text: // Copyright 2011 the V8 project authors. All rights reserved.
  // Use of this source code is governed by a BSD-style license that can be
  // found in the LICENSE file.
  
  #ifndef V8_MIPS_CODE_STUBS_ARM_H_
  #define V8_MIPS_CODE_STUBS_ARM_H_
  
  #include "src/ic-inl.h"
  
  
  namespace v8 {
  namespace internal {
  
  
  void ArrayNativeCode(MacroAssembler* masm, Label* call_generic_code);
  
  
  class StoreBufferOverflowStub: public PlatformCodeStub {
   public:
    StoreBufferOverflowStub(Isolate* isolate, SaveFPRegsMode save_fp)
        : PlatformCodeStub(isolate), save_doubles_(save_fp) {}
  
    void Generate(MacroAssembler* masm);
  
    static void GenerateFixedRegStubsAheadOfTime(Isolate* isolate);
    virtual bool SometimesSetsUpAFrame() { return false; }
  
   private:
    SaveFPRegsMode save_doubles_;
  
    Major MajorKey() const { return StoreBufferOverflow; }
    int MinorKey() const { return (save_doubles_ == kSaveFPRegs) ? 1 : 0; }
  };
  
  
  class StringHelper : public AllStatic {
   public:
    // Generate code for copying a large number of characters. This function
    // is allowed to spend extra time setting up conditions to make copying
    // faster. Copying of overlapping regions is not supported.
    // Dest register ends at the position after the last character written.
    static void GenerateCopyCharacters(MacroAssembler* masm,
                                       Register dest,
                                       Register src,
                                       Register count,
                                       Register scratch,
                                       String::Encoding encoding);
  
    // Generate string hash.
    static void GenerateHashInit(MacroAssembler* masm,
                                 Register hash,
                                 Register character);
  
    static void GenerateHashAddCharacter(MacroAssembler* masm,
                                         Register hash,
                                         Register character);
  
    static void GenerateHashGetHash(MacroAssembler* masm,
                                    Register hash);
  
   private:
    DISALLOW_IMPLICIT_CONSTRUCTORS(StringHelper);
  };
  
  
  class SubStringStub: public PlatformCodeStub {
   public:
    explicit SubStringStub(Isolate* isolate) : PlatformCodeStub(isolate) {}
  
   private:
    Major MajorKey() const { return SubString; }
    int MinorKey() const { return 0; }
  
    void Generate(MacroAssembler* masm);
  };
  
  
  class StoreRegistersStateStub: public PlatformCodeStub {
   public:
    explicit StoreRegistersStateStub(Isolate* isolate, SaveFPRegsMode with_fp)
        : PlatformCodeStub(isolate), save_doubles_(with_fp) {}
  
    static void GenerateAheadOfTime(Isolate* isolate);
   private:
    Major MajorKey() const { return StoreRegistersState; }
    int MinorKey() const { return (save_doubles_ == kSaveFPRegs) ? 1 : 0; }
    SaveFPRegsMode save_doubles_;
  
    void Generate(MacroAssembler* masm);
  };
  
  class RestoreRegistersStateStub: public PlatformCodeStub {
   public:
    explicit RestoreRegistersStateStub(Isolate* isolate, SaveFPRegsMode with_fp)
        : PlatformCodeStub(isolate), save_doubles_(with_fp) {}
  
    static void GenerateAheadOfTime(Isolate* isolate);
   private:
    Major MajorKey() const { return RestoreRegistersState; }
    int MinorKey() const { return (save_doubles_ == kSaveFPRegs) ? 1 : 0; }
    SaveFPRegsMode save_doubles_;
  
    void Generate(MacroAssembler* masm);
  };
  
  class StringCompareStub: public PlatformCodeStub {
   public:
    explicit StringCompareStub(Isolate* isolate) : PlatformCodeStub(isolate) { }
  
    // Compare two flat ASCII strings and returns result in v0.
    static void GenerateCompareFlatAsciiStrings(MacroAssembler* masm,
                                                Register left,
                                                Register right,
                                                Register scratch1,
                                                Register scratch2,
                                                Register scratch3,
                                                Register scratch4);
  
