kCallerSavedFP;
+  ASSERT(saved_fp_regs.Count() % 2 == 0);
+
+  int offset = ExitFrameConstants::kLastExitFrameField;
+  while (!saved_fp_regs.IsEmpty()) {
+    const CPURegister& dst0 = saved_fp_regs.PopHighestIndex();
+    const CPURegister& dst1 = saved_fp_regs.PopHighestIndex();
+    offset -= 2 * kDRegSizeInBytes;
+    Ldp(dst1, dst0, MemOperand(fp, offset));
+  }
+}
+
+
+// TODO(jbramley): Check that we're handling the frame pointer correctly.
+void MacroAssembler::EnterExitFrame(bool save_doubles,
+                                    const Register& scratch,
+                                    int extra_space) {
+  ASSERT(jssp.Is(StackPointer()));
+
+  // Set up the new stack frame.
+  Mov(scratch, Operand(CodeObject()));
+  Push(lr, fp);
+  Mov(fp, StackPointer());
+  Push(xzr, scratch);
+  //          fp[8]: CallerPC (lr)
+  //    fp -> fp[0]: CallerFP (old fp)
+  //          fp[-8]: Space reserved for SPOffset.
+  //  jssp -> fp[-16]: CodeObject()
+  STATIC_ASSERT((2 * kPointerSize) ==
+                ExitFrameConstants::kCallerSPDisplacement);
+  STATIC_ASSERT((1 * kPointerSize) == ExitFrameConstants::kCallerPCOffset);
+  STATIC_ASSERT((0 * kPointerSize) == ExitFrameConstants::kCallerFPOffset);
+  STATIC_ASSERT((-1 * kPointerSize) == ExitFrameConstants::kSPOffset);
+  STATIC_ASSERT((-2 * kPointerSize) == ExitFrameConstants::kCodeOffset);
+
+  // Save the frame pointer and context pointer in the top frame.
+  Mov(scratch, Operand(ExternalReference(Isolate::kCEntryFPAddress,
+                                         isolate())));
+  Str(fp, MemOperand(scratch));
+  Mov(scratch, Operand(ExternalReference(Isolate::kContextAddress,
+                                         isolate())));
+  Str(cp, MemOperand(scratch));
+
+  STATIC_ASSERT((-2 * kPointerSize) ==
+                ExitFrameConstants::kLastExitFrameField);
+  if (save_doubles) {
+    ExitFramePreserveFPRegs();
+  }
+
+  // Reserve space for the return address and for user requested memory.
+  // We do this before aligning to make sure that we end up correctly
+  // aligned with the minimum of wasted space.
+  Claim(extra_space + 1, kXRegSizeInBytes);
+  //         fp[8]: CallerPC (lr)
+  //   fp -> fp[0]: CallerFP (old fp)
+  //         fp[-8]: Space reserved for SPOffset.
+  //         fp[-16]: CodeObject()
+  //         jssp[-16 - fp_size]: Saved doubles (if save_doubles is true).
+  //         jssp[8]: Extra space reserved for caller (if extra_space != 0).
+  // jssp -> jssp[0]: Space reserved for the return address.
+
+  // Align and synchronize the system stack pointer with jssp.
+  AlignAndSetCSPForFrame();
+  ASSERT(csp.Is(StackPointer()));
+
+  //         fp[8]: CallerPC (lr)
+  //   fp -> fp[0]: CallerFP (old fp)
+  //         fp[-8]: Space reserved for SPOffset.
+  //         fp[-16]: CodeObject()
+  //         csp[...]: Saved doubles, if saved_doubles is true.
+  //         csp[8]: Memory reserved for the caller if extra_space != 0.
+  //                 Alignment padding, if necessary.
+  //  csp -> csp[0]: Space reserved for the return address.
+
+  // ExitFrame::GetStateForFramePointer expects to find the return address at
+  // the memory address immediately below the pointer stored in SPOffset.
+  // It is not safe to derive much else from SPOffset, because the size of the
+  // padding can vary.
+  Add(scratch, csp, kXRegSizeInBytes);
+  Str(scratch, MemOperand(fp, ExitFrameConstants::kSPOffset));
+}
+
+
+// Leave the current exit frame.
+void MacroAssembler::LeaveExitFrame(bool restore_doubles,
+                                    const Register& scratch,
+                                    bool restore_context) {
+  ASSERT(csp.Is(StackPointer()));
+
+  if (restore_doubles) {
+    ExitFrameRestoreFPRegs();
+  }
+
+  // Restore the context pointer from the top frame.
+  if (restore_context) {
+    Mov(scratch, Operand(ExternalReference(Isolate::kContextAddress,
+                                           isolate())));
+    Ldr(cp, MemOperand(scratch));
+  }
+
+  if (emit_debug_code()) {
+    // Also emit debug code to clear the cp in the top frame.
+    Mov(scratch, Operand(ExternalReference(Isolate::kContextAddress,
+                                           isolate())));
+    Str(xzr, MemOperand(scratch));
+  }
+  // Clear the frame pointer from the top frame.
+  Mov(scratch, Operand(ExternalReference(Isolate::kCEntryFPAddress,
+                                         isolate())));
+  Str(xzr, MemOperand(scratch));
+
+  // Pop the exit frame.
+  //         fp[8]: CallerPC (lr)
+  //   fp -> fp[0]: CallerFP (old fp)
+  //         fp[...]: The rest of the frame.
+  Mov(jssp, fp);
+  SetStackPointer(jssp);
+  AssertStackConsistency();
+  Pop(fp, lr);
+}
+
+
+void MacroAssembler::SetCounter(StatsCounter* counter, int value,
+                                Register scratch1, Register scratch2) {
+  if (FLAG_native_code_counters && counter->Enabled()) {
+    Mov(scratch1, value);
+    Mov(scratch2, Operand(ExternalReference(counter)));
+    Str(scratch1, MemOperand(scratch2));
+  }
+}
+
+
+void MacroAssembler::IncrementCounter(StatsCounter* counter, int value,
+                                      Register scratch1, Register scratch2) {
+  ASSERT(value != 0);
+  if (FLAG_native_code_counters && counter->Enabled()) {
+    Mov(scratch2, Operand(ExternalReference(counter)));
+    Ldr(scratch1, MemOperand(scratch2));
+    Add(scratch1, scratch1, value);
+    Str(scratch1, MemOperand(scratch2));
+  }
+}
+
+
+void MacroAssembler::DecrementCounter(StatsCounter* counter, int value,
+                                      Register scratch1, Register scratch2) {
+  IncrementCounter(counter, -value, scratch1, scratch2);
+}
+
+
+void MacroAssembler::LoadContext(Register dst, int context_chain_length) {
+  if (context_chain_length > 0) {
+    // Move up the chain of contexts to the context containing the slot.
+    Ldr(dst, MemOperand(cp, Context::SlotOffset(Context::PREVIOUS_INDEX)));
+    for (int i = 1; i < context_chain_length; i++) {
+      Ldr(dst, MemOperand(dst, Context::SlotOffset(Context::PREVIOUS_INDEX)));
+    }
+  } else {
+    // Slot is in the current function context.  Move it into the
+    // destination register in case we store into it (the write barrier
+    // cannot be allowed to destroy the context in cp).
+    Mov(dst, cp);
+  }
+}
+
+
+#ifdef ENABLE_DEBUGGER_SUPPORT
+void MacroAssembler::DebugBreak() {
+  Mov(x0, 0);
+  Mov(x1, Operand(ExternalReference(Runtime::kDebugBreak, isolate())));
+  CEntryStub ces(1);
+  ASSERT(AllowThisStubCall(&ces));
+  Call(ces.GetCode(isolate()), RelocInfo::DEBUG_BREAK);
+}
+#endif
+
+
+void MacroAssembler::PushTryHandler(StackHandler::Kind kind,
+                                    int handler_index) {
+  ASSERT(jssp.Is(StackPointer()));
+  // Adjust this code if the asserts don't hold.
+  STATIC_ASSERT(StackHandlerConstants::kSize == 5 * kPointerSize);
+  STATIC_ASSERT(StackHandlerConstants::kNextOffset == 0 * kPointerSize);
+  STATIC_ASSERT(StackHandlerConstants::kCodeOffset == 1 * kPointerSize);
+  STATIC_ASSERT(StackHandlerConstants::kStateOffset == 2 * kPointerSize);
+  STATIC_ASSERT(StackHandlerConstants::kContextOffset == 3 * kPointerSize);
+  STATIC_ASSERT(StackHandlerConstants::kFPOffset == 4 * kPointerSize);
+
+  // For the JSEntry handler, we must preserve the live registers x0-x4.
+  // (See JSEntryStub::GenerateBody().)
+
+  unsigned state =
+      StackHandler::IndexField::encode(handler_index) |
+      StackHandler::KindField::encode(kind);
+
+  // Set up the code object and the state for pushing.
+  Mov(x10, Operand(CodeObject()));
+  Mov(x11, state);
+
+  // Push the frame pointer, context, state, and code object.
+  if (kind == StackHandler::JS_ENTRY) {
+    ASSERT(Smi::FromInt(0) == 0);
+    Push(xzr, xzr, x11, x10);
+  } else {
+    Push(fp, cp, x11, x10);
+  }
+
+  // Link the current handler as the next handler.
+  Mov(x11, Operand(ExternalReference(Isolate::kHandlerAddress, isolate())));
+  Ldr(x10, MemOperand(x11));
+  Push(x10);
+  // Set this new handler as the current one.
+  Str(jssp, MemOperand(x11));
+}
+
+
+void MacroAssembler::PopTryHandler() {
+  STATIC_ASSERT(StackHandlerConstants::kNextOffset == 0);
+  Pop(x10);
+  Mov(x11, Operand(ExternalReference(Isolate::kHandlerAddress, isolate())));
+  Drop(StackHandlerConstants::kSize - kXRegSizeInBytes, kByteSizeInBytes);
+  Str(x10, MemOperand(x11));
+}
+
+
+void MacroAssembler::Allocate(int object_size,
+                              Register result,
+                              Register scratch1,
+                              Register scratch2,
+                              Label* gc_required,
+                              AllocationFlags flags) {
+  ASSERT(object_size <= Page::kMaxRegularHeapObjectSize);
+  if (!FLAG_inline_new) {
+    if (emit_debug_code()) {
+      // Trash the registers to simulate an allocation failure.
+      // We apply salt to the original zap value to easily spot the values.
+      Mov(result, (kDebugZapValue & ~0xffL) | 0x11L);
+      Mov(scratch1, (kDebugZapValue & ~0xffL) | 0x21L);
+      Mov(scratch2, (kDebugZapValue & ~0xffL) | 0x21L);
+    }
+    B(gc_required);
+    return;
+  }
+
+  ASSERT(!AreAliased(result, scratch1, scratch2, Tmp0(), Tmp1()));
+  ASSERT(result.Is64Bits() && scratch1.Is64Bits() && scratch2.Is64Bits() &&
+         Tmp0().Is64Bits() && Tmp1().Is64Bits());
+
+  // Make object size into bytes.
