Contribution of PowerPC port.

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

+// Copyright 2012 the V8 project authors. All rights reserved.
+//
+// Copyright IBM Corp. 2012, 2013. All rights reserved.
+//
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "src/v8.h"
+
+#if V8_TARGET_ARCH_PPC
+
+#include "src/code-stubs.h"
+#include "src/cpu-profiler.h"
+#include "src/log.h"
+#include "src/macro-assembler.h"
+#include "src/regexp-macro-assembler.h"
+#include "src/regexp-stack.h"
+#include "src/unicode.h"
+
+#include "src/ppc/regexp-macro-assembler-ppc.h"
+
+namespace v8 {
+namespace internal {
+
+#ifndef V8_INTERPRETED_REGEXP
+/*
+ * This assembler uses the following register assignment convention
+ * - r25: Temporarily stores the index of capture start after a matching pass
+ *        for a global regexp.
+ * - r26: Pointer to current code object (Code*) including heap object tag.
+ * - r27: Current position in input, as negative offset from end of string.
+ *        Please notice that this is the byte offset, not the character offset!
+ * - r28: Currently loaded character. Must be loaded using
+ *        LoadCurrentCharacter before using any of the dispatch methods.
+ * - r29: Points to tip of backtrack stack
+ * - r30: End of input (points to byte after last character in input).
+ * - r31: Frame pointer. Used to access arguments, local variables and
+ *         RegExp registers.
+ * - r12: IP register, used by assembler. Very volatile.
+ * - r1/sp : Points to tip of C stack.
+ *
+ * The remaining registers are free for computations.
+ * Each call to a public method should retain this convention.
+ *
+ * The stack will have the following structure:
+ *  - fp[44]  Isolate* isolate   (address of the current isolate)
+ *  - fp[40]  secondary link/return address used by native call.
+ *  - fp[36]  lr save area (currently unused)
+ *  - fp[32]  backchain    (currently unused)
+ *  --- sp when called ---
+ *  - fp[28]  return address     (lr).
+ *  - fp[24]  old frame pointer  (r31).
+ *  - fp[0..20]  backup of registers r25..r30
+ *  --- frame pointer ----
+ *  - fp[-4]  direct_call        (if 1, direct call from JavaScript code,
+ *                                if 0, call through the runtime system).
+ *  - fp[-8]  stack_area_base    (high end of the memory area to use as
+ *                                backtracking stack).
+ *  - fp[-12] capture array size (may fit multiple sets of matches)
+ *  - fp[-16] int* capture_array (int[num_saved_registers_], for output).
+ *  - fp[-20] end of input       (address of end of string).
+ *  - fp[-24] start of input     (address of first character in string).
+ *  - fp[-28] start index        (character index of start).
+ *  - fp[-32] void* input_string (location of a handle containing the string).
+ *  - fp[-36] success counter    (only for global regexps to count matches).
+ *  - fp[-40] Offset of location before start of input (effectively character
+ *            position -1). Used to initialize capture registers to a
+ *            non-position.
+ *  - fp[-44] At start (if 1, we are starting at the start of the
+ *    string, otherwise 0)
+ *  - fp[-48] register 0         (Only positions must be stored in the first
+ *  -         register 1          num_saved_registers_ registers)
+ *  -         ...
+ *  -         register num_registers-1
+ *  --- sp ---
+ *
+ * The first num_saved_registers_ registers are initialized to point to
+ * "character -1" in the string (i.e., char_size() bytes before the first
+ * character of the string). The remaining registers start out as garbage.
+ *
+ * The data up to the return address must be placed there by the calling
+ * code and the remaining arguments are passed in registers, e.g. by calling the
+ * code entry as cast to a function with the signature:
+ * int (*match)(String* input_string,
+ *              int start_index,
+ *              Address start,
+ *              Address end,
+ *              int* capture_output_array,
+ *              byte* stack_area_base,
+ *              Address secondary_return_address,  // Only used by native call.
+ *              bool direct_call = false)
+ * The call is performed by NativeRegExpMacroAssembler::Execute()
+ * (in regexp-macro-assembler.cc) via the CALL_GENERATED_REGEXP_CODE macro
+ * in ppc/simulator-ppc.h.
+ * When calling as a non-direct call (i.e., from C++ code), the return address
+ * area is overwritten with the LR register by the RegExp code. When doing a
+ * direct call from generated code, the return address is placed there by
+ * the calling code, as in a normal exit frame.
+ */
+
+#define __ ACCESS_MASM(masm_)
+
+RegExpMacroAssemblerPPC::RegExpMacroAssemblerPPC(
+    Mode mode,
+    int registers_to_save,
+    Zone* zone)
+    : NativeRegExpMacroAssembler(zone),
+      masm_(new MacroAssembler(zone->isolate(), NULL, kRegExpCodeSize)),
+      mode_(mode),
+      num_registers_(registers_to_save),
+      num_saved_registers_(registers_to_save),
+      entry_label_(),
+      start_label_(),
+      success_label_(),
+      backtrack_label_(),
+      exit_label_(),
+      internal_failure_label_() {
+  DCHECK_EQ(0, registers_to_save % 2);
+
+  // Called from C
+#if ABI_USES_FUNCTION_DESCRIPTORS
+  __ function_descriptor();
+#endif
+
+  __ b(&entry_label_);   // We'll write the entry code later.
+  // If the code gets too big or corrupted, an internal exception will be
+  // raised, and we will exit right away.
+  __ bind(&internal_failure_label_);
+  __ li(r3, Operand(FAILURE));
+  __ Ret();
+  __ bind(&start_label_);  // And then continue from here.
+}
+
+
+RegExpMacroAssemblerPPC::~RegExpMacroAssemblerPPC() {
+  delete masm_;
+  // Unuse labels in case we throw away the assembler without calling GetCode.
+  entry_label_.Unuse();
+  start_label_.Unuse();
+  success_label_.Unuse();
+  backtrack_label_.Unuse();
+  exit_label_.Unuse();
+  check_preempt_label_.Unuse();
+  stack_overflow_label_.Unuse();
+  internal_failure_label_.Unuse();
+}
+
+
+int RegExpMacroAssemblerPPC::stack_limit_slack()  {
+  return RegExpStack::kStackLimitSlack;
+}
+
+
+void RegExpMacroAssemblerPPC::AdvanceCurrentPosition(int by) {
+  if (by != 0) {
+    __ addi(current_input_offset(),
+            current_input_offset(), Operand(by * char_size()));
+  }
+}
+
+
+void RegExpMacroAssemblerPPC::AdvanceRegister(int reg, int by) {
+  DCHECK(reg >= 0);
+  DCHECK(reg < num_registers_);
+  if (by != 0) {
+    __ LoadP(r3, register_location(reg), r0);
+    __ mov(r0, Operand(by));
+    __ add(r3, r3, r0);
+    __ StoreP(r3, register_location(reg), r0);
+  }
+}
+
+
+void RegExpMacroAssemblerPPC::Backtrack() {
+  CheckPreemption();
+  // Pop Code* offset from backtrack stack, add Code* and jump to location.