    // Compares two flat ASCII strings for equality and returns result
    // in v0.
    static void GenerateFlatAsciiStringEquals(MacroAssembler* masm,
                                              Register left,
                                              Register right,
                                              Register scratch1,
                                              Register scratch2,
                                              Register scratch3);
  
   private:
    virtual Major MajorKey() const { return StringCompare; }
    virtual int MinorKey() const { return 0; }
    virtual void Generate(MacroAssembler* masm);
  
    static void GenerateAsciiCharsCompareLoop(MacroAssembler* masm,
                                              Register left,
                                              Register right,
                                              Register length,
                                              Register scratch1,
                                              Register scratch2,
                                              Register scratch3,
                                              Label* chars_not_equal);
  };
  
  
  // This stub can convert a signed int32 to a heap number (double).  It does
  // not work for int32s that are in Smi range!  No GC occurs during this stub
  // so you don't have to set up the frame.
  class WriteInt32ToHeapNumberStub : public PlatformCodeStub {
   public:
    WriteInt32ToHeapNumberStub(Isolate* isolate,
                               Register the_int,
                               Register the_heap_number,
                               Register scratch,
                               Register scratch2)
        : PlatformCodeStub(isolate),
          the_int_(the_int),
          the_heap_number_(the_heap_number),
          scratch_(scratch),
          sign_(scratch2) {
      ASSERT(IntRegisterBits::is_valid(the_int_.code()));
      ASSERT(HeapNumberRegisterBits::is_valid(the_heap_number_.code()));
      ASSERT(ScratchRegisterBits::is_valid(scratch_.code()));
      ASSERT(SignRegisterBits::is_valid(sign_.code()));
    }
  
    static void GenerateFixedRegStubsAheadOfTime(Isolate* isolate);
  
   private:
    Register the_int_;
    Register the_heap_number_;
    Register scratch_;
    Register sign_;
  
    // Minor key encoding in 16 bits.
    class IntRegisterBits: public BitField<int, 0, 4> {};
    class HeapNumberRegisterBits: public BitField<int, 4, 4> {};
    class ScratchRegisterBits: public BitField<int, 8, 4> {};
    class SignRegisterBits: public BitField<int, 12, 4> {};
  
    Major MajorKey() const { return WriteInt32ToHeapNumber; }
    int MinorKey() const {
      // Encode the parameters in a unique 16 bit value.
      return IntRegisterBits::encode(the_int_.code())
             | HeapNumberRegisterBits::encode(the_heap_number_.code())
             | ScratchRegisterBits::encode(scratch_.code())
             | SignRegisterBits::encode(sign_.code());
    }
  
    void Generate(MacroAssembler* masm);
  };
  
  
  class RecordWriteStub: public PlatformCodeStub {
   public:
    RecordWriteStub(Isolate* isolate,
                    Register object,
                    Register value,
                    Register address,
                    RememberedSetAction remembered_set_action,
                    SaveFPRegsMode fp_mode)
        : PlatformCodeStub(isolate),
          object_(object),
          value_(value),
          address_(address),
          remembered_set_action_(remembered_set_action),
          save_fp_regs_mode_(fp_mode),
          regs_(object,   // An input reg.
                address,  // An input reg.
                value) {  // One scratch reg.
    }
  
    enum Mode {
      STORE_BUFFER_ONLY,
      INCREMENTAL,
      INCREMENTAL_COMPACTION
    };
  
    virtual bool SometimesSetsUpAFrame() { return false; }
  
    static void PatchBranchIntoNop(MacroAssembler* masm, int pos) {
      const unsigned offset = masm->instr_at(pos) & kImm16Mask;
      masm->instr_at_put(pos, BNE | (zero_reg.code() << kRsShift) |
          (zero_reg.code() << kRtShift) | (offset & kImm16Mask));
      ASSERT(Assembler::IsBne(masm->instr_at(pos)));
    }
  