+  if ((flags & SIZE_IN_WORDS) != 0) {
+    object_size *= kPointerSize;
+  }
+  ASSERT(0 == (object_size & kObjectAlignmentMask));
+
+  // Check relative positions of allocation top and limit addresses.
+  // The values must be adjacent in memory to allow the use of LDP.
+  ExternalReference heap_allocation_top =
+      AllocationUtils::GetAllocationTopReference(isolate(), flags);
+  ExternalReference heap_allocation_limit =
+      AllocationUtils::GetAllocationLimitReference(isolate(), flags);
+  intptr_t top = reinterpret_cast<intptr_t>(heap_allocation_top.address());
+  intptr_t limit = reinterpret_cast<intptr_t>(heap_allocation_limit.address());
+  ASSERT((limit - top) == kPointerSize);
+
+  // Set up allocation top address and object size registers.
+  Register top_address = scratch1;
+  Register allocation_limit = scratch2;
+  Mov(top_address, Operand(heap_allocation_top));
+
+  if ((flags & RESULT_CONTAINS_TOP) == 0) {
+    // Load allocation top into result and the allocation limit.
+    Ldp(result, allocation_limit, MemOperand(top_address));
+  } else {
+    if (emit_debug_code()) {
+      // Assert that result actually contains top on entry.
+      Ldr(Tmp0(), MemOperand(top_address));
+      Cmp(result, Tmp0());
+      Check(eq, kUnexpectedAllocationTop);
+    }
+    // Load the allocation limit. 'result' already contains the allocation top.
+    Ldr(allocation_limit, MemOperand(top_address, limit - top));
+  }
+
+  // We can ignore DOUBLE_ALIGNMENT flags here because doubles and pointers have
+  // the same alignment on A64.
+  STATIC_ASSERT(kPointerAlignment == kDoubleAlignment);
+
+  // Calculate new top and bail out if new space is exhausted.
+  Adds(Tmp1(), result, object_size);
+  B(vs, gc_required);
+  Cmp(Tmp1(), allocation_limit);
+  B(hi, gc_required);
+  Str(Tmp1(), MemOperand(top_address));
+
+  // Tag the object if requested.
+  if ((flags & TAG_OBJECT) != 0) {
+    Orr(result, result, kHeapObjectTag);
+  }
+}
+
+
+void MacroAssembler::Allocate(Register object_size,
+                              Register result,
+                              Register scratch1,
+                              Register scratch2,
+                              Label* gc_required,
+                              AllocationFlags flags) {
+  if (!FLAG_inline_new) {
+    if (emit_debug_code()) {
+      // Trash the registers to simulate an allocation failure.
+      // We apply salt to the original zap value to easily spot the values.
+      Mov(result, (kDebugZapValue & ~0xffL) | 0x11L);
+      Mov(scratch1, (kDebugZapValue & ~0xffL) | 0x21L);
+      Mov(scratch2, (kDebugZapValue & ~0xffL) | 0x21L);
+    }
+    B(gc_required);
+    return;
+  }
+
+  ASSERT(!AreAliased(object_size, result, scratch1, scratch2, Tmp0(), Tmp1()));
+  ASSERT(object_size.Is64Bits() && result.Is64Bits() && scratch1.Is64Bits() &&
+         scratch2.Is64Bits() && Tmp0().Is64Bits() && Tmp1().Is64Bits());
+
+  // Check relative positions of allocation top and limit addresses.
+  // The values must be adjacent in memory to allow the use of LDP.
+  ExternalReference heap_allocation_top =
+      AllocationUtils::GetAllocationTopReference(isolate(), flags);
+  ExternalReference heap_allocation_limit =
+      AllocationUtils::GetAllocationLimitReference(isolate(), flags);
+  intptr_t top = reinterpret_cast<intptr_t>(heap_allocation_top.address());
+  intptr_t limit = reinterpret_cast<intptr_t>(heap_allocation_limit.address());
+  ASSERT((limit - top) == kPointerSize);
+
+  // Set up allocation top address and object size registers.
+  Register top_address = scratch1;
+  Register allocation_limit = scratch2;
+  Mov(top_address, Operand(heap_allocation_top));
+
+  if ((flags & RESULT_CONTAINS_TOP) == 0) {
+    // Load allocation top into result and the allocation limit.
+    Ldp(result, allocation_limit, MemOperand(top_address));
+  } else {
+    if (emit_debug_code()) {
+      // Assert that result actually contains top on entry.
+      Ldr(Tmp0(), MemOperand(top_address));
+      Cmp(result, Tmp0());
+      Check(eq, kUnexpectedAllocationTop);
+    }
+    // Load the allocation limit. 'result' already contains the allocation top.
+    Ldr(allocation_limit, MemOperand(top_address, limit - top));
+  }
+
+  // We can ignore DOUBLE_ALIGNMENT flags here because doubles and pointers have
+  // the same alignment on A64.
+  STATIC_ASSERT(kPointerAlignment == kDoubleAlignment);
+
+  // Calculate new top and bail out if new space is exhausted
+  if ((flags & SIZE_IN_WORDS) != 0) {
+    Adds(Tmp1(), result, Operand(object_size, LSL, kPointerSizeLog2));
+  } else {
+    Adds(Tmp1(), result, object_size);
+  }
+
+  if (emit_debug_code()) {
+    Tst(Tmp1(), kObjectAlignmentMask);
+    Check(eq, kUnalignedAllocationInNewSpace);
+  }
+
+  B(vs, gc_required);
+  Cmp(Tmp1(), allocation_limit);
+  B(hi, gc_required);
+  Str(Tmp1(), MemOperand(top_address));
+
+  // Tag the object if requested.
+  if ((flags & TAG_OBJECT) != 0) {
+    Orr(result, result, kHeapObjectTag);
+  }
+}
+
+
+void MacroAssembler::UndoAllocationInNewSpace(Register object,
+                                              Register scratch) {
+  ExternalReference new_space_allocation_top =
+      ExternalReference::new_space_allocation_top_address(isolate());
+
+  // Make sure the object has no tag before resetting top.
+  Bic(object, object, kHeapObjectTagMask);
+#ifdef DEBUG
+  // Check that the object un-allocated is below the current top.
+  Mov(scratch, Operand(new_space_allocation_top));
+  Ldr(scratch, MemOperand(scratch));
+  Cmp(object, scratch);
+  Check(lt, kUndoAllocationOfNonAllocatedMemory);
+#endif
+  // Write the address of the object to un-allocate as the current top.
+  Mov(scratch, Operand(new_space_allocation_top));
+  Str(object, MemOperand(scratch));
+}
+
+
+void MacroAssembler::AllocateTwoByteString(Register result,
+                                           Register length,
+                                           Register scratch1,
+                                           Register scratch2,
+                                           Register scratch3,
+                                           Label* gc_required) {
+  ASSERT(!AreAliased(result, length, scratch1, scratch2, scratch3));
+  // Calculate the number of bytes needed for the characters in the string while
+  // observing object alignment.
+  STATIC_ASSERT((SeqTwoByteString::kHeaderSize & kObjectAlignmentMask) == 0);
+  Add(scratch1, length, length);  // Length in bytes, not chars.
+  Add(scratch1, scratch1, kObjectAlignmentMask + SeqTwoByteString::kHeaderSize);
+  Bic(scratch1, scratch1, kObjectAlignmentMask);
+
+  // Allocate two-byte string in new space.
+  Allocate(scratch1,
+           result,
+           scratch2,
+           scratch3,
+           gc_required,
+           TAG_OBJECT);
+
+  // Set the map, length and hash field.
+  InitializeNewString(result,
+                      length,
+                      Heap::kStringMapRootIndex,
+                      scratch1,
+                      scratch2);
+}
+
+
+void MacroAssembler::AllocateAsciiString(Register result,
+                                         Register length,
+                                         Register scratch1,
+                                         Register scratch2,
+                                         Register scratch3,
+                                         Label* gc_required) {
+  ASSERT(!AreAliased(result, length, scratch1, scratch2, scratch3));
+  // Calculate the number of bytes needed for the characters in the string while
+  // observing object alignment.
+  STATIC_ASSERT((SeqOneByteString::kHeaderSize & kObjectAlignmentMask) == 0);
+  STATIC_ASSERT(kCharSize == 1);
+  Add(scratch1, length, kObjectAlignmentMask + SeqOneByteString::kHeaderSize);
+  Bic(scratch1, scratch1, kObjectAlignmentMask);
+
+  // Allocate ASCII string in new space.
+  Allocate(scratch1,
+           result,
+           scratch2,
+           scratch3,
+           gc_required,
+           TAG_OBJECT);
+
+  // Set the map, length and hash field.
+  InitializeNewString(result,
+                      length,
+                      Heap::kAsciiStringMapRootIndex,
+                      scratch1,
+                      scratch2);
+}
+
+
+void MacroAssembler::AllocateTwoByteConsString(Register result,
+                                               Register length,
+                                               Register scratch1,
+                                               Register scratch2,
+                                               Label* gc_required) {
+  Allocate(ConsString::kSize, result, scratch1, scratch2, gc_required,
+           TAG_OBJECT);
+
+  InitializeNewString(result,
+                      length,
+                      Heap::kConsStringMapRootIndex,
+                      scratch1,
+                      scratch2);
+}
+
+
+void MacroAssembler::AllocateAsciiConsString(Register result,
+                                             Register length,
+                                             Register scratch1,
+                                             Register scratch2,
+                                             Label* gc_required) {
+  Label allocate_new_space, install_map;
+  AllocationFlags flags = TAG_OBJECT;
+
+  ExternalReference high_promotion_mode = ExternalReference::
+      new_space_high_promotion_mode_active_address(isolate());
+  Mov(scratch1, Operand(high_promotion_mode));
+  Ldr(scratch1, MemOperand(scratch1));
+  Cbz(scratch1, &allocate_new_space);
+
+  Allocate(ConsString::kSize,
+           result,
+           scratch1,
+           scratch2,
+           gc_required,
+           static_cast<AllocationFlags>(flags | PRETENURE_OLD_POINTER_SPACE));
+
+  B(&install_map);
+
+  Bind(&allocate_new_space);
+  Allocate(ConsString::kSize,
+           result,
+           scratch1,
+           scratch2,
+           gc_required,
+           flags);
+
+  Bind(&install_map);
+
+  InitializeNewString(result,
+                      length,
+                      Heap::kConsAsciiStringMapRootIndex,
+                      scratch1,
+                      scratch2);
+}
+
+
+void MacroAssembler::AllocateTwoByteSlicedString(Register result,
+                                                 Register length,
+                                                 Register scratch1,
+                                                 Register scratch2,
+                                                 Label* gc_required) {
+  ASSERT(!AreAliased(result, length, scratch1, scratch2));
+  Allocate(SlicedString::kSize, result, scratch1, scratch2, gc_required,
+           TAG_OBJECT);
+
+  InitializeNewString(result,
+                      length,
+                      Heap::kSlicedStringMapRootIndex,
+                      scratch1,
+                      scratch2);
+}
+
+
+void MacroAssembler::AllocateAsciiSlicedString(Register result,
+                                               Register length,
+                                               Register scratch1,
+                                               Register scratch2,
+                                               Label* gc_required) {
+  ASSERT(!AreAliased(result, length, scratch1, scratch2));
+  Allocate(SlicedString::kSize, result, scratch1, scratch2, gc_required,
+           TAG_OBJECT);
+
+  InitializeNewString(result,
+                      length,
+                      Heap::kSlicedAsciiStringMapRootIndex,
+                      scratch1,
+                      scratch2);
+}
+
+
+// Allocates a heap number or jumps to the need_gc label if the young space
+// is full and a scavenge is needed.