+  Pop(r3);
+  __ add(r3, r3, code_pointer());
+  __ mtctr(r3);
+  __ bctr();
+}
+
+
+void RegExpMacroAssemblerPPC::Bind(Label* label) {
+  __ bind(label);
+}
+
+
+void RegExpMacroAssemblerPPC::CheckCharacter(uint32_t c, Label* on_equal) {
+  __ Cmpli(current_character(), Operand(c), r0);
+  BranchOrBacktrack(eq, on_equal);
+}
+
+
+void RegExpMacroAssemblerPPC::CheckCharacterGT(uc16 limit, Label* on_greater) {
+  __ Cmpli(current_character(), Operand(limit), r0);
+  BranchOrBacktrack(gt, on_greater);
+}
+
+
+void RegExpMacroAssemblerPPC::CheckAtStart(Label* on_at_start) {
+  Label not_at_start;
+  // Did we start the match at the start of the string at all?
+  __ LoadP(r3, MemOperand(frame_pointer(), kStartIndex));
+  __ cmpi(r3, Operand::Zero());
+  BranchOrBacktrack(ne, &not_at_start);
+
+  // If we did, are we still at the start of the input?
+  __ LoadP(r4, MemOperand(frame_pointer(), kInputStart));
+  __ mr(r0, current_input_offset());
+  __ add(r3, end_of_input_address(), r0);
+  __ cmp(r4, r3);
+  BranchOrBacktrack(eq, on_at_start);
+  __ bind(&not_at_start);
+}
+
+
+void RegExpMacroAssemblerPPC::CheckNotAtStart(Label* on_not_at_start) {
+  // Did we start the match at the start of the string at all?
+  __ LoadP(r3, MemOperand(frame_pointer(), kStartIndex));
+  __ cmpi(r3, Operand::Zero());
+  BranchOrBacktrack(ne, on_not_at_start);
+  // If we did, are we still at the start of the input?
+  __ LoadP(r4, MemOperand(frame_pointer(), kInputStart));
+  __ add(r3, end_of_input_address(), current_input_offset());
+  __ cmp(r3, r4);
+  BranchOrBacktrack(ne, on_not_at_start);
+}
+
+
+void RegExpMacroAssemblerPPC::CheckCharacterLT(uc16 limit, Label* on_less) {
+  __ Cmpli(current_character(), Operand(limit), r0);
+  BranchOrBacktrack(lt, on_less);
+}
+
+
+void RegExpMacroAssemblerPPC::CheckGreedyLoop(Label* on_equal) {
+  Label backtrack_non_equal;
+  __ LoadP(r3, MemOperand(backtrack_stackpointer(), 0));
+  __ cmp(current_input_offset(), r3);
+  __ bne(&backtrack_non_equal);
+  __ addi(backtrack_stackpointer(),
+         backtrack_stackpointer(), Operand(kPointerSize));
+
+  __ bind(&backtrack_non_equal);
+  BranchOrBacktrack(eq, on_equal);
+}
+
+
+void RegExpMacroAssemblerPPC::CheckNotBackReferenceIgnoreCase(
+    int start_reg,
+    Label* on_no_match) {
+  Label fallthrough;
+  __ LoadP(r3, register_location(start_reg), r0);  // Index of start of capture
+  __ LoadP(r4, register_location(start_reg + 1), r0);  // Index of end
+  __ sub(r4, r4, r3, LeaveOE, SetRC);  // Length of capture.
+
+  // If length is zero, either the capture is empty or it is not participating.
+  // In either case succeed immediately.
+  __ beq(&fallthrough, cr0);
+
+  // Check that there are enough characters left in the input.
+  __ add(r0, r4, current_input_offset(), LeaveOE, SetRC);
+//  __ cmn(r1, Operand(current_input_offset()));
+  BranchOrBacktrack(gt, on_no_match, cr0);
+
+  if (mode_ == ASCII) {
+    Label success;
+    Label fail;
+    Label loop_check;
+
+    // r3 - offset of start of capture
+    // r4 - length of capture
+    __ add(r3, r3, end_of_input_address());
+    __ add(r5, end_of_input_address(), current_input_offset());
+    __ add(r4, r3, r4);
+
+    // r3 - Address of start of capture.
+    // r4 - Address of end of capture
+    // r5 - Address of current input position.
+
+    Label loop;
+    __ bind(&loop);
+    __ lbz(r6, MemOperand(r3));
+    __ addi(r3, r3, Operand(char_size()));
+    __ lbz(r25, MemOperand(r5));
+    __ addi(r5, r5, Operand(char_size()));
+    __ cmp(r25, r6);
+    __ beq(&loop_check);
+
+    // Mismatch, try case-insensitive match (converting letters to lower-case).
+    __ ori(r6, r6, Operand(0x20));  // Convert capture character to lower-case.
+    __ ori(r25, r25, Operand(0x20));  // Also convert input character.
+    __ cmp(r25, r6);
+    __ bne(&fail);
+    __ subi(r6, r6, Operand('a'));
+    __ cmpli(r6, Operand('z' - 'a'));  // Is r6 a lowercase letter?
+    __ ble(&loop_check);  // In range 'a'-'z'.
+    // Latin-1: Check for values in range [224,254] but not 247.
+    __ subi(r6, r6, Operand(224 - 'a'));
+    __ cmpli(r6, Operand(254 - 224));
+    __ bgt(&fail);  // Weren't Latin-1 letters.
+    __ cmpi(r6, Operand(247 - 224));  // Check for 247.
+    __ beq(&fail);
+
+    __ bind(&loop_check);
+    __ cmp(r3, r4);
+    __ blt(&loop);
+    __ b(&success);
+
+    __ bind(&fail);
+    BranchOrBacktrack(al, on_no_match);
+
+    __ bind(&success);
+    // Compute new value of character position after the matched part.
+    __ sub(current_input_offset(), r5, end_of_input_address());
+  } else {
+    DCHECK(mode_ == UC16);
+    int argument_count = 4;
+    __ PrepareCallCFunction(argument_count, r5);
+
+    // r3 - offset of start of capture
+    // r4 - length of capture
+
+    // Put arguments into arguments registers.
+    // Parameters are
+    //   r3: Address byte_offset1 - Address captured substring's start.
+    //   r4: Address byte_offset2 - Address of current character position.
+    //   r5: size_t byte_length - length of capture in bytes(!)
+    //   r6: Isolate* isolate
+
+    // Address of start of capture.
+    __ add(r3, r3, end_of_input_address());
+    // Length of capture.
+    __ mr(r5, r4);
+    // Save length in callee-save register for use on return.
+    __ mr(r25, r4);
+    // Address of current input position.
+    __ add(r4, current_input_offset(), end_of_input_address());
+    // Isolate.