    static void PatchNopIntoBranch(MacroAssembler* masm, int pos) {
      const unsigned offset = masm->instr_at(pos) & kImm16Mask;
      masm->instr_at_put(pos, BEQ | (zero_reg.code() << kRsShift) |
          (zero_reg.code() << kRtShift) | (offset & kImm16Mask));
      ASSERT(Assembler::IsBeq(masm->instr_at(pos)));
    }
  
    static Mode GetMode(Code* stub) {
      Instr first_instruction = Assembler::instr_at(stub->instruction_start());
      Instr second_instruction = Assembler::instr_at(stub->instruction_start() +
                                                     2 * Assembler::kInstrSize);
  
      if (Assembler::IsBeq(first_instruction)) {
        return INCREMENTAL;
      }
  
      ASSERT(Assembler::IsBne(first_instruction));
  
      if (Assembler::IsBeq(second_instruction)) {
        return INCREMENTAL_COMPACTION;
      }
  
      ASSERT(Assembler::IsBne(second_instruction));
  
      return STORE_BUFFER_ONLY;
    }
  
    static void Patch(Code* stub, Mode mode) {
      MacroAssembler masm(NULL,
                          stub->instruction_start(),
                          stub->instruction_size());
      switch (mode) {
        case STORE_BUFFER_ONLY:
          ASSERT(GetMode(stub) == INCREMENTAL ||
                 GetMode(stub) == INCREMENTAL_COMPACTION);
          PatchBranchIntoNop(&masm, 0);
          PatchBranchIntoNop(&masm, 2 * Assembler::kInstrSize);
          break;
        case INCREMENTAL:
          ASSERT(GetMode(stub) == STORE_BUFFER_ONLY);
          PatchNopIntoBranch(&masm, 0);
          break;
        case INCREMENTAL_COMPACTION:
          ASSERT(GetMode(stub) == STORE_BUFFER_ONLY);
          PatchNopIntoBranch(&masm, 2 * Assembler::kInstrSize);
          break;
      }
      ASSERT(GetMode(stub) == mode);
      CpuFeatures::FlushICache(stub->instruction_start(),
                               4 * Assembler::kInstrSize);
    }
  
   private:
    // This is a helper class for freeing up 3 scratch registers.  The input is
    // two registers that must be preserved and one scratch register provided by
    // the caller.
    class RegisterAllocation {
     public:
      RegisterAllocation(Register object,
                         Register address,
                         Register scratch0)
          : object_(object),
            address_(address),
            scratch0_(scratch0) {
        ASSERT(!AreAliased(scratch0, object, address, no_reg));
        scratch1_ = GetRegisterThatIsNotOneOf(object_, address_, scratch0_);
      }
  
      void Save(MacroAssembler* masm) {
        ASSERT(!AreAliased(object_, address_, scratch1_, scratch0_));
        // We don't have to save scratch0_ because it was given to us as
        // a scratch register.
        masm->push(scratch1_);
      }
  
      void Restore(MacroAssembler* masm) {
        masm->pop(scratch1_);
      }
  
      // If we have to call into C then we need to save and restore all caller-
      // saved registers that were not already preserved.  The scratch registers
      // will be restored by other means so we don't bother pushing them here.
      void SaveCallerSaveRegisters(MacroAssembler* masm, SaveFPRegsMode mode) {
        masm->MultiPush((kJSCallerSaved | ra.bit()) & ~scratch1_.bit());
        if (mode == kSaveFPRegs) {
          masm->MultiPushFPU(kCallerSavedFPU);
        }
      }
  
      inline void RestoreCallerSaveRegisters(MacroAssembler*masm,
                                             SaveFPRegsMode mode) {
        if (mode == kSaveFPRegs) {
          masm->MultiPopFPU(kCallerSavedFPU);
        }
        masm->MultiPop((kJSCallerSaved | ra.bit()) & ~scratch1_.bit());
      }
  
      inline Register object() { return object_; }
      inline Register address() { return address_; }
      inline Register scratch0() { return scratch0_; }
      inline Register scratch1() { return scratch1_; }
  
     private:
      Register object_;
      Register address_;
      Register scratch0_;
      Register scratch1_;
  
      friend class RecordWriteStub;
    };
  
    enum OnNoNeedToInformIncrementalMarker {
      kReturnOnNoNeedToInformIncrementalMarker,
      kUpdateRememberedSetOnNoNeedToInformIncrementalMarker
    };
  
    void Generate(MacroAssembler* masm);
    void GenerateIncremental(MacroAssembler* masm, Mode mode);
    void CheckNeedsToInformIncrementalMarker(
        MacroAssembler* masm,
        OnNoNeedToInformIncrementalMarker on_no_need,
        Mode mode);
    void InformIncrementalMarker(MacroAssembler* masm);
  