+void MacroAssembler::AllocateHeapNumber(Register result,
+                                        Label* gc_required,
+                                        Register scratch1,
+                                        Register scratch2,
+                                        Register heap_number_map) {
+  // Allocate an object in the heap for the heap number and tag it as a heap
+  // object.
+  Allocate(HeapNumber::kSize, result, scratch1, scratch2, gc_required,
+           TAG_OBJECT);
+
+  // Store heap number map in the allocated object.
+  if (heap_number_map.Is(NoReg)) {
+    heap_number_map = scratch1;
+    LoadRoot(heap_number_map, Heap::kHeapNumberMapRootIndex);
+  }
+  AssertRegisterIsRoot(heap_number_map, Heap::kHeapNumberMapRootIndex);
+  Str(heap_number_map, FieldMemOperand(result, HeapObject::kMapOffset));
+}
+
+
+void MacroAssembler::AllocateHeapNumberWithValue(Register result,
+                                                 DoubleRegister value,
+                                                 Label* gc_required,
+                                                 Register scratch1,
+                                                 Register scratch2,
+                                                 Register heap_number_map) {
+  // TODO(all): Check if it would be more efficient to use STP to store both
+  // the map and the value.
+  AllocateHeapNumber(result, gc_required, scratch1, scratch2, heap_number_map);
+  Str(value, FieldMemOperand(result, HeapNumber::kValueOffset));
+}
+
+
+void MacroAssembler::JumpIfObjectType(Register object,
+                                      Register map,
+                                      Register type_reg,
+                                      InstanceType type,
+                                      Label* if_cond_pass,
+                                      Condition cond) {
+  CompareObjectType(object, map, type_reg, type);
+  B(cond, if_cond_pass);
+}
+
+
+void MacroAssembler::JumpIfNotObjectType(Register object,
+                                         Register map,
+                                         Register type_reg,
+                                         InstanceType type,
+                                         Label* if_not_object) {
+  JumpIfObjectType(object, map, type_reg, type, if_not_object, ne);
+}
+
+
+// Sets condition flags based on comparison, and returns type in type_reg.
+void MacroAssembler::CompareObjectType(Register object,
+                                       Register map,
+                                       Register type_reg,
+                                       InstanceType type) {
+  Ldr(map, FieldMemOperand(object, HeapObject::kMapOffset));
+  CompareInstanceType(map, type_reg, type);
+}
+
+
+// Sets condition flags based on comparison, and returns type in type_reg.
+void MacroAssembler::CompareInstanceType(Register map,
+                                         Register type_reg,
+                                         InstanceType type) {
+  Ldrb(type_reg, FieldMemOperand(map, Map::kInstanceTypeOffset));
+  Cmp(type_reg, type);
+}
+
+
+void MacroAssembler::CompareMap(Register obj,
+                                Register scratch,
+                                Handle<Map> map,
+                                Label* early_success) {
+  // TODO(jbramley): The early_success label isn't used. Remove it.
+  Ldr(scratch, FieldMemOperand(obj, HeapObject::kMapOffset));
+  CompareMap(scratch, map, early_success);
+}
+
+
+void MacroAssembler::CompareMap(Register obj_map,
+                                Handle<Map> map,
+                                Label* early_success) {
+  // TODO(jbramley): The early_success label isn't used. Remove it.
+  Cmp(obj_map, Operand(map));
+}
+
+
+void MacroAssembler::CheckMap(Register obj,
+                              Register scratch,
+                              Handle<Map> map,
+                              Label* fail,
+                              SmiCheckType smi_check_type) {
+  if (smi_check_type == DO_SMI_CHECK) {
+    JumpIfSmi(obj, fail);
+  }
+
+  Label success;
+  CompareMap(obj, scratch, map, &success);
+  B(ne, fail);
+  Bind(&success);
+}
+
+
+void MacroAssembler::CheckMap(Register obj,
+                              Register scratch,
+                              Heap::RootListIndex index,
+                              Label* fail,
+                              SmiCheckType smi_check_type) {
+  if (smi_check_type == DO_SMI_CHECK) {
+    JumpIfSmi(obj, fail);
+  }
+  Ldr(scratch, FieldMemOperand(obj, HeapObject::kMapOffset));
+  JumpIfNotRoot(scratch, index, fail);
+}
+
+
+void MacroAssembler::CheckMap(Register obj_map,
+                              Handle<Map> map,
+                              Label* fail,
+                              SmiCheckType smi_check_type) {
+  if (smi_check_type == DO_SMI_CHECK) {
+    JumpIfSmi(obj_map, fail);
+  }
+  Label success;
+  CompareMap(obj_map, map, &success);
+  B(ne, fail);
+  Bind(&success);
+}
+
+
+void MacroAssembler::DispatchMap(Register obj,
+                                 Register scratch,
+                                 Handle<Map> map,
+                                 Handle<Code> success,
+                                 SmiCheckType smi_check_type) {
+  Label fail;
+  if (smi_check_type == DO_SMI_CHECK) {
+    JumpIfSmi(obj, &fail);
+  }
+  Ldr(scratch, FieldMemOperand(obj, HeapObject::kMapOffset));
+  Cmp(scratch, Operand(map));
+  B(ne, &fail);
+  Jump(success, RelocInfo::CODE_TARGET);
+  Bind(&fail);
+}
+
+
+void MacroAssembler::TestMapBitfield(Register object, uint64_t mask) {
+  Ldr(Tmp0(), FieldMemOperand(object, HeapObject::kMapOffset));
+  Ldrb(Tmp0(), FieldMemOperand(Tmp0(), Map::kBitFieldOffset));
+  Tst(Tmp0(), mask);
+}
+
+
+void MacroAssembler::LoadElementsKind(Register result, Register object) {
+  // Load map.
+  __ Ldr(result, FieldMemOperand(object, HeapObject::kMapOffset));
+  // Load the map's "bit field 2".
+  __ Ldrb(result, FieldMemOperand(result, Map::kBitField2Offset));
+  // Retrieve elements_kind from bit field 2.
+  __ Ubfx(result, result, Map::kElementsKindShift, Map::kElementsKindBitCount);
+}
+
+
+void MacroAssembler::TryGetFunctionPrototype(Register function,
+                                             Register result,
+                                             Register scratch,
+                                             Label* miss,
+                                             BoundFunctionAction action) {
+  ASSERT(!AreAliased(function, result, scratch));
+
+  // Check that the receiver isn't a smi.
+  JumpIfSmi(function, miss);
+
+  // Check that the function really is a function. Load map into result reg.
+  JumpIfNotObjectType(function, result, scratch, JS_FUNCTION_TYPE, miss);
+
+  if (action == kMissOnBoundFunction) {
+    Register scratch_w = scratch.W();
+    Ldr(scratch,
+        FieldMemOperand(function, JSFunction::kSharedFunctionInfoOffset));
+    // On 64-bit platforms, compiler hints field is not a smi. See definition of
+    // kCompilerHintsOffset in src/objects.h.
+    Ldr(scratch_w,
+        FieldMemOperand(scratch, SharedFunctionInfo::kCompilerHintsOffset));
+    Tbnz(scratch, SharedFunctionInfo::kBoundFunction, miss);
+  }
+
+  // Make sure that the function has an instance prototype.
+  Label non_instance;
+  Ldrb(scratch, FieldMemOperand(result, Map::kBitFieldOffset));
+  Tbnz(scratch, Map::kHasNonInstancePrototype, &non_instance);
+
+  // Get the prototype or initial map from the function.
+  Ldr(result,
+      FieldMemOperand(function, JSFunction::kPrototypeOrInitialMapOffset));
+
+  // If the prototype or initial map is the hole, don't return it and simply
+  // miss the cache instead. This will allow us to allocate a prototype object
+  // on-demand in the runtime system.
+  JumpIfRoot(result, Heap::kTheHoleValueRootIndex, miss);
+
+  // If the function does not have an initial map, we're done.
+  Label done;
+  JumpIfNotObjectType(result, scratch, scratch, MAP_TYPE, &done);
+
+  // Get the prototype from the initial map.
+  Ldr(result, FieldMemOperand(result, Map::kPrototypeOffset));
+  B(&done);
+
+  // Non-instance prototype: fetch prototype from constructor field in initial
+  // map.
+  Bind(&non_instance);
+  Ldr(result, FieldMemOperand(result, Map::kConstructorOffset));
+
+  // All done.
+  Bind(&done);
+}
+
+
+void MacroAssembler::CompareRoot(const Register& obj,
+                                 Heap::RootListIndex index) {
+  ASSERT(!AreAliased(obj, Tmp0()));
+  LoadRoot(Tmp0(), index);
+  Cmp(obj, Tmp0());
+}
+
+
+void MacroAssembler::JumpIfRoot(const Register& obj,
+                                Heap::RootListIndex index,
+                                Label* if_equal) {
+  CompareRoot(obj, index);
+  B(eq, if_equal);
+}
+
+
+void MacroAssembler::JumpIfNotRoot(const Register& obj,
+                                   Heap::RootListIndex index,
+                                   Label* if_not_equal) {
+  CompareRoot(obj, index);
+  B(ne, if_not_equal);
+}
+
+
+void MacroAssembler::CompareAndSplit(const Register& lhs,
+                                     const Operand& rhs,
+                                     Condition cond,
+                                     Label* if_true,
+                                     Label* if_false,
+                                     Label* fall_through) {
+  if ((if_true == if_false) && (if_false == fall_through)) {
+    // Fall through.
+  } else if (if_true == if_false) {
+    B(if_true);
+  } else if (if_false == fall_through) {
+    CompareAndBranch(lhs, rhs, cond, if_true);
+  } else if (if_true == fall_through) {
+    CompareAndBranch(lhs, rhs, InvertCondition(cond), if_false);
+  } else {
+    CompareAndBranch(lhs, rhs, cond, if_true);
+    B(if_false);
+  }
+}
+
+
+void MacroAssembler::TestAndSplit(const Register& reg,
+                                  uint64_t bit_pattern,
+                                  Label* if_all_clear,
+                                  Label* if_any_set,
+                                  Label* fall_through) {
+  if ((if_all_clear == if_any_set) && (if_any_set == fall_through)) {
+    // Fall through.