+    __ mov(r6, Operand(ExternalReference::isolate_address(isolate())));
+
+    {
+      AllowExternalCallThatCantCauseGC scope(masm_);
+      ExternalReference function =
+          ExternalReference::re_case_insensitive_compare_uc16(isolate());
+      __ CallCFunction(function, argument_count);
+    }
+
+    // Check if function returned non-zero for success or zero for failure.
+    __ cmpi(r3, Operand::Zero());
+    BranchOrBacktrack(eq, on_no_match);
+    // On success, increment position by length of capture.
+    __ add(current_input_offset(), current_input_offset(), r25);
+  }
+
+  __ bind(&fallthrough);
+}
+
+
+void RegExpMacroAssemblerPPC::CheckNotBackReference(
+    int start_reg,
+    Label* on_no_match) {
+  Label fallthrough;
+  Label success;
+
+  // Find length of back-referenced capture.
+  __ LoadP(r3, register_location(start_reg), r0);
+  __ LoadP(r4, register_location(start_reg + 1), r0);
+  __ sub(r4, r4, r3, LeaveOE, SetRC);  // Length to check.
+  // Succeed on empty capture (including no capture).
+  __ beq(&fallthrough, cr0);
+
+  // Check that there are enough characters left in the input.
+  __ add(r0, r4, current_input_offset(), LeaveOE, SetRC);
+  BranchOrBacktrack(gt, on_no_match, cr0);
+
+  // Compute pointers to match string and capture string
+  __ add(r3, r3, end_of_input_address());
+  __ add(r5, end_of_input_address(), current_input_offset());
+  __ add(r4, r4, r3);
+
+  Label loop;
+  __ bind(&loop);
+  if (mode_ == ASCII) {
+    __ lbz(r6, MemOperand(r3));
+    __ addi(r3, r3, Operand(char_size()));
+    __ lbz(r25, MemOperand(r5));
+    __ addi(r5, r5, Operand(char_size()));
+  } else {
+    DCHECK(mode_ == UC16);
+    __ lhz(r6, MemOperand(r3));
+    __ addi(r3, r3, Operand(char_size()));
+    __ lhz(r25, MemOperand(r5));
+    __ addi(r5, r5, Operand(char_size()));
+  }
+  __ cmp(r6, r25);
+  BranchOrBacktrack(ne, on_no_match);
+  __ cmp(r3, r4);
+  __ blt(&loop);
+
+  // Move current character position to position after match.
+  __ sub(current_input_offset(), r5, end_of_input_address());
+  __ bind(&fallthrough);
+}
+
+
+void RegExpMacroAssemblerPPC::CheckNotCharacter(unsigned c,
+                                                Label* on_not_equal) {
+  __ Cmpli(current_character(), Operand(c), r0);
+  BranchOrBacktrack(ne, on_not_equal);
+}
+
+
+void RegExpMacroAssemblerPPC::CheckCharacterAfterAnd(uint32_t c,
+                                                     uint32_t mask,
+                                                     Label* on_equal) {
+  __ mov(r0, Operand(mask));
+  if (c == 0) {
+    __ and_(r3, current_character(), r0, SetRC);
+  } else {
+    __ and_(r3, current_character(), r0);
+    __ Cmpli(r3, Operand(c), r0, cr0);
+  }
+  BranchOrBacktrack(eq, on_equal, cr0);
+}
+
+
+void RegExpMacroAssemblerPPC::CheckNotCharacterAfterAnd(unsigned c,
+                                                        unsigned mask,
+                                                        Label* on_not_equal) {
+  __ mov(r0, Operand(mask));
+  if (c == 0) {
+    __ and_(r3, current_character(), r0, SetRC);
+  } else {
+    __ and_(r3, current_character(), r0);
+    __ Cmpli(r3, Operand(c), r0, cr0);
+  }
+  BranchOrBacktrack(ne, on_not_equal, cr0);
+}
+
+
+void RegExpMacroAssemblerPPC::CheckNotCharacterAfterMinusAnd(
+    uc16 c,
+    uc16 minus,
+    uc16 mask,
+    Label* on_not_equal) {
+  DCHECK(minus < String::kMaxUtf16CodeUnit);
+  __ subi(r3, current_character(), Operand(minus));
+  __ mov(r0, Operand(mask));
+  __ and_(r3, r3, r0);
+  __ Cmpli(r3, Operand(c), r0);
+  BranchOrBacktrack(ne, on_not_equal);
+}
+
+
+void RegExpMacroAssemblerPPC::CheckCharacterInRange(
+    uc16 from,
+    uc16 to,
+    Label* on_in_range) {
+  __ mov(r0, Operand(from));
+  __ sub(r3, current_character(), r0);
+  __ Cmpli(r3, Operand(to - from), r0);
+  BranchOrBacktrack(le, on_in_range);  // Unsigned lower-or-same condition.
+}
+
+
+void RegExpMacroAssemblerPPC::CheckCharacterNotInRange(
+    uc16 from,
+    uc16 to,
+    Label* on_not_in_range) {
+  __ mov(r0, Operand(from));
+  __ sub(r3, current_character(), r0);
+  __ Cmpli(r3, Operand(to - from), r0);
+  BranchOrBacktrack(gt, on_not_in_range);  // Unsigned higher condition.
+}
+
+
+void RegExpMacroAssemblerPPC::CheckBitInTable(
+    Handle<ByteArray> table,
+    Label* on_bit_set) {
+  __ mov(r3, Operand(table));
+  if (mode_ != ASCII || kTableMask != String::kMaxOneByteCharCode) {
+    __ andi(r4, current_character(), Operand(kTableSize - 1));
+    __ addi(r4, r4, Operand(ByteArray::kHeaderSize - kHeapObjectTag));
+  } else {
+    __ addi(r4,
+            current_character(),
+            Operand(ByteArray::kHeaderSize - kHeapObjectTag));
+  }
+  __ lbzx(r3, MemOperand(r3, r4));
+  __ cmpi(r3, Operand::Zero());
+  BranchOrBacktrack(ne, on_bit_set);
+}
+
+
+bool RegExpMacroAssemblerPPC::CheckSpecialCharacterClass(uc16 type,
+                                                         Label* on_no_match) {
+  // Range checks (c in min..max) are generally implemented by an unsigned
+  // (c - min) <= (max - min) check
+  switch (type) {
+  case 's':
+    // Match space-characters
+    if (mode_ == ASCII) {
+      // One byte space characters are '\t'..'\r', ' ' and \u00a0.
+      Label success;
+      __ cmpi(current_character(), Operand(' '));
+      __ beq(&success);
+      // Check range 0x09..0x0d
+      __ subi(r3, current_character(), Operand('\t'));
+      __ cmpli(r3, Operand('\r' - '\t'));
+      __ ble(&success);
+      // \u00a0 (NBSP).