    Major MajorKey() const { return RecordWrite; }
  
    int MinorKey() const {
      return ObjectBits::encode(object_.code()) |
          ValueBits::encode(value_.code()) |
          AddressBits::encode(address_.code()) |
          RememberedSetActionBits::encode(remembered_set_action_) |
          SaveFPRegsModeBits::encode(save_fp_regs_mode_);
    }
  
    void Activate(Code* code) {
      code->GetHeap()->incremental_marking()->ActivateGeneratedStub(code);
    }
  
    class ObjectBits: public BitField<int, 0, 5> {};
    class ValueBits: public BitField<int, 5, 5> {};
    class AddressBits: public BitField<int, 10, 5> {};
    class RememberedSetActionBits: public BitField<RememberedSetAction, 15, 1> {};
    class SaveFPRegsModeBits: public BitField<SaveFPRegsMode, 16, 1> {};
  
    Register object_;
    Register value_;
    Register address_;
    RememberedSetAction remembered_set_action_;
    SaveFPRegsMode save_fp_regs_mode_;
    Label slow_;
    RegisterAllocation regs_;
  };
  
  
  // Trampoline stub to call into native code. To call safely into native code
  // in the presence of compacting GC (which can move code objects) we need to
  // keep the code which called into native pinned in the memory. Currently the
  // simplest approach is to generate such stub early enough so it can never be
  // moved by GC
  class DirectCEntryStub: public PlatformCodeStub {
   public:
    explicit DirectCEntryStub(Isolate* isolate) : PlatformCodeStub(isolate) {}
    void Generate(MacroAssembler* masm);
    void GenerateCall(MacroAssembler* masm, Register target);
  
   private:
    Major MajorKey() const { return DirectCEntry; }
    int MinorKey() const { return 0; }
  
    bool NeedsImmovableCode() { return true; }
  };
  
  
  class NameDictionaryLookupStub: public PlatformCodeStub {
   public:
    enum LookupMode { POSITIVE_LOOKUP, NEGATIVE_LOOKUP };
  
    NameDictionaryLookupStub(Isolate* isolate, LookupMode mode)
        : PlatformCodeStub(isolate), mode_(mode) { }
  
    void Generate(MacroAssembler* masm);
  
    static void GenerateNegativeLookup(MacroAssembler* masm,
                                       Label* miss,
                                       Label* done,
                                       Register receiver,
                                       Register properties,
                                       Handle<Name> name,
                                       Register scratch0);
  
    static void GeneratePositiveLookup(MacroAssembler* masm,
                                       Label* miss,
                                       Label* done,
                                       Register elements,
                                       Register name,
                                       Register r0,
                                       Register r1);
  
    virtual bool SometimesSetsUpAFrame() { return false; }
  
   private:
    static const int kInlinedProbes = 4;
    static const int kTotalProbes = 20;
  
    static const int kCapacityOffset =
        NameDictionary::kHeaderSize +
        NameDictionary::kCapacityIndex * kPointerSize;
  
    static const int kElementsStartOffset =
        NameDictionary::kHeaderSize +
        NameDictionary::kElementsStartIndex * kPointerSize;
  
    Major MajorKey() const { return NameDictionaryLookup; }
  
    int MinorKey() const { return LookupModeBits::encode(mode_); }
  
    class LookupModeBits: public BitField<LookupMode, 0, 1> {};
  
    LookupMode mode_;
  };
  
  
  } }  // namespace v8::internal
  
  #endif  // V8_MIPS_CODE_STUBS_ARM_H_
  