+  } else if (if_all_clear == if_any_set) {
+    B(if_all_clear);
+  } else if (if_all_clear == fall_through) {
+    TestAndBranchIfAnySet(reg, bit_pattern, if_any_set);
+  } else if (if_any_set == fall_through) {
+    TestAndBranchIfAllClear(reg, bit_pattern, if_all_clear);
+  } else {
+    TestAndBranchIfAnySet(reg, bit_pattern, if_any_set);
+    B(if_all_clear);
+  }
+}
+
+
+void MacroAssembler::CheckFastElements(Register map,
+                                       Register scratch,
+                                       Label* fail) {
+  STATIC_ASSERT(FAST_SMI_ELEMENTS == 0);
+  STATIC_ASSERT(FAST_HOLEY_SMI_ELEMENTS == 1);
+  STATIC_ASSERT(FAST_ELEMENTS == 2);
+  STATIC_ASSERT(FAST_HOLEY_ELEMENTS == 3);
+  Ldrb(scratch, FieldMemOperand(map, Map::kBitField2Offset));
+  Cmp(scratch, Map::kMaximumBitField2FastHoleyElementValue);
+  B(hi, fail);
+}
+
+
+void MacroAssembler::CheckFastObjectElements(Register map,
+                                             Register scratch,
+                                             Label* fail) {
+  STATIC_ASSERT(FAST_SMI_ELEMENTS == 0);
+  STATIC_ASSERT(FAST_HOLEY_SMI_ELEMENTS == 1);
+  STATIC_ASSERT(FAST_ELEMENTS == 2);
+  STATIC_ASSERT(FAST_HOLEY_ELEMENTS == 3);
+  Ldrb(scratch, FieldMemOperand(map, Map::kBitField2Offset));
+  Cmp(scratch, Operand(Map::kMaximumBitField2FastHoleySmiElementValue));
+  // If cond==ls, set cond=hi, otherwise compare.
+  Ccmp(scratch,
+       Operand(Map::kMaximumBitField2FastHoleyElementValue), CFlag, hi);
+  B(hi, fail);
+}
+
+
+void MacroAssembler::CheckFastSmiElements(Register map,
+                                          Register scratch,
+                                          Label* fail) {
+  STATIC_ASSERT(FAST_SMI_ELEMENTS == 0);
+  STATIC_ASSERT(FAST_HOLEY_SMI_ELEMENTS == 1);
+  Ldrb(scratch, FieldMemOperand(map, Map::kBitField2Offset));
+  Cmp(scratch, Map::kMaximumBitField2FastHoleySmiElementValue);
+  B(hi, fail);
+}
+
+
+// Note: The ARM version of this clobbers elements_reg, but this version does
+// not. Some uses of this in A64 assume that elements_reg will be preserved.
+void MacroAssembler::StoreNumberToDoubleElements(Register value_reg,
+                                                 Register key_reg,
+                                                 Register elements_reg,
+                                                 Register scratch1,
+                                                 FPRegister fpscratch1,
+                                                 FPRegister fpscratch2,
+                                                 Label* fail,
+                                                 int elements_offset) {
+  ASSERT(!AreAliased(value_reg, key_reg, elements_reg, scratch1));
+  Label store_num;
+
+  // Speculatively convert the smi to a double - all smis can be exactly
+  // represented as a double.
+  SmiUntagToDouble(fpscratch1, value_reg, kSpeculativeUntag);
+
+  // If value_reg is a smi, we're done.
+  JumpIfSmi(value_reg, &store_num);
+
+  // Ensure that the object is a heap number.
+  CheckMap(value_reg, scratch1, isolate()->factory()->heap_number_map(),
+           fail, DONT_DO_SMI_CHECK);
+
+  Ldr(fpscratch1, FieldMemOperand(value_reg, HeapNumber::kValueOffset));
+  Fmov(fpscratch2, FixedDoubleArray::canonical_not_the_hole_nan_as_double());
+
+  // Check for NaN by comparing the number to itself: NaN comparison will
+  // report unordered, indicated by the overflow flag being set.
+  Fcmp(fpscratch1, fpscratch1);
+  Fcsel(fpscratch1, fpscratch2, fpscratch1, vs);
+
+  // Store the result.
+  Bind(&store_num);
+  Add(scratch1, elements_reg,
+      Operand::UntagSmiAndScale(key_reg, kDoubleSizeLog2));
+  Str(fpscratch1,
+      FieldMemOperand(scratch1,
+                      FixedDoubleArray::kHeaderSize - elements_offset));
+}
+
+
+bool MacroAssembler::AllowThisStubCall(CodeStub* stub) {
+  return has_frame_ || !stub->SometimesSetsUpAFrame();
+}
+
+
+void MacroAssembler::IndexFromHash(Register hash, Register index) {
+  // If the hash field contains an array index pick it out. The assert checks
+  // that the constants for the maximum number of digits for an array index
+  // cached in the hash field and the number of bits reserved for it does not
+  // conflict.
+  ASSERT(TenToThe(String::kMaxCachedArrayIndexLength) <
+         (1 << String::kArrayIndexValueBits));
+  // We want the smi-tagged index in key.  kArrayIndexValueMask has zeros in
+  // the low kHashShift bits.
+  STATIC_ASSERT(kSmiTag == 0);
+  Ubfx(hash, hash, String::kHashShift, String::kArrayIndexValueBits);
+  SmiTag(index, hash);
+}
+
+
+void MacroAssembler::EmitSeqStringSetCharCheck(
+    Register string,
+    Register index,
+    SeqStringSetCharCheckIndexType index_type,
+    Register scratch,
+    uint32_t encoding_mask) {
+  ASSERT(!AreAliased(string, index, scratch));
+
+  if (index_type == kIndexIsSmi) {
+    AssertSmi(index);
+  }
+
+  // Check that string is an object.
+  AssertNotSmi(string, kNonObject);
+
+  // Check that string has an appropriate map.
+  Ldr(scratch, FieldMemOperand(string, HeapObject::kMapOffset));
+  Ldrb(scratch, FieldMemOperand(scratch, Map::kInstanceTypeOffset));
+
+  And(scratch, scratch, kStringRepresentationMask | kStringEncodingMask);
+  Cmp(scratch, encoding_mask);
+  Check(eq, kUnexpectedStringType);
+
+  Ldr(scratch, FieldMemOperand(string, String::kLengthOffset));
+  Cmp(index, index_type == kIndexIsSmi ? scratch : Operand::UntagSmi(scratch));
+  Check(lt, kIndexIsTooLarge);
+
+  ASSERT_EQ(0, Smi::FromInt(0));
+  Cmp(index, 0);
+  Check(ge, kIndexIsNegative);
+}
+
+
+void MacroAssembler::CheckAccessGlobalProxy(Register holder_reg,
+                                            Register scratch,
+                                            Label* miss) {
+  // TODO(jbramley): Sort out the uses of Tmp0() and Tmp1() in this function.
+  // The ARM version takes two scratch registers, and that should be enough for
+  // all of the checks.
+
+  Label same_contexts;
+
+  ASSERT(!AreAliased(holder_reg, scratch));
+
+  // Load current lexical context from the stack frame.
+  Ldr(scratch, MemOperand(fp, StandardFrameConstants::kContextOffset));
+  // In debug mode, make sure the lexical context is set.
+#ifdef DEBUG
+  Cmp(scratch, 0);
+  Check(ne, kWeShouldNotHaveAnEmptyLexicalContext);
+#endif
+
+  // Load the native context of the current context.
+  int offset =
+      Context::kHeaderSize + Context::GLOBAL_OBJECT_INDEX * kPointerSize;
+  Ldr(scratch, FieldMemOperand(scratch, offset));
+  Ldr(scratch, FieldMemOperand(scratch, GlobalObject::kNativeContextOffset));
+
+  // Check the context is a native context.
+  if (emit_debug_code()) {
+    // Read the first word and compare to the global_context_map.
+    Register temp = Tmp1();
+    Ldr(temp, FieldMemOperand(scratch, HeapObject::kMapOffset));
+    CompareRoot(temp, Heap::kNativeContextMapRootIndex);
+    Check(eq, kExpectedNativeContext);
+  }
+
+  // Check if both contexts are the same.
+  ldr(Tmp0(), FieldMemOperand(holder_reg, JSGlobalProxy::kNativeContextOffset));
+  cmp(scratch, Tmp0());
+  b(&same_contexts, eq);
+
+  // Check the context is a native context.
+  if (emit_debug_code()) {
+    // Move Tmp0() into a different register, as CompareRoot will use it.
+    Register temp = Tmp1();
+    mov(temp, Tmp0());
+    CompareRoot(temp, Heap::kNullValueRootIndex);
+    Check(ne, kExpectedNonNullContext);
+
+    Ldr(temp, FieldMemOperand(temp, HeapObject::kMapOffset));
+    CompareRoot(temp, Heap::kNativeContextMapRootIndex);
+    Check(eq, kExpectedNativeContext);
+
+    // Let's consider that Tmp0() has been cloberred by the MacroAssembler.
+    // We reload it with its value.
+    ldr(Tmp0(), FieldMemOperand(holder_reg,
+                                JSGlobalProxy::kNativeContextOffset));
+  }
+
+  // Check that the security token in the calling global object is
+  // compatible with the security token in the receiving global
+  // object.
+  int token_offset = Context::kHeaderSize +
+                     Context::SECURITY_TOKEN_INDEX * kPointerSize;
+
+  ldr(scratch, FieldMemOperand(scratch, token_offset));
+  ldr(Tmp0(), FieldMemOperand(Tmp0(), token_offset));
+  cmp(scratch, Tmp0());
+  b(miss, ne);
+
+  bind(&same_contexts);
+}
+
+
+// Compute the hash code from the untagged key. This must be kept in sync with
+// ComputeIntegerHash in utils.h and KeyedLoadGenericElementStub in
+// code-stub-hydrogen.cc
+void MacroAssembler::GetNumberHash(Register key, Register scratch) {
+  ASSERT(!AreAliased(key, scratch));
+
+  // Xor original key with a seed.
+  LoadRoot(scratch, Heap::kHashSeedRootIndex);
+  Eor(key, key, Operand::UntagSmi(scratch));
+
+  // The algorithm uses 32-bit integer values.
+  key = key.W();
+  scratch = scratch.W();
+
+  // Compute the hash code from the untagged key.  This must be kept in sync
+  // with ComputeIntegerHash in utils.h.