+      __ cmpi(r3, Operand(0x00a0 - '\t'));
+      BranchOrBacktrack(ne, on_no_match);
+      __ bind(&success);
+      return true;
+    }
+    return false;
+  case 'S':
+    // The emitted code for generic character classes is good enough.
+    return false;
+  case 'd':
+    // Match ASCII digits ('0'..'9')
+    __ subi(r3, current_character(), Operand('0'));
+    __ cmpli(r3, Operand('9' - '0'));
+    BranchOrBacktrack(gt, on_no_match);
+    return true;
+  case 'D':
+    // Match non ASCII-digits
+    __ subi(r3, current_character(), Operand('0'));
+    __ cmpli(r3, Operand('9' - '0'));
+    BranchOrBacktrack(le, on_no_match);
+    return true;
+  case '.': {
+    // Match non-newlines (not 0x0a('\n'), 0x0d('\r'), 0x2028 and 0x2029)
+    __ xori(r3, current_character(), Operand(0x01));
+    // See if current character is '\n'^1 or '\r'^1, i.e., 0x0b or 0x0c
+    __ subi(r3, r3, Operand(0x0b));
+    __ cmpli(r3, Operand(0x0c - 0x0b));
+    BranchOrBacktrack(le, on_no_match);
+    if (mode_ == UC16) {
+      // Compare original value to 0x2028 and 0x2029, using the already
+      // computed (current_char ^ 0x01 - 0x0b). I.e., check for
+      // 0x201d (0x2028 - 0x0b) or 0x201e.
+      __ subi(r3, r3, Operand(0x2028 - 0x0b));
+      __ cmpli(r3, Operand(1));
+      BranchOrBacktrack(le, on_no_match);
+    }
+    return true;
+  }
+  case 'n': {
+    // Match newlines (0x0a('\n'), 0x0d('\r'), 0x2028 and 0x2029)
+    __ xori(r3, current_character(), Operand(0x01));
+    // See if current character is '\n'^1 or '\r'^1, i.e., 0x0b or 0x0c
+    __ subi(r3, r3, Operand(0x0b));
+    __ cmpli(r3, Operand(0x0c - 0x0b));
+    if (mode_ == ASCII) {
+      BranchOrBacktrack(gt, on_no_match);
+    } else {
+      Label done;
+      __ ble(&done);
+      // Compare original value to 0x2028 and 0x2029, using the already
+      // computed (current_char ^ 0x01 - 0x0b). I.e., check for
+      // 0x201d (0x2028 - 0x0b) or 0x201e.
+      __ subi(r3, r3, Operand(0x2028 - 0x0b));
+      __ cmpli(r3, Operand(1));
+      BranchOrBacktrack(gt, on_no_match);
+      __ bind(&done);
+    }
+    return true;
+  }
+  case 'w': {
+    if (mode_ != ASCII) {
+      // Table is 128 entries, so all ASCII characters can be tested.
+      __ cmpi(current_character(), Operand('z'));
+      BranchOrBacktrack(gt, on_no_match);
+    }
+    ExternalReference map = ExternalReference::re_word_character_map();
+    __ mov(r3, Operand(map));
+    __ lbzx(r3, MemOperand(r3, current_character()));
+    __ cmpli(r3, Operand::Zero());
+    BranchOrBacktrack(eq, on_no_match);
+    return true;
+  }
+  case 'W': {
+    Label done;
+    if (mode_ != ASCII) {
+      // Table is 128 entries, so all ASCII characters can be tested.
+      __ cmpli(current_character(), Operand('z'));
+      __ bgt(&done);
+    }
+    ExternalReference map = ExternalReference::re_word_character_map();
+    __ mov(r3, Operand(map));
+    __ lbzx(r3, MemOperand(r3, current_character()));
+    __ cmpli(r3, Operand::Zero());
+    BranchOrBacktrack(ne, on_no_match);
+    if (mode_ != ASCII) {
+      __ bind(&done);
+    }
+    return true;
+  }
+  case '*':
+    // Match any character.
+    return true;
+  // No custom implementation (yet): s(UC16), S(UC16).
+  default:
+    return false;
+  }
+}
+
+
+void RegExpMacroAssemblerPPC::Fail() {
+  __ li(r3, Operand(FAILURE));
+  __ b(&exit_label_);
+}
+
+
+Handle<HeapObject> RegExpMacroAssemblerPPC::GetCode(Handle<String> source) {
+  Label return_r3;
+
+  if (masm_->has_exception()) {
+    // If the code gets corrupted due to long regular expressions and lack of
+    // space on trampolines, an internal exception flag is set. If this case
+    // is detected, we will jump into exit sequence right away.
+    __ bind_to(&entry_label_, internal_failure_label_.pos());
+  } else {
+    // Finalize code - write the entry point code now we know how many
+    // registers we need.
+
+    // Entry code:
+    __ bind(&entry_label_);
+
+    // Tell the system that we have a stack frame.  Because the type
+    // is MANUAL, no is generated.
+    FrameScope scope(masm_, StackFrame::MANUAL);
+
+    // Ensure register assigments are consistent with callee save mask
+    DCHECK(r25.bit() & kRegExpCalleeSaved);
+    DCHECK(code_pointer().bit() & kRegExpCalleeSaved);
+    DCHECK(current_input_offset().bit() & kRegExpCalleeSaved);
+    DCHECK(current_character().bit() & kRegExpCalleeSaved);
+    DCHECK(backtrack_stackpointer().bit() & kRegExpCalleeSaved);
+    DCHECK(end_of_input_address().bit() & kRegExpCalleeSaved);
+    DCHECK(frame_pointer().bit() & kRegExpCalleeSaved);
+
+    // Actually emit code to start a new stack frame.
+    // Push arguments
+    // Save callee-save registers.
+    // Start new stack frame.
+    // Store link register in existing stack-cell.
+    // Order here should correspond to order of offset constants in header file.
+    RegList registers_to_retain = kRegExpCalleeSaved;
+    RegList argument_registers = r3.bit() | r4.bit() | r5.bit() | r6.bit() |
+      r7.bit() | r8.bit() | r9.bit() | r10.bit();
+    __ mflr(r0);
+    __ push(r0);
+    __ MultiPush(argument_registers | registers_to_retain);
+    // Set frame pointer in space for it if this is not a direct call
+    // from generated code.
+    __ addi(frame_pointer(), sp, Operand(8 * kPointerSize));
+    __ li(r3, Operand::Zero());
+    __ push(r3);  // Make room for success counter and initialize it to 0.
+    __ push(r3);  // Make room for "position - 1" constant (value is irrelevant)
+    // Check if we have space on the stack for registers.
+    Label stack_limit_hit;
+    Label stack_ok;
+
+    ExternalReference stack_limit =
+      ExternalReference::address_of_stack_limit(isolate());
+    __ mov(r3, Operand(stack_limit));
+    __ LoadP(r3, MemOperand(r3));
+    __ sub(r3, sp, r3, LeaveOE, SetRC);
+    // Handle it if the stack pointer is already below the stack limit.