+  //
+  // hash = ~hash + (hash <<1 15);
+  Mvn(scratch, key);
+  Add(key, scratch, Operand(key, LSL, 15));
+  // hash = hash ^ (hash >> 12);
+  Eor(key, key, Operand(key, LSR, 12));
+  // hash = hash + (hash << 2);
+  Add(key, key, Operand(key, LSL, 2));
+  // hash = hash ^ (hash >> 4);
+  Eor(key, key, Operand(key, LSR, 4));
+  // hash = hash * 2057;
+  Mov(scratch, Operand(key, LSL, 11));
+  Add(key, key, Operand(key, LSL, 3));
+  Add(key, key, scratch);
+  // hash = hash ^ (hash >> 16);
+  Eor(key, key, Operand(key, LSR, 16));
+}
+
+
+void MacroAssembler::LoadFromNumberDictionary(Label* miss,
+                                              Register elements,
+                                              Register key,
+                                              Register result,
+                                              Register scratch0,
+                                              Register scratch1,
+                                              Register scratch2,
+                                              Register scratch3) {
+  ASSERT(!AreAliased(elements, key, scratch0, scratch1, scratch2, scratch3));
+
+  Label done;
+
+  SmiUntag(scratch0, key);
+  GetNumberHash(scratch0, scratch1);
+
+  // Compute the capacity mask.
+  Ldrsw(scratch1,
+        UntagSmiFieldMemOperand(elements,
+                                SeededNumberDictionary::kCapacityOffset));
+  Sub(scratch1, scratch1, 1);
+
+  // Generate an unrolled loop that performs a few probes before giving up.
+  for (int i = 0; i < kNumberDictionaryProbes; i++) {
+    // Compute the masked index: (hash + i + i * i) & mask.
+    if (i > 0) {
+      Add(scratch2, scratch0, SeededNumberDictionary::GetProbeOffset(i));
+    } else {
+      Mov(scratch2, scratch0);
+    }
+    And(scratch2, scratch2, scratch1);
+
+    // Scale the index by multiplying by the element size.
+    ASSERT(SeededNumberDictionary::kEntrySize == 3);
+    Add(scratch2, scratch2, Operand(scratch2, LSL, 1));
+
+    // Check if the key is identical to the name.
+    Add(scratch2, elements, Operand(scratch2, LSL, kPointerSizeLog2));
+    Ldr(scratch3,
+        FieldMemOperand(scratch2,
+                        SeededNumberDictionary::kElementsStartOffset));
+    Cmp(key, scratch3);
+    if (i != (kNumberDictionaryProbes - 1)) {
+      B(eq, &done);
+    } else {
+      B(ne, miss);
+    }
+  }
+
+  Bind(&done);
+  // Check that the value is a normal property.
+  const int kDetailsOffset =
+      SeededNumberDictionary::kElementsStartOffset + 2 * kPointerSize;
+  Ldrsw(scratch1, UntagSmiFieldMemOperand(scratch2, kDetailsOffset));
+  TestAndBranchIfAnySet(scratch1, PropertyDetails::TypeField::kMask, miss);
+
+  // Get the value at the masked, scaled index and return.
+  const int kValueOffset =
+      SeededNumberDictionary::kElementsStartOffset + kPointerSize;
+  Ldr(result, FieldMemOperand(scratch2, kValueOffset));
+}
+
+
+void MacroAssembler::RememberedSetHelper(Register object,  // For debug tests.
+                                         Register address,
+                                         Register scratch,
+                                         SaveFPRegsMode fp_mode,
+                                         RememberedSetFinalAction and_then) {
+  ASSERT(!AreAliased(object, address, scratch));
+  Label done, store_buffer_overflow;
+  if (emit_debug_code()) {
+    Label ok;
+    JumpIfNotInNewSpace(object, &ok);
+    Abort(kRememberedSetPointerInNewSpace);
+    bind(&ok);
+  }
+  // Load store buffer top.
+  Mov(Tmp0(), Operand(ExternalReference::store_buffer_top(isolate())));
+  Ldr(scratch, MemOperand(Tmp0()));
+  // Store pointer to buffer and increment buffer top.
+  Str(address, MemOperand(scratch, kPointerSize, PostIndex));
+  // Write back new top of buffer.
+  Str(scratch, MemOperand(Tmp0()));
+  // Call stub on end of buffer.
+  // Check for end of buffer.
+  ASSERT(StoreBuffer::kStoreBufferOverflowBit ==
+         (1 << (14 + kPointerSizeLog2)));
+  if (and_then == kFallThroughAtEnd) {
+    Tbz(scratch, (14 + kPointerSizeLog2), &done);
+  } else {
+    ASSERT(and_then == kReturnAtEnd);
+    Tbnz(scratch, (14 + kPointerSizeLog2), &store_buffer_overflow);
+    Ret();
+  }
+
+  Bind(&store_buffer_overflow);
+  Push(lr);
+  StoreBufferOverflowStub store_buffer_overflow_stub =
+      StoreBufferOverflowStub(fp_mode);
+  CallStub(&store_buffer_overflow_stub);
+  Pop(lr);
+
+  Bind(&done);
+  if (and_then == kReturnAtEnd) {
+    Ret();
+  }
+}
+
+
+void MacroAssembler::PopSafepointRegisters() {
+  const int num_unsaved = kNumSafepointRegisters - kNumSafepointSavedRegisters;
+  PopXRegList(kSafepointSavedRegisters);
+  Drop(num_unsaved);
+}
+
+
+void MacroAssembler::PushSafepointRegisters() {
+  // Safepoints expect a block of kNumSafepointRegisters values on the stack, so
+  // adjust the stack for unsaved registers.
+  const int num_unsaved = kNumSafepointRegisters - kNumSafepointSavedRegisters;
+  ASSERT(num_unsaved >= 0);
+  Claim(num_unsaved);
+  PushXRegList(kSafepointSavedRegisters);
+}
+
+
+void MacroAssembler::PushSafepointFPRegisters() {
+  PushCPURegList(CPURegList(CPURegister::kFPRegister, kDRegSize,
+                            FPRegister::kAllocatableFPRegisters));
+}
+
+
+void MacroAssembler::PopSafepointFPRegisters() {
+  PopCPURegList(CPURegList(CPURegister::kFPRegister, kDRegSize,
+                           FPRegister::kAllocatableFPRegisters));
+}
+
+
+int MacroAssembler::SafepointRegisterStackIndex(int reg_code) {
+  // Make sure the safepoint registers list is what we expect.
+  ASSERT(CPURegList::GetSafepointSavedRegisters().list() == 0x6ffcffff);
+
+  // Safepoint registers are stored contiguously on the stack, but not all the
+  // registers are saved. The following registers are excluded:
+  //  - x16 and x17 (ip0 and ip1) because they shouldn't be preserved outside of
+  //    the macro assembler.
+  //  - x28 (jssp) because JS stack pointer doesn't need to be included in
+  //    safepoint registers.
+  //  - x31 (csp) because the system stack pointer doesn't need to be included
+  //    in safepoint registers.
+  //
+  // This function implements the mapping of register code to index into the
+  // safepoint register slots.
+  if ((reg_code >= 0) && (reg_code <= 15)) {
+    return reg_code;
+  } else if ((reg_code >= 18) && (reg_code <= 27)) {
+    // Skip ip0 and ip1.
+    return reg_code - 2;
+  } else if ((reg_code == 29) || (reg_code == 30)) {
+    // Also skip jssp.
+    return reg_code - 3;
+  } else {
+    // This register has no safepoint register slot.
+    UNREACHABLE();
+    return -1;
+  }
+}
+
+
+void MacroAssembler::CheckPageFlagSet(const Register& object,
+                                      const Register& scratch,
+                                      int mask,
+                                      Label* if_any_set) {
+  And(scratch, object, ~Page::kPageAlignmentMask);
+  Ldr(scratch, MemOperand(scratch, MemoryChunk::kFlagsOffset));
+  TestAndBranchIfAnySet(scratch, mask, if_any_set);
+}
+
+
+void MacroAssembler::CheckPageFlagClear(const Register& object,
+                                        const Register& scratch,
+                                        int mask,
+                                        Label* if_all_clear) {
+  And(scratch, object, ~Page::kPageAlignmentMask);
+  Ldr(scratch, MemOperand(scratch, MemoryChunk::kFlagsOffset));
+  TestAndBranchIfAllClear(scratch, mask, if_all_clear);
+}
+
+
+void MacroAssembler::RecordWriteField(
+    Register object,
+    int offset,
+    Register value,
+    Register scratch,
+    LinkRegisterStatus lr_status,
+    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 the 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 offset must be a multiple of kPointerSize.
+  ASSERT(IsAligned(offset, kPointerSize));
+
+  Add(scratch, object, offset - kHeapObjectTag);
+  if (emit_debug_code()) {
+    Label ok;
+    Tst(scratch, (1 << kPointerSizeLog2) - 1);
+    B(eq, &ok);
+    Abort(kUnalignedCellInWriteBarrier);
+    Bind(&ok);
+  }
+
+  RecordWrite(object,
+              scratch,
+              value,
+              lr_status,
+              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()) {
+    Mov(value, Operand(BitCast<int64_t>(kZapValue + 4)));
+    Mov(scratch, Operand(BitCast<int64_t>(kZapValue + 8)));
+  }
+}
+
+
+// Will clobber: object, address, value, Tmp0(), Tmp1().
+// If lr_status is kLRHasBeenSaved, lr will also be clobbered.
+//
+// The register 'object' contains a heap object pointer. The heap object tag is
+// shifted away.
+void MacroAssembler::RecordWrite(Register object,
+                                 Register address,
+                                 Register value,
+                                 LinkRegisterStatus lr_status,
+                                 SaveFPRegsMode fp_mode,
+                                 RememberedSetAction remembered_set_action,
+                                 SmiCheck smi_check) {
+  ASM_LOCATION("MacroAssembler::RecordWrite");
+  ASSERT(!AreAliased(object, value));
+
+  if (emit_debug_code()) {
+    Ldr(Tmp0(), MemOperand(address));
+    Cmp(Tmp0(), value);
+    Check(eq, kWrongAddressOrValuePassedToRecordWrite);
+  }
+
+  // Count number of write barriers in generated code.
+  isolate()->counters()->write_barriers_static()->Increment();
+  // TODO(mstarzinger): Dynamic counter missing.
+
+  // 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) {
+    ASSERT_EQ(0, kSmiTag);
+    JumpIfSmi(value, &done);
+  }
+
+  CheckPageFlagClear(value,
+                     value,  // Used as scratch.
+                     MemoryChunk::kPointersToHereAreInterestingMask,
+                     &done);
+  CheckPageFlagClear(object,
+                     value,  // Used as scratch.
+                     MemoryChunk::kPointersFromHereAreInterestingMask,
+                     &done);
+
+  // Record the actual write.
+  if (lr_status == kLRHasNotBeenSaved) {
+    Push(lr);
+  }
+  RecordWriteStub stub(object, value, address, remembered_set_action, fp_mode);
+  CallStub(&stub);
+  if (lr_status == kLRHasNotBeenSaved) {
+    Pop(lr);
+  }
+
+  Bind(&done);
+
+  // Clobber clobbered registers when running with the debug-code flag
+  // turned on to provoke errors.
+  if (emit_debug_code()) {
+    Mov(address, Operand(BitCast<int64_t>(kZapValue + 12)));
+    Mov(value, Operand(BitCast<int64_t>(kZapValue + 16)));
+  }
+}
+
+
+void MacroAssembler::AssertHasValidColor(const Register& reg) {
+  if (emit_debug_code()) {
+    // The bit sequence is backward. The first character in the string
+    // represents the least significant bit.
+    ASSERT(strcmp(Marking::kImpossibleBitPattern, "01") == 0);
+
+    Label color_is_valid;
+    Tbnz(reg, 0, &color_is_valid);
+    Tbz(reg, 1, &color_is_valid);
+    Abort(kUnexpectedColorFound);
+    Bind(&color_is_valid);
+  }
+}
+
+
+void MacroAssembler::GetMarkBits(Register addr_reg,
+                                 Register bitmap_reg,
+                                 Register shift_reg) {
+  ASSERT(!AreAliased(addr_reg, bitmap_reg, shift_reg, no_reg));
+  // addr_reg is divided into fields:
+  // |63        page base        20|19    high      8|7   shift   3|2  0|
+  // 'high' gives the index of the cell holding color bits for the object.
+  // 'shift' gives the offset in the cell for this object's color.
+  const int kShiftBits = kPointerSizeLog2 + Bitmap::kBitsPerCellLog2;
+  Ubfx(Tmp0(), addr_reg, kShiftBits, kPageSizeBits - kShiftBits);
+  Bic(bitmap_reg, addr_reg, Page::kPageAlignmentMask);
+  Add(bitmap_reg, bitmap_reg, Operand(Tmp0(), LSL, Bitmap::kBytesPerCellLog2));
+  // bitmap_reg:
+  // |63        page base        20|19 zeros 15|14      high      3|2  0|
+  Ubfx(shift_reg, addr_reg, kPointerSizeLog2, Bitmap::kBitsPerCellLog2);
+}
+
+
+void MacroAssembler::HasColor(Register object,
+                              Register bitmap_scratch,
+                              Register shift_scratch,
+                              Label* has_color,
+                              int first_bit,
+                              int second_bit) {
+  // See mark-compact.h for color definitions.
+  ASSERT(!AreAliased(object, bitmap_scratch, shift_scratch));
+
+  GetMarkBits(object, bitmap_scratch, shift_scratch);
+  Ldr(bitmap_scratch, MemOperand(bitmap_scratch, MemoryChunk::kHeaderSize));
+  // Shift the bitmap down to get the color of the object in bits [1:0].
+  Lsr(bitmap_scratch, bitmap_scratch, shift_scratch);
+
+  AssertHasValidColor(bitmap_scratch);
+
+  // These bit sequences are backwards. The first character in the string
+  // represents the least significant bit.
+  ASSERT(strcmp(Marking::kWhiteBitPattern, "00") == 0);
+  ASSERT(strcmp(Marking::kBlackBitPattern, "10") == 0);
+  ASSERT(strcmp(Marking::kGreyBitPattern, "11") == 0);
+
+  // Check for the color.
+  if (first_bit == 0) {
+    // Checking for white.
+    ASSERT(second_bit == 0);
+    // We only need to test the first bit.
+    Tbz(bitmap_scratch, 0, has_color);
+  } else {
+    Label other_color;
+    // Checking for grey or black.
+    Tbz(bitmap_scratch, 0, &other_color);
+    if (second_bit == 0) {
+      Tbz(bitmap_scratch, 1, has_color);
+    } else {
+      Tbnz(bitmap_scratch, 1, has_color);
+    }
+    Bind(&other_color);
+  }
+
+  // Fall through if it does not have the right color.
+}
+
+
+void MacroAssembler::CheckMapDeprecated(Handle<Map> map,
+                                        Register scratch,
+                                        Label* if_deprecated) {
+  if (map->CanBeDeprecated()) {
+    Mov(scratch, Operand(map));
+    Ldrsw(scratch, UntagSmiFieldMemOperand(scratch, Map::kBitField3Offset));
+    TestAndBranchIfAnySet(scratch, Map::Deprecated::kMask, if_deprecated);
+  }
+}
+
+
+void MacroAssembler::JumpIfBlack(Register object,
+                                 Register scratch0,
+                                 Register scratch1,
+                                 Label* on_black) {
+  ASSERT(strcmp(Marking::kBlackBitPattern, "10") == 0);
+  HasColor(object, scratch0, scratch1, on_black, 1, 0);  // kBlackBitPattern.
+}
+
+
+void MacroAssembler::JumpIfDictionaryInPrototypeChain(
+    Register object,
+    Register scratch0,
+    Register scratch1,
+    Label* found) {
+  ASSERT(!AreAliased(object, scratch0, scratch1));
+  Factory* factory = isolate()->factory();
+  Register current = scratch0;
+  Label loop_again;
+
+  // Scratch contains elements pointer.
+  Mov(current, object);
+
+  // Loop based on the map going up the prototype chain.
+  Bind(&loop_again);
+  Ldr(current, FieldMemOperand(current, HeapObject::kMapOffset));
+  Ldrb(scratch1, FieldMemOperand(current, Map::kBitField2Offset));
+  Ubfx(scratch1, scratch1, Map::kElementsKindShift, Map::kElementsKindBitCount);
+  CompareAndBranch(scratch1, DICTIONARY_ELEMENTS, eq, found);
+  Ldr(current, FieldMemOperand(current, Map::kPrototypeOffset));
+  CompareAndBranch(current, Operand(factory->null_value()), ne, &loop_again);
+}
+
+
+void MacroAssembler::GetRelocatedValueLocation(Register ldr_location,
+                                               Register result) {
+  ASSERT(!result.Is(ldr_location));
+  const uint32_t kLdrLitOffset_lsb = 5;
+  const uint32_t kLdrLitOffset_width = 19;
+  Ldr(result, MemOperand(ldr_location));
+  if (emit_debug_code()) {
+    And(result, result, LoadLiteralFMask);
+    Cmp(result, LoadLiteralFixed);
+    Check(eq, kTheInstructionToPatchShouldBeAnLdrLiteral);
+    // The instruction was clobbered. Reload it.
+    Ldr(result, MemOperand(ldr_location));
+  }
+  Sbfx(result, result, kLdrLitOffset_lsb, kLdrLitOffset_width);
+  Add(result, ldr_location, Operand(result, LSL, kWordSizeInBytesLog2));
+}
+
+
+void MacroAssembler::EnsureNotWhite(
+    Register value,
+    Register bitmap_scratch,
+    Register shift_scratch,
+    Register load_scratch,
+    Register length_scratch,
+    Label* value_is_white_and_not_data) {
+  ASSERT(!AreAliased(
+      value, bitmap_scratch, shift_scratch, load_scratch, length_scratch));
+
+  // These bit sequences are backwards. The first character in the string
+  // represents the least significant bit.
+  ASSERT(strcmp(Marking::kWhiteBitPattern, "00") == 0);
+  ASSERT(strcmp(Marking::kBlackBitPattern, "10") == 0);
+  ASSERT(strcmp(Marking::kGreyBitPattern, "11") == 0);
+
+  GetMarkBits(value, bitmap_scratch, shift_scratch);
+  Ldr(load_scratch, MemOperand(bitmap_scratch, MemoryChunk::kHeaderSize));
+  Lsr(load_scratch, load_scratch, shift_scratch);
+
+  AssertHasValidColor(load_scratch);
+
+  // If the value is black or grey we don't need to do anything.
+  // Since both black and grey have a 1 in the first position and white does
+  // not have a 1 there we only need to check one bit.
+  Label done;
+  Tbnz(load_scratch, 0, &done);
+
+  // Value is white.  We check whether it is data that doesn't need scanning.
+  Register map = load_scratch;  // Holds map while checking type.
+  Label is_data_object;
+
+  // Check for heap-number.
+  Ldr(map, FieldMemOperand(value, HeapObject::kMapOffset));
+  Mov(length_scratch, HeapNumber::kSize);
+  JumpIfRoot(map, Heap::kHeapNumberMapRootIndex, &is_data_object);
+
+  // Check for strings.
+  ASSERT(kIsIndirectStringTag == 1 && kIsIndirectStringMask == 1);
+  ASSERT(kNotStringTag == 0x80 && kIsNotStringMask == 0x80);
+  // If it's a string and it's not a cons string then it's an object containing
+  // no GC pointers.
+  Register instance_type = load_scratch;
+  Ldrb(instance_type, FieldMemOperand(map, Map::kInstanceTypeOffset));
+  TestAndBranchIfAnySet(instance_type,
+                        kIsIndirectStringMask | kIsNotStringMask,
+                        value_is_white_and_not_data);
+
+  // It's a non-indirect (non-cons and non-slice) string.
+  // If it's external, the length is just ExternalString::kSize.
+  // Otherwise it's String::kHeaderSize + string->length() * (1 or 2).
+  // External strings are the only ones with the kExternalStringTag bit
+  // set.
+  ASSERT_EQ(0, kSeqStringTag & kExternalStringTag);
+  ASSERT_EQ(0, kConsStringTag & kExternalStringTag);
+  Mov(length_scratch, ExternalString::kSize);
+  TestAndBranchIfAnySet(instance_type, kExternalStringTag, &is_data_object);
+
+  // Sequential string, either ASCII or UC16.
+  // For ASCII (char-size of 1) we shift the smi tag away to get the length.
+  // For UC16 (char-size of 2) we just leave the smi tag in place, thereby
+  // getting the length multiplied by 2.
+  ASSERT(kOneByteStringTag == 4 && kStringEncodingMask == 4);
+  Ldrsw(length_scratch, UntagSmiFieldMemOperand(value,
+                                                String::kLengthOffset));
+  Tst(instance_type, kStringEncodingMask);
+  Cset(load_scratch, eq);
+  Lsl(length_scratch, length_scratch, load_scratch);
+  Add(length_scratch,
+      length_scratch,
+      SeqString::kHeaderSize + kObjectAlignmentMask);
+  Bic(length_scratch, length_scratch, kObjectAlignmentMask);
+
+  Bind(&is_data_object);
+  // Value is a data object, and it is white.  Mark it black.  Since we know
+  // that the object is white we can make it black by flipping one bit.
+  Register mask = shift_scratch;
+  Mov(load_scratch, 1);
+  Lsl(mask, load_scratch, shift_scratch);
+
+  Ldr(load_scratch, MemOperand(bitmap_scratch, MemoryChunk::kHeaderSize));
+  Orr(load_scratch, load_scratch, mask);
+  Str(load_scratch, MemOperand(bitmap_scratch, MemoryChunk::kHeaderSize));
+
+  Bic(bitmap_scratch, bitmap_scratch, Page::kPageAlignmentMask);
+  Ldr(load_scratch, MemOperand(bitmap_scratch, MemoryChunk::kLiveBytesOffset));
+  Add(load_scratch, load_scratch, length_scratch);
+  Str(load_scratch, MemOperand(bitmap_scratch, MemoryChunk::kLiveBytesOffset));
+
+  Bind(&done);
+}
+
+
+void MacroAssembler::Assert(Condition cond, BailoutReason reason) {
+  if (emit_debug_code()) {
+    Check(cond, reason);
+  }
+}
+
+
+
+void MacroAssembler::AssertRegisterIsClear(Register reg, BailoutReason reason) {
+  if (emit_debug_code()) {
+    CheckRegisterIsClear(reg, reason);
+  }
+}
+
+
+void MacroAssembler::AssertRegisterIsRoot(Register reg,
+                                          Heap::RootListIndex index,
+                                          BailoutReason reason) {
+  // CompareRoot uses Tmp0().