+    __ ble(&stack_limit_hit, cr0);
+    // Check if there is room for the variable number of registers above
+    // the stack limit.
+    __ Cmpli(r3, Operand(num_registers_ * kPointerSize), r0);
+    __ bge(&stack_ok);
+    // Exit with OutOfMemory exception. There is not enough space on the stack
+    // for our working registers.
+    __ li(r3, Operand(EXCEPTION));
+    __ b(&return_r3);
+
+    __ bind(&stack_limit_hit);
+    CallCheckStackGuardState(r3);
+    __ cmpi(r3, Operand::Zero());
+    // If returned value is non-zero, we exit with the returned value as result.
+    __ bne(&return_r3);
+
+    __ bind(&stack_ok);
+
+    // Allocate space on stack for registers.
+    __ Add(sp, sp, -num_registers_ * kPointerSize, r0);
+    // Load string end.
+    __ LoadP(end_of_input_address(), MemOperand(frame_pointer(), kInputEnd));
+    // Load input start.
+    __ LoadP(r3, MemOperand(frame_pointer(), kInputStart));
+    // Find negative length (offset of start relative to end).
+    __ sub(current_input_offset(), r3, end_of_input_address());
+    // Set r3 to address of char before start of the input string
+    // (effectively string position -1).
+    __ LoadP(r4, MemOperand(frame_pointer(), kStartIndex));
+    __ subi(r3, current_input_offset(), Operand(char_size()));
+    if (mode_ == UC16) {
+      __ ShiftLeftImm(r0, r4, Operand(1));
+      __ sub(r3, r3, r0);
+    } else {
+      __ sub(r3, r3, r4);
+    }
+    // Store this value in a local variable, for use when clearing
+    // position registers.
+    __ StoreP(r3, MemOperand(frame_pointer(), kInputStartMinusOne));
+
+    // Initialize code pointer register
+    __ mov(code_pointer(), Operand(masm_->CodeObject()));
+
+    Label load_char_start_regexp, start_regexp;
+    // Load newline if index is at start, previous character otherwise.
+    __ cmpi(r4, Operand::Zero());
+    __ bne(&load_char_start_regexp);
+    __ li(current_character(), Operand('\n'));
+    __ b(&start_regexp);
+
+    // Global regexp restarts matching here.
+    __ bind(&load_char_start_regexp);
+    // Load previous char as initial value of current character register.
+    LoadCurrentCharacterUnchecked(-1, 1);
+    __ bind(&start_regexp);
+
+    // Initialize on-stack registers.
+    if (num_saved_registers_ > 0) {  // Always is, if generated from a regexp.
+      // Fill saved registers with initial value = start offset - 1
+      if (num_saved_registers_ > 8) {
+        // One slot beyond address of register 0.
+        __ addi(r4, frame_pointer(), Operand(kRegisterZero + kPointerSize));
+        __ li(r5, Operand(num_saved_registers_));
+        __ mtctr(r5);
+        Label init_loop;
+        __ bind(&init_loop);
+        __ StorePU(r3, MemOperand(r4, -kPointerSize));
+        __ bdnz(&init_loop);
+      } else {
+        for (int i = 0; i < num_saved_registers_; i++) {
+          __ StoreP(r3, register_location(i), r0);
+        }
+      }
+    }
+
+    // Initialize backtrack stack pointer.
+    __ LoadP(backtrack_stackpointer(),
+             MemOperand(frame_pointer(), kStackHighEnd));
+
+    __ b(&start_label_);
+
+    // Exit code:
+    if (success_label_.is_linked()) {
+      // Save captures when successful.
+      __ bind(&success_label_);
+      if (num_saved_registers_ > 0) {
+        // copy captures to output
+        __ LoadP(r4, MemOperand(frame_pointer(), kInputStart));
+        __ LoadP(r3, MemOperand(frame_pointer(), kRegisterOutput));
+        __ LoadP(r5, MemOperand(frame_pointer(), kStartIndex));
+        __ sub(r4, end_of_input_address(), r4);
+        // r4 is length of input in bytes.
+        if (mode_ == UC16) {
+          __ ShiftRightImm(r4, r4, Operand(1));
+        }
+        // r4 is length of input in characters.
+        __ add(r4, r4, r5);
+        // r4 is length of string in characters.
+
+        DCHECK_EQ(0, num_saved_registers_ % 2);
+        // Always an even number of capture registers. This allows us to
+        // unroll the loop once to add an operation between a load of a register
+        // and the following use of that register.
+        for (int i = 0; i < num_saved_registers_; i += 2) {
+          __ LoadP(r5, register_location(i), r0);
+          __ LoadP(r6, register_location(i + 1), r0);
+          if (i == 0 && global_with_zero_length_check()) {
+            // Keep capture start in r25 for the zero-length check later.
+            __ mr(r25, r5);
+          }
+          if (mode_ == UC16) {
+            __ ShiftRightArithImm(r5, r5, 1);
+            __ add(r5, r4, r5);
+            __ ShiftRightArithImm(r6, r6, 1);
+            __ add(r6, r4, r6);
+          } else {
+            __ add(r5, r4, r5);
+            __ add(r6, r4, r6);
+          }
+          __ stw(r5, MemOperand(r3));
+          __ addi(r3, r3, Operand(kIntSize));
+          __ stw(r6, MemOperand(r3));
+          __ addi(r3, r3, Operand(kIntSize));
+        }
+      }
+
+      if (global()) {
+        // Restart matching if the regular expression is flagged as global.
+        __ LoadP(r3, MemOperand(frame_pointer(), kSuccessfulCaptures));
+        __ LoadP(r4, MemOperand(frame_pointer(), kNumOutputRegisters));
+        __ LoadP(r5, MemOperand(frame_pointer(), kRegisterOutput));
+        // Increment success counter.
+        __ addi(r3, r3, Operand(1));
+        __ StoreP(r3, MemOperand(frame_pointer(), kSuccessfulCaptures));
+        // Capture results have been stored, so the number of remaining global
+        // output registers is reduced by the number of stored captures.
+        __ subi(r4, r4, Operand(num_saved_registers_));
+        // Check whether we have enough room for another set of capture results.
+        __ cmpi(r4, Operand(num_saved_registers_));
+        __ blt(&return_r3);
+
+        __ StoreP(r4, MemOperand(frame_pointer(), kNumOutputRegisters));
+        // Advance the location for output.
+        __ addi(r5, r5, Operand(num_saved_registers_ * kIntSize));
+        __ StoreP(r5, MemOperand(frame_pointer(), kRegisterOutput));
+
+        // Prepare r3 to initialize registers with its value in the next run.
+        __ LoadP(r3, MemOperand(frame_pointer(), kInputStartMinusOne));
+
+        if (global_with_zero_length_check()) {
+          // Special case for zero-length matches.
+          // r25: capture start index
+          __ cmp(current_input_offset(), r25);
+          // Not a zero-length match, restart.
+          __ bne(&load_char_start_regexp);
+          // Offset from the end is zero if we already reached the end.
+          __ cmpi(current_input_offset(), Operand::Zero());
+          __ beq(&exit_label_);
+          // Advance current position after a zero-length match.
+          __ addi(current_input_offset(),
+                  current_input_offset(),
+                  Operand((mode_ == UC16) ? 2 : 1));
+        }
+
+        __ b(&load_char_start_regexp);
+      } else {
+        __ li(r3, Operand(SUCCESS));
+      }
+    }
+
+    // Exit and return r3
+    __ bind(&exit_label_);
+    if (global()) {
+      __ LoadP(r3, MemOperand(frame_pointer(), kSuccessfulCaptures));
+    }
+
+    __ bind(&return_r3);
+    // Skip sp past regexp registers and local variables..
+    __ mr(sp, frame_pointer());
+    // Restore registers r25..r31 and return (restoring lr to pc).
+    __ MultiPop(registers_to_retain);
+    __ pop(r0);
+    __ mtctr(r0);
+    __ bctr();
+
+    // Backtrack code (branch target for conditional backtracks).
+    if (backtrack_label_.is_linked()) {
+      __ bind(&backtrack_label_);
+      Backtrack();
+    }
+
+    Label exit_with_exception;
+
+    // Preempt-code
+    if (check_preempt_label_.is_linked()) {
+      SafeCallTarget(&check_preempt_label_);
+
+      CallCheckStackGuardState(r3);
+      __ cmpi(r3, Operand::Zero());
+      // If returning non-zero, we should end execution with the given
+      // result as return value.
+      __ bne(&return_r3);
+
+      // String might have moved: Reload end of string from frame.
+      __ LoadP(end_of_input_address(), MemOperand(frame_pointer(), kInputEnd));
+      SafeReturn();
+    }
+
+    // Backtrack stack overflow code.
+    if (stack_overflow_label_.is_linked()) {
+      SafeCallTarget(&stack_overflow_label_);
+      // Reached if the backtrack-stack limit has been hit.
+      Label grow_failed;
+
+      // Call GrowStack(backtrack_stackpointer(), &stack_base)
+      static const int num_arguments = 3;
+      __ PrepareCallCFunction(num_arguments, r3);
+      __ mr(r3, backtrack_stackpointer());
+      __ addi(r4, frame_pointer(), Operand(kStackHighEnd));
+      __ mov(r5, Operand(ExternalReference::isolate_address(isolate())));
+      ExternalReference grow_stack =
+        ExternalReference::re_grow_stack(isolate());
+      __ CallCFunction(grow_stack, num_arguments);
+      // If return NULL, we have failed to grow the stack, and
+      // must exit with a stack-overflow exception.
+      __ cmpi(r3, Operand::Zero());
+      __ beq(&exit_with_exception);
+      // Otherwise use return value as new stack pointer.
+      __ mr(backtrack_stackpointer(), r3);
+      // Restore saved registers and continue.
+      SafeReturn();
+    }
+
+    if (exit_with_exception.is_linked()) {
+      // If any of the code above needed to exit with an exception.
+      __ bind(&exit_with_exception);
+      // Exit with Result EXCEPTION(-1) to signal thrown exception.
+      __ li(r3, Operand(EXCEPTION));
+      __ b(&return_r3);
+    }
+  }
+
+  CodeDesc code_desc;
+  masm_->GetCode(&code_desc);
+  Handle<Code> code = isolate()->factory()->NewCode(
+      code_desc, Code::ComputeFlags(Code::REGEXP), masm_->CodeObject());
+  PROFILE(masm_->isolate(), RegExpCodeCreateEvent(*code, *source));
+  return Handle<HeapObject>::cast(code);
+}
+
+
+void RegExpMacroAssemblerPPC::GoTo(Label* to) {
+  BranchOrBacktrack(al, to);
+}
+
+
+void RegExpMacroAssemblerPPC::IfRegisterGE(int reg,
+                                           int comparand,
+                                           Label* if_ge) {
+  __ LoadP(r3, register_location(reg), r0);
+  __ Cmpi(r3, Operand(comparand), r0);
+  BranchOrBacktrack(ge, if_ge);
+}
+
+
+void RegExpMacroAssemblerPPC::IfRegisterLT(int reg,
+                                           int comparand,
+                                           Label* if_lt) {
+  __ LoadP(r3, register_location(reg), r0);
+  __ Cmpi(r3, Operand(comparand), r0);
+  BranchOrBacktrack(lt, if_lt);
+}
+
+
+void RegExpMacroAssemblerPPC::IfRegisterEqPos(int reg,
+                                              Label* if_eq) {
+  __ LoadP(r3, register_location(reg), r0);
+  __ cmp(r3, current_input_offset());
+  BranchOrBacktrack(eq, if_eq);
+}
+
+
+RegExpMacroAssembler::IrregexpImplementation
+    RegExpMacroAssemblerPPC::Implementation() {
+  return kPPCImplementation;
+}
+
+
+void RegExpMacroAssemblerPPC::LoadCurrentCharacter(int cp_offset,
+                                                   Label* on_end_of_input,
+                                                   bool check_bounds,
+                                                   int characters) {
+  DCHECK(cp_offset >= -1);      // ^ and \b can look behind one character.
+  DCHECK(cp_offset < (1<<30));  // Be sane! (And ensure negation works)
+  if (check_bounds) {
+    CheckPosition(cp_offset + characters - 1, on_end_of_input);
+  }
+  LoadCurrentCharacterUnchecked(cp_offset, characters);
+}
+
+
+void RegExpMacroAssemblerPPC::PopCurrentPosition() {
+  Pop(current_input_offset());
+}
+
+
+void RegExpMacroAssemblerPPC::PopRegister(int register_index) {
+  Pop(r3);
+  __ StoreP(r3, register_location(register_index), r0);
+}
+
+
+void RegExpMacroAssemblerPPC::PushBacktrack(Label* label) {
+  __ mov_label_offset(r3, label);
+  Push(r3);
+  CheckStackLimit();
+}
+
+
+void RegExpMacroAssemblerPPC::PushCurrentPosition() {
+  Push(current_input_offset());
+}
+
+
+void RegExpMacroAssemblerPPC::PushRegister(int register_index,
+                                           StackCheckFlag check_stack_limit) {
+  __ LoadP(r3, register_location(register_index), r0);
+  Push(r3);
+  if (check_stack_limit) CheckStackLimit();
+}
+
+
+void RegExpMacroAssemblerPPC::ReadCurrentPositionFromRegister(int reg) {
+  __ LoadP(current_input_offset(), register_location(reg), r0);
+}
+
+
+void RegExpMacroAssemblerPPC::ReadStackPointerFromRegister(int reg) {
+  __ LoadP(backtrack_stackpointer(), register_location(reg), r0);
+  __ LoadP(r3, MemOperand(frame_pointer(), kStackHighEnd));
+  __ add(backtrack_stackpointer(), backtrack_stackpointer(), r3);
+}
+
+
+void RegExpMacroAssemblerPPC::SetCurrentPositionFromEnd(int by) {
+  Label after_position;
+  __ Cmpi(current_input_offset(), Operand(-by * char_size()), r0);
+  __ bge(&after_position);
+  __ mov(current_input_offset(), Operand(-by * char_size()));
+  // On RegExp code entry (where this operation is used), the character before
+  // the current position is expected to be already loaded.