+  ASSERT(!reg.Is(Tmp0()));
+  if (emit_debug_code()) {
+    CompareRoot(reg, index);
+    Check(eq, reason);
+  }
+}
+
+
+void MacroAssembler::AssertFastElements(Register elements) {
+  if (emit_debug_code()) {
+    Register temp = Tmp1();
+    Label ok;
+    Ldr(temp, FieldMemOperand(elements, HeapObject::kMapOffset));
+    JumpIfRoot(temp, Heap::kFixedArrayMapRootIndex, &ok);
+    JumpIfRoot(temp, Heap::kFixedDoubleArrayMapRootIndex, &ok);
+    JumpIfRoot(temp, Heap::kFixedCOWArrayMapRootIndex, &ok);
+    Abort(kJSObjectWithFastElementsMapHasSlowElements);
+    Bind(&ok);
+  }
+}
+
+
+void MacroAssembler::AssertIsString(const Register& object) {
+  if (emit_debug_code()) {
+    Register temp = Tmp1();
+    STATIC_ASSERT(kSmiTag == 0);
+    Tst(object, Operand(kSmiTagMask));
+    Check(ne, kOperandIsNotAString);
+    Ldr(temp, FieldMemOperand(object, HeapObject::kMapOffset));
+    CompareInstanceType(temp, temp, FIRST_NONSTRING_TYPE);
+    Check(lo, kOperandIsNotAString);
+  }
+}
+
+
+void MacroAssembler::Check(Condition cond, BailoutReason reason) {
+  Label ok;
+  B(cond, &ok);
+  Abort(reason);
+  // Will not return here.
+  Bind(&ok);
+}
+
+
+void MacroAssembler::CheckRegisterIsClear(Register reg, BailoutReason reason) {
+  Label ok;
+  Cbz(reg, &ok);
+  Abort(reason);
+  // Will not return here.
+  Bind(&ok);
+}
+
+
+void MacroAssembler::Abort(BailoutReason reason) {
+#ifdef DEBUG
+  RecordComment("Abort message: ");
+  RecordComment(GetBailoutReason(reason));
+
+  if (FLAG_trap_on_abort) {
+    Brk(0);
+    return;
+  }
+#endif
+
+  Label msg_address;
+  Adr(x0, &msg_address);
+
+  if (use_real_aborts()) {
+    // Split the message pointer into two SMI to avoid the GC
+    // trying to scan the string.
+    STATIC_ASSERT((kSmiShift == 32) && (kSmiTag == 0));
+    SmiTag(x1, x0);
+    Bic(x0, x0, kSmiShiftMask);
+
+    Push(x0, x1);
+
+    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);
+      CallRuntime(Runtime::kAbort, 2);
+    } else {
+      CallRuntime(Runtime::kAbort, 2);
+    }
+  } else {
+    // Call Printf directly, to report the error. The message is in x0, which is
+    // the first argument to Printf.
+    if (!csp.Is(StackPointer())) {
+      Bic(csp, StackPointer(), 0xf);
+    }
+    CallPrintf();
+
+    // The CallPrintf will return, so this point is actually reachable in this
+    // context. However:
+    //   - We're already executing an abort (which shouldn't be reachable in
+    //     valid code).
+    //   - We need a way to stop execution on both the simulator and real
+    //     hardware, and Unreachable() is the best option.
+    Unreachable();
+  }
+
+  // Emit the message string directly in the instruction stream.
+  {
+    BlockConstPoolScope scope(this);
+    Bind(&msg_address);
+    // TODO(jbramley): Since the reason is an enum, why do we still encode the
+    // string (and a pointer to it) in the instruction stream?
+    EmitStringData(GetBailoutReason(reason));
+  }
+}
+
+
+void MacroAssembler::LoadTransitionedArrayMapConditional(
+    ElementsKind expected_kind,
+    ElementsKind transitioned_kind,
+    Register map_in_out,
+    Register scratch,
+    Label* no_map_match) {
+  // Load the global or builtins object from the current context.
+  Ldr(scratch, GlobalObjectMemOperand());
+  Ldr(scratch, FieldMemOperand(scratch, GlobalObject::kNativeContextOffset));
+
+  // Check that the function's map is the same as the expected cached map.
+  Ldr(scratch, ContextMemOperand(scratch, Context::JS_ARRAY_MAPS_INDEX));
+  size_t offset = (expected_kind * kPointerSize) + FixedArrayBase::kHeaderSize;
+  Ldr(Tmp0(), FieldMemOperand(scratch, offset));
+  Cmp(map_in_out, Tmp0());
+  B(ne, no_map_match);
+
+  // Use the transitioned cached map.
+  offset = (transitioned_kind * kPointerSize) + FixedArrayBase::kHeaderSize;
+  Ldr(map_in_out, FieldMemOperand(scratch, offset));
+}
+
+
+void MacroAssembler::LoadInitialArrayMap(Register function_in,
+                                         Register scratch,
+                                         Register map_out,
+                                         ArrayHasHoles holes) {
+  ASSERT(!AreAliased(function_in, scratch, map_out));
+  Label done;
+  Ldr(map_out, FieldMemOperand(function_in,
+                               JSFunction::kPrototypeOrInitialMapOffset));
+
+  if (!FLAG_smi_only_arrays) {
+    ElementsKind kind = (holes == kArrayCanHaveHoles) ? FAST_HOLEY_ELEMENTS
+                                                      : FAST_ELEMENTS;
+    LoadTransitionedArrayMapConditional(FAST_SMI_ELEMENTS, kind, map_out,
+                                        scratch, &done);
+  } else if (holes == kArrayCanHaveHoles) {
+    LoadTransitionedArrayMapConditional(FAST_SMI_ELEMENTS,
+                                        FAST_HOLEY_SMI_ELEMENTS, map_out,
+                                        scratch, &done);
+  }
+  Bind(&done);
+}
+
+
+void MacroAssembler::LoadArrayFunction(Register function) {
+  // Load the global or builtins object from the current context.
+  Ldr(function, GlobalObjectMemOperand());
+  // Load the global context from the global or builtins object.
+  Ldr(function,
+      FieldMemOperand(function, GlobalObject::kGlobalContextOffset));
+  // Load the array function from the native context.
+  Ldr(function, ContextMemOperand(function, Context::ARRAY_FUNCTION_INDEX));
+}
+
+
+void MacroAssembler::LoadGlobalFunction(int index, Register function) {
+  // Load the global or builtins object from the current context.
+  Ldr(function, GlobalObjectMemOperand());
+  // Load the native context from the global or builtins object.
+  Ldr(function, FieldMemOperand(function,
+                                GlobalObject::kNativeContextOffset));
+  // Load the function from the native context.
+  Ldr(function, ContextMemOperand(function, index));
+}
+
+
+void MacroAssembler::LoadGlobalFunctionInitialMap(Register function,
+                                                  Register map,
+                                                  Register scratch) {
+  // Load the initial map. The global functions all have initial maps.
+  Ldr(map, FieldMemOperand(function, JSFunction::kPrototypeOrInitialMapOffset));
+  if (emit_debug_code()) {
+    Label ok, fail;
+    CheckMap(map, scratch, Heap::kMetaMapRootIndex, &fail, DO_SMI_CHECK);
+    B(&ok);
+    Bind(&fail);
+    Abort(kGlobalFunctionsMustHaveInitialMap);
+    Bind(&ok);
+  }
+}
+
+
+// This is the main Printf implementation. All other Printf variants call
+// PrintfNoPreserve after setting up one or more PreserveRegisterScopes.
+void MacroAssembler::PrintfNoPreserve(const char * format,
+                                      const CPURegister& arg0,
+                                      const CPURegister& arg1,
+                                      const CPURegister& arg2,
+                                      const CPURegister& arg3) {
+  // We cannot handle a caller-saved stack pointer. It doesn't make much sense
+  // in most cases anyway, so this restriction shouldn't be too serious.
+  ASSERT(!kCallerSaved.IncludesAliasOf(__ StackPointer()));
+
+  // We cannot print Tmp0() or Tmp1() as they're used internally by the macro
+  // assembler. We cannot print the stack pointer because it is typically used
+  // to preserve caller-saved registers (using other Printf variants which
+  // depend on this helper).
+  ASSERT(!AreAliased(Tmp0(), Tmp1(), StackPointer(), arg0));
+  ASSERT(!AreAliased(Tmp0(), Tmp1(), StackPointer(), arg1));
+  ASSERT(!AreAliased(Tmp0(), Tmp1(), StackPointer(), arg2));
+  ASSERT(!AreAliased(Tmp0(), Tmp1(), StackPointer(), arg3));
+
+  static const int kMaxArgCount = 4;
+  // Assume that we have the maximum number of arguments until we know
+  // otherwise.
+  int arg_count = kMaxArgCount;
+
+  // The provided arguments.
+  CPURegister args[kMaxArgCount] = {arg0, arg1, arg2, arg3};
+
+  // The PCS registers where the arguments need to end up.
+  CPURegister pcs[kMaxArgCount] = {NoCPUReg, NoCPUReg, NoCPUReg, NoCPUReg};
+
+  // Promote FP arguments to doubles, and integer arguments to X registers.
+  // Note that FP and integer arguments cannot be mixed, but we'll check
+  // AreSameSizeAndType once we've processed these promotions.
+  for (int i = 0; i < kMaxArgCount; i++) {
+    if (args[i].IsRegister()) {
+      // Note that we use x1 onwards, because x0 will hold the format string.
+      pcs[i] = Register::XRegFromCode(i + 1);
+      // For simplicity, we handle all integer arguments as X registers. An X
+      // register argument takes the same space as a W register argument in the
+      // PCS anyway. The only limitation is that we must explicitly clear the
+      // top word for W register arguments as the callee will expect it to be
+      // clear.
+      if (!args[i].Is64Bits()) {
+        const Register& as_x = args[i].X();
+        And(as_x, as_x, 0x00000000ffffffff);
+        args[i] = as_x;
+      }
+    } else if (args[i].IsFPRegister()) {
+      pcs[i] = FPRegister::DRegFromCode(i);
+      // C and C++ varargs functions (such as printf) implicitly promote float
+      // arguments to doubles.
+      if (!args[i].Is64Bits()) {
+        FPRegister s(args[i]);
+        const FPRegister& as_d = args[i].D();
+        Fcvt(as_d, s);
+        args[i] = as_d;
+      }
+    } else {
+      // This is the first empty (NoCPUReg) argument, so use it to set the
+      // argument count and bail out.