+  // We have advanced the position, so it's safe to read backwards.
+  LoadCurrentCharacterUnchecked(-1, 1);
+  __ bind(&after_position);
+}
+
+
+void RegExpMacroAssemblerPPC::SetRegister(int register_index, int to) {
+  DCHECK(register_index >= num_saved_registers_);  // Reserved for positions!
+  __ mov(r3, Operand(to));
+  __ StoreP(r3, register_location(register_index), r0);
+}
+
+
+bool RegExpMacroAssemblerPPC::Succeed() {
+  __ b(&success_label_);
+  return global();
+}
+
+
+void RegExpMacroAssemblerPPC::WriteCurrentPositionToRegister(int reg,
+                                                             int cp_offset) {
+  if (cp_offset == 0) {
+    __ StoreP(current_input_offset(), register_location(reg), r0);
+  } else {
+    __ mov(r0, Operand(cp_offset * char_size()));
+    __ add(r3, current_input_offset(), r0);
+    __ StoreP(r3, register_location(reg), r0);
+  }
+}
+
+
+void RegExpMacroAssemblerPPC::ClearRegisters(int reg_from, int reg_to) {
+  DCHECK(reg_from <= reg_to);
+  __ LoadP(r3, MemOperand(frame_pointer(), kInputStartMinusOne));
+  for (int reg = reg_from; reg <= reg_to; reg++) {
+    __ StoreP(r3, register_location(reg), r0);
+  }
+}
+
+
+void RegExpMacroAssemblerPPC::WriteStackPointerToRegister(int reg) {
+  __ LoadP(r4, MemOperand(frame_pointer(), kStackHighEnd));
+  __ sub(r3, backtrack_stackpointer(), r4);
+  __ StoreP(r3, register_location(reg), r0);
+}
+
+
+// Private methods:
+
+void RegExpMacroAssemblerPPC::CallCheckStackGuardState(Register scratch) {
+  int frame_alignment = masm_->ActivationFrameAlignment();
+  int stack_space = kNumRequiredStackFrameSlots;
+  int stack_passed_arguments = 1;  // space for return address pointer
+
+  // The following stack manipulation logic is similar to
+  // PrepareCallCFunction.  However, we need an extra slot on the
+  // stack to house the return address parameter.
+  if (frame_alignment > kPointerSize) {
+    // Make stack end at alignment and make room for stack arguments
+    // -- preserving original value of sp.
+    __ mr(scratch, sp);
+    __ addi(sp, sp, Operand(-(stack_passed_arguments + 1) * kPointerSize));
+    DCHECK(IsPowerOf2(frame_alignment));
+    __ ClearRightImm(sp, sp, Operand(WhichPowerOf2(frame_alignment)));
+    __ StoreP(scratch, MemOperand(sp, stack_passed_arguments * kPointerSize));
+  } else {
+    // Make room for stack arguments
+    stack_space += stack_passed_arguments;
+  }
+
+  // Allocate frame with required slots to make ABI work.
+  __ li(r0, Operand::Zero());
+  __ StorePU(r0, MemOperand(sp, -stack_space * kPointerSize));
+
+  // RegExp code frame pointer.
+  __ mr(r5, frame_pointer());
+  // Code* of self.
+  __ mov(r4, Operand(masm_->CodeObject()));
+  // r3 will point to the return address, placed by DirectCEntry.
+  __ addi(r3, sp, Operand(kStackFrameExtraParamSlot * kPointerSize));
+
+  ExternalReference stack_guard_check =
+      ExternalReference::re_check_stack_guard_state(isolate());
+  __ mov(ip, Operand(stack_guard_check));
+  DirectCEntryStub stub(isolate());
+  stub.GenerateCall(masm_, ip);
+
+  // Restore the stack pointer
+  stack_space = kNumRequiredStackFrameSlots + stack_passed_arguments;
+  if (frame_alignment > kPointerSize) {
+    __ LoadP(sp, MemOperand(sp, stack_space * kPointerSize));
+  } else {
+    __ addi(sp, sp, Operand(stack_space * kPointerSize));
+  }
+
+  __ mov(code_pointer(), Operand(masm_->CodeObject()));
+}
+
+
+// Helper function for reading a value out of a stack frame.
+template <typename T>
+static T& frame_entry(Address re_frame, int frame_offset) {
+  return reinterpret_cast<T&>(Memory::int32_at(re_frame + frame_offset));
+}
+
+
+int RegExpMacroAssemblerPPC::CheckStackGuardState(Address* return_address,
+                                                  Code* re_code,
+                                                  Address re_frame) {
+  Isolate* isolate = frame_entry<Isolate*>(re_frame, kIsolate);
+  StackLimitCheck check(isolate);
+  if (check.JsHasOverflowed()) {
+    isolate->StackOverflow();
+    return EXCEPTION;
+  }
+
+  // If not real stack overflow the stack guard was used to interrupt
+  // execution for another purpose.
+
+  // If this is a direct call from JavaScript retry the RegExp forcing the call
+  // through the runtime system. Currently the direct call cannot handle a GC.
+  if (frame_entry<int>(re_frame, kDirectCall) == 1) {
+    return RETRY;
+  }
+
+  // Prepare for possible GC.
+  HandleScope handles(isolate);
+  Handle<Code> code_handle(re_code);
+
+  Handle<String> subject(frame_entry<String*>(re_frame, kInputString));
+
+  // Current string.
+  bool is_ascii = subject->IsOneByteRepresentationUnderneath();
+
+  DCHECK(re_code->instruction_start() <= *return_address);
+  DCHECK(*return_address <=
+      re_code->instruction_start() + re_code->instruction_size());
+
+  Object* result = isolate->stack_guard()->HandleInterrupts();
+
+  if (*code_handle != re_code) {  // Return address no longer valid
+    intptr_t delta = code_handle->address() - re_code->address();
+    // Overwrite the return address on the stack.
+    *return_address += delta;
+  }
+
+  if (result->IsException()) {
+    return EXCEPTION;
+  }
+
+  Handle<String> subject_tmp = subject;
+  int slice_offset = 0;
+
+  // Extract the underlying string and the slice offset.
+  if (StringShape(*subject_tmp).IsCons()) {
+    subject_tmp = Handle<String>(ConsString::cast(*subject_tmp)->first());
+  } else if (StringShape(*subject_tmp).IsSliced()) {
+    SlicedString* slice = SlicedString::cast(*subject_tmp);
+    subject_tmp = Handle<String>(slice->parent());
+    slice_offset = slice->offset();
+  }
+
+  // String might have changed.
+  if (subject_tmp->IsOneByteRepresentation() != is_ascii) {
+    // If we changed between an ASCII and an UC16 string, the specialized
+    // code cannot be used, and we need to restart regexp matching from
+    // scratch (including, potentially, compiling a new version of the code).
+    return RETRY;
+  }
+
+  // Otherwise, the content of the string might have moved. It must still
+  // be a sequential or external string with the same content.
+  // Update the start and end pointers in the stack frame to the current
+  // location (whether it has actually moved or not).
+  DCHECK(StringShape(*subject_tmp).IsSequential() ||
+      StringShape(*subject_tmp).IsExternal());
+
+  // The original start address of the characters to match.
+  const byte* start_address = frame_entry<const byte*>(re_frame, kInputStart);
+
+  // Find the current start address of the same character at the current string
+  // position.
+  int start_index = frame_entry<intptr_t>(re_frame, kStartIndex);
+  const byte* new_address = StringCharacterPosition(*subject_tmp,
+                                                    start_index + slice_offset);
+
+  if (start_address != new_address) {
+    // If there is a difference, update the object pointer and start and end
+    // addresses in the RegExp stack frame to match the new value.
+    const byte* end_address = frame_entry<const byte* >(re_frame, kInputEnd);
+    int byte_length = static_cast<int>(end_address - start_address);
+    frame_entry<const String*>(re_frame, kInputString) = *subject;
+    frame_entry<const byte*>(re_frame, kInputStart) = new_address;
+    frame_entry<const byte*>(re_frame, kInputEnd) = new_address + byte_length;
+  } else if (frame_entry<const String*>(re_frame, kInputString) != *subject) {
+    // Subject string might have been a ConsString that underwent
+    // short-circuiting during GC. That will not change start_address but
+    // will change pointer inside the subject handle.
+    frame_entry<const String*>(re_frame, kInputString) = *subject;
+  }
+
+  return 0;
+}
+
+
+MemOperand RegExpMacroAssemblerPPC::register_location(int register_index) {
+  DCHECK(register_index < (1<<30));
+  if (num_registers_ <= register_index) {
+    num_registers_ = register_index + 1;
+  }
+  return MemOperand(frame_pointer(),
+                    kRegisterZero - register_index * kPointerSize);
+}
+
+
+void RegExpMacroAssemblerPPC::CheckPosition(int cp_offset,
+                                            Label* on_outside_input) {
+  __ Cmpi(current_input_offset(), Operand(-cp_offset * char_size()), r0);
+  BranchOrBacktrack(ge, on_outside_input);
+}
+
+
+void RegExpMacroAssemblerPPC::BranchOrBacktrack(Condition condition,
+                                                Label* to,
+                                                CRegister cr) {
+  if (condition == al) {  // Unconditional.
+    if (to == NULL) {
+      Backtrack();
+      return;
+    }
+    __ b(to);
+    return;
+  }
+  if (to == NULL) {
+    __ b(condition, &backtrack_label_, cr);
+    return;
+  }
+  __ b(condition, to, cr);
+}
+
+
+void RegExpMacroAssemblerPPC::SafeCall(Label* to, Condition cond,
+                                       CRegister cr) {
+  __ b(cond, to, cr, SetLK);
+}
+
+
+void RegExpMacroAssemblerPPC::SafeReturn() {
+  __ pop(r0);
+  __ mov(ip, Operand(masm_->CodeObject()));
+  __ add(r0, r0, ip);
+  __ mtlr(r0);
+  __ blr();
+}
+
+
+void RegExpMacroAssemblerPPC::SafeCallTarget(Label* name) {
+  __ bind(name);
+  __ mflr(r0);
+  __ mov(ip, Operand(masm_->CodeObject()));
+  __ sub(r0, r0, ip);
+  __ push(r0);
+}
+
+
+void RegExpMacroAssemblerPPC::Push(Register source) {
+  DCHECK(!source.is(backtrack_stackpointer()));
+  __ StorePU(source, MemOperand(backtrack_stackpointer(), -kPointerSize));
+}
+
+
+void RegExpMacroAssemblerPPC::Pop(Register target) {
+  DCHECK(!target.is(backtrack_stackpointer()));
+  __ LoadP(target, MemOperand(backtrack_stackpointer()));
+  __ addi(backtrack_stackpointer(), backtrack_stackpointer(),
+          Operand(kPointerSize));
+}
+
+
+void RegExpMacroAssemblerPPC::CheckPreemption() {
+  // Check for preemption.
+  ExternalReference stack_limit =
+      ExternalReference::address_of_stack_limit(isolate());
+  __ mov(r3, Operand(stack_limit));
+  __ LoadP(r3, MemOperand(r3));
+  __ cmpl(sp, r3);
+  SafeCall(&check_preempt_label_, le);
+}
+
+
+void RegExpMacroAssemblerPPC::CheckStackLimit() {
+  ExternalReference stack_limit =
+      ExternalReference::address_of_regexp_stack_limit(isolate());
+  __ mov(r3, Operand(stack_limit));
+  __ LoadP(r3, MemOperand(r3));
+  __ cmpl(backtrack_stackpointer(), r3);
+  SafeCall(&stack_overflow_label_, le);
+}
+
+
+bool RegExpMacroAssemblerPPC::CanReadUnaligned() {
+  return CpuFeatures::IsSupported(UNALIGNED_ACCESSES) && !slow_safe();
+}
+
+
+void RegExpMacroAssemblerPPC::LoadCurrentCharacterUnchecked(int cp_offset,
+                                                            int characters) {
+  Register offset = current_input_offset();
+  if (cp_offset != 0) {
+    // r25 is not being used to store the capture start index at this point.
+    __ addi(r25, current_input_offset(), Operand(cp_offset * char_size()));
+    offset = r25;
+  }
+  // The lwz, stw, lhz, sth instructions can do unaligned accesses, if the CPU
+  // and the operating system running on the target allow it.
+  // We assume we don't want to do unaligned loads on PPC, so this function
+  // must only be used to load a single character at a time.
+
+  DCHECK(characters == 1);
+  __ add(current_character(), end_of_input_address(), offset);
+  if (mode_ == ASCII) {
+    __ lbz(current_character(), MemOperand(current_character()));
+  } else {
+    DCHECK(mode_ == UC16);
+    __ lhz(current_character(), MemOperand(current_character()));
+  }
+}
+
+
+#undef __
+
+#endif  // V8_INTERPRETED_REGEXP
+
+}}  // namespace v8::internal
+
+#endif  // V8_TARGET_ARCH_PPC