+      arg_count = i;
+      break;
+    }
+  }
+  ASSERT((arg_count >= 0) && (arg_count <= kMaxArgCount));
+  // Check that every remaining argument is NoCPUReg.
+  for (int i = arg_count; i < kMaxArgCount; i++) {
+    ASSERT(args[i].IsNone());
+  }
+  ASSERT((arg_count == 0) || AreSameSizeAndType(args[0], args[1],
+                                                args[2], args[3],
+                                                pcs[0], pcs[1],
+                                                pcs[2], pcs[3]));
+
+  // Move the arguments into the appropriate PCS registers.
+  //
+  // Arranging an arbitrary list of registers into x1-x4 (or d0-d3) is
+  // surprisingly complicated.
+  //
+  //  * For even numbers of registers, we push the arguments and then pop them
+  //    into their final registers. This maintains 16-byte stack alignment in
+  //    case csp is the stack pointer, since we're only handling X or D
+  //    registers at this point.
+  //
+  //  * For odd numbers of registers, we push and pop all but one register in
+  //    the same way, but the left-over register is moved directly, since we
+  //    can always safely move one register without clobbering any source.
+  if (arg_count >= 4) {
+    Push(args[3], args[2], args[1], args[0]);
+  } else if (arg_count >= 2) {
+    Push(args[1], args[0]);
+  }
+
+  if ((arg_count % 2) != 0) {
+    // Move the left-over register directly.
+    const CPURegister& leftover_arg = args[arg_count - 1];
+    const CPURegister& leftover_pcs = pcs[arg_count - 1];
+    if (leftover_arg.IsRegister()) {
+      Mov(Register(leftover_pcs), Register(leftover_arg));
+    } else {
+      Fmov(FPRegister(leftover_pcs), FPRegister(leftover_arg));
+    }
+  }
+
+  if (arg_count >= 4) {
+    Pop(pcs[0], pcs[1], pcs[2], pcs[3]);
+  } else if (arg_count >= 2) {
+    Pop(pcs[0], pcs[1]);
+  }
+
+  // Load the format string into x0, as per the procedure-call standard.
+  //
+  // To make the code as portable as possible, the format string is encoded
+  // directly in the instruction stream. It might be cleaner to encode it in a
+  // literal pool, but since Printf is usually used for debugging, it is
+  // beneficial for it to be minimally dependent on other features.
+  Label format_address;
+  Adr(x0, &format_address);
+
+  // Emit the format string directly in the instruction stream.
+  { BlockConstPoolScope scope(this);
+    Label after_data;
+    B(&after_data);
+    Bind(&format_address);
+    EmitStringData(format);
+    Unreachable();
+    Bind(&after_data);
+  }
+
+  // We don't pass any arguments on the stack, but we still need to align the C
+  // stack pointer to a 16-byte boundary for PCS compliance.
+  if (!csp.Is(StackPointer())) {
+    Bic(csp, StackPointer(), 0xf);
+  }
+
+  CallPrintf(pcs[0].type());
+}
+
+
+void MacroAssembler::CallPrintf(CPURegister::RegisterType type) {
+  // A call to printf needs special handling for the simulator, since the system
+  // printf function will use a different instruction set and the procedure-call
+  // standard will not be compatible.
+#ifdef USE_SIMULATOR
+  { InstructionAccurateScope scope(this, kPrintfLength / kInstructionSize);
+    hlt(kImmExceptionIsPrintf);
+    dc32(type);
+  }
+#else
+  Call(FUNCTION_ADDR(printf), RelocInfo::EXTERNAL_REFERENCE);
+#endif
+}
+
+
+void MacroAssembler::Printf(const char * format,
+                            const CPURegister& arg0,
+                            const CPURegister& arg1,
+                            const CPURegister& arg2,
+                            const CPURegister& arg3) {
+  // Preserve all caller-saved registers as well as NZCV.
+  // If csp is the stack pointer, PushCPURegList asserts that the size of each
+  // list is a multiple of 16 bytes.
+  PushCPURegList(kCallerSaved);
+  PushCPURegList(kCallerSavedFP);
+  // Use Tmp0() as a scratch register. It is not accepted by Printf so it will
+  // never overlap an argument register.
+  Mrs(Tmp0(), NZCV);
+  Push(Tmp0(), xzr);
+
+  PrintfNoPreserve(format, arg0, arg1, arg2, arg3);
+
+  Pop(xzr, Tmp0());
+  Msr(NZCV, Tmp0());
+  PopCPURegList(kCallerSavedFP);
+  PopCPURegList(kCallerSaved);
+}
+
+
+void MacroAssembler::EmitFrameSetupForCodeAgePatching() {
+  // TODO(jbramley): Other architectures use the internal memcpy to copy the
+  // sequence. If this is a performance bottleneck, we should consider caching
+  // the sequence and copying it in the same way.
+  InstructionAccurateScope scope(this, kCodeAgeSequenceSize / kInstructionSize);
+  ASSERT(jssp.Is(StackPointer()));
+  EmitFrameSetupForCodeAgePatching(this);
+}
+
+
+
+void MacroAssembler::EmitCodeAgeSequence(Code* stub) {
+  InstructionAccurateScope scope(this, kCodeAgeSequenceSize / kInstructionSize);
+  ASSERT(jssp.Is(StackPointer()));
+  EmitCodeAgeSequence(this, stub);
+}
+
+
+#undef __
+#define __ assm->
+
+
+void MacroAssembler::EmitFrameSetupForCodeAgePatching(Assembler * assm) {
+  Label start;
+  __ bind(&start);
+
+  // We can do this sequence using four instructions, but the code ageing
+  // sequence that patches it needs five, so we use the extra space to try to
+  // simplify some addressing modes and remove some dependencies (compared to
+  // using two stp instructions with write-back).
+  __ sub(jssp, jssp, 4 * kXRegSizeInBytes);
+  __ sub(csp, csp, 4 * kXRegSizeInBytes);
+  __ stp(x1, cp, MemOperand(jssp, 0 * kXRegSizeInBytes));
+  __ stp(fp, lr, MemOperand(jssp, 2 * kXRegSizeInBytes));
+  __ add(fp, jssp, StandardFrameConstants::kFixedFrameSizeFromFp);
+
+  __ AssertSizeOfCodeGeneratedSince(&start, kCodeAgeSequenceSize);
+}
+
+
+void MacroAssembler::EmitCodeAgeSequence(Assembler * assm,
+                                         Code * stub) {
+  Label start;
+  __ bind(&start);
+  // When the stub is called, the sequence is replaced with the young sequence
+  // (as in EmitFrameSetupForCodeAgePatching). After the code is replaced, the
+  // stub jumps to &start, stored in x0. The young sequence does not call the
+  // stub so there is no infinite loop here.
+  //
+  // A branch (br) is used rather than a call (blr) because this code replaces
+  // the frame setup code that would normally preserve lr.
+  __ LoadLiteral(ip0, kCodeAgeStubEntryOffset);
+  __ adr(x0, &start);
+  __ br(ip0);
+  // IsCodeAgeSequence in codegen-a64.cc assumes that the code generated up
+  // until now (kCodeAgeStubEntryOffset) is the same for all code age sequences.
+  __ AssertSizeOfCodeGeneratedSince(&start, kCodeAgeStubEntryOffset);
+  if (stub) {
+    __ dc64(reinterpret_cast<uint64_t>(stub->instruction_start()));
+    __ AssertSizeOfCodeGeneratedSince(&start, kCodeAgeSequenceSize);
+  }
+}
+
+
+bool MacroAssembler::IsYoungSequence(byte* sequence) {
+  // Generate a young sequence to compare with.
+  const int length = kCodeAgeSequenceSize / kInstructionSize;
+  static bool initialized = false;
+  static byte young[kCodeAgeSequenceSize];
+  if (!initialized) {
+    PatchingAssembler patcher(young, length);
+    // The young sequence is the frame setup code for FUNCTION code types. It is
+    // generated by FullCodeGenerator::Generate.
+    MacroAssembler::EmitFrameSetupForCodeAgePatching(&patcher);
+    initialized = true;
+  }
+
+  bool is_young = (memcmp(sequence, young, kCodeAgeSequenceSize) == 0);
+  ASSERT(is_young || IsCodeAgeSequence(sequence));
+  return is_young;
+}
+
+
+#ifdef DEBUG
+bool MacroAssembler::IsCodeAgeSequence(byte* sequence) {
+  // The old sequence varies depending on the code age. However, the code up
+  // until kCodeAgeStubEntryOffset does not change, so we can check that part to
+  // get a reasonable level of verification.
+  const int length = kCodeAgeStubEntryOffset / kInstructionSize;
+  static bool initialized = false;
+  static byte old[kCodeAgeStubEntryOffset];
+  if (!initialized) {
+    PatchingAssembler patcher(old, length);
+    MacroAssembler::EmitCodeAgeSequence(&patcher, NULL);
+    initialized = true;
+  }
+  return memcmp(sequence, old, kCodeAgeStubEntryOffset) == 0;
+}
+#endif
+
+
+#undef __
+#define __ masm->
+
+
+void InlineSmiCheckInfo::Emit(MacroAssembler* masm, const Register& reg,
+                              const Label* smi_check) {
+  Assembler::BlockConstPoolScope scope(masm);
+  if (reg.IsValid()) {
+    ASSERT(smi_check->is_bound());
+    ASSERT(reg.Is64Bits());
+
+    // Encode the register (x0-x30) in the lowest 5 bits, then the offset to
+    // 'check' in the other bits. The possible offset is limited in that we
+    // use BitField to pack the data, and the underlying data type is a
+    // uint32_t.
+    uint32_t delta = __ InstructionsGeneratedSince(smi_check);
+    __ InlineData(RegisterBits::encode(reg.code()) | DeltaBits::encode(delta));
+  } else {
+    ASSERT(!smi_check->is_bound());
+
+    // An offset of 0 indicates that there is no patch site.
+    __ InlineData(0);
+  }
+}
+
+
+InlineSmiCheckInfo::InlineSmiCheckInfo(Address info)
+    : reg_(NoReg), smi_check_(NULL) {
+  InstructionSequence* inline_data = InstructionSequence::At(info);
+  ASSERT(inline_data->IsInlineData());
+  if (inline_data->IsInlineData()) {
+    uint64_t payload = inline_data->InlineData();
+    // We use BitField to decode the payload, and BitField can only handle
+    // 32-bit values.
+    ASSERT(is_uint32(payload));
+    if (payload != 0) {
+      int reg_code = RegisterBits::decode(payload);
+      reg_ = Register::XRegFromCode(reg_code);
+      uint64_t smi_check_delta = DeltaBits::decode(payload);
+      ASSERT(smi_check_delta != 0);
+      smi_check_ = inline_data - (smi_check_delta * kInstructionSize);
+    }
+  }
+}
+
+
+#undef __
+
+
+} }  // namespace v8::internal
+
+#endif  // V8_TARGET_ARCH_A64