void G1BarrierSetAssembler::g1_write_barrier_pre(MacroAssembler* masm, DecoratorSet decorators, Register obj, RegisterOrConstant ind_or_offs, Register pre_val,

                                                 Register tmp1, Register tmp2, bool needs_frame) {

  bool not_null  = (decorators & OOP_NOT_NULL) != 0,

       preloaded = obj == noreg;

  Register nv_save = noreg;

  if (preloaded) {

    // We are not loading the previous value so make

    // sure that we don't trash the value in pre_val

    // with the code below.

    assert_different_registers(pre_val, tmp1, tmp2);

    if (pre_val->is_volatile()) {

      nv_save = !tmp1->is_volatile() ? tmp1 : tmp2;

      assert(!nv_save->is_volatile(), "need one nv temp register if pre_val lives in volatile register");

    }

  }

  Label runtime, filtered;

  // Is marking active?

  if (in_bytes(SATBMarkQueue::byte_width_of_active()) == 4) {

    __ lwz(tmp1, in_bytes(JavaThread::satb_mark_queue_offset() + SATBMarkQueue::byte_offset_of_active()), R16_thread);

  } else {

    guarantee(in_bytes(SATBMarkQueue::byte_width_of_active()) == 1, "Assumption");

    __ lbz(tmp1, in_bytes(JavaThread::satb_mark_queue_offset() + SATBMarkQueue::byte_offset_of_active()), R16_thread);

  }

  __ cmpdi(CCR0, tmp1, 0);

  __ beq(CCR0, filtered);

  // Do we need to load the previous value?

  if (!preloaded) {

    // Load the previous value...

    if (UseCompressedOops) {

      __ lwz(pre_val, ind_or_offs, obj);

    } else {

      __ ld(pre_val, ind_or_offs, obj);

    }

    // Previous value has been loaded into Rpre_val.

  }

  assert(pre_val != noreg, "must have a real register");

  // Is the previous value null?

  if (preloaded && not_null) {

#ifdef ASSERT

    __ cmpdi(CCR0, pre_val, 0);

    __ asm_assert_ne("null oop not allowed (G1 pre)", 0x321); // Checked by caller.

#endif

  } else {

    __ cmpdi(CCR0, pre_val, 0);

    __ beq(CCR0, filtered);

  }

  if (!preloaded && UseCompressedOops) {

    __ decode_heap_oop_not_null(pre_val);

  }

  // OK, it's not filtered, so we'll need to call enqueue. In the normal

  // case, pre_val will be a scratch G-reg, but there are some cases in

  // which it's an O-reg. In the first case, do a normal call. In the

  // latter, do a save here and call the frameless version.

  // Can we store original value in the thread's buffer?

  // Is index == 0?

  // (The index field is typed as size_t.)

  const Register Rbuffer = tmp1, Rindex = tmp2;

  __ ld(Rindex, in_bytes(JavaThread::satb_mark_queue_offset() + SATBMarkQueue::byte_offset_of_index()), R16_thread);

  __ cmpdi(CCR0, Rindex, 0);

  __ beq(CCR0, runtime); // If index == 0, goto runtime.

  __ ld(Rbuffer, in_bytes(JavaThread::satb_mark_queue_offset() + SATBMarkQueue::byte_offset_of_buf()), R16_thread);

  __ addi(Rindex, Rindex, -wordSize); // Decrement index.

  __ std(Rindex, in_bytes(JavaThread::satb_mark_queue_offset() + SATBMarkQueue::byte_offset_of_index()), R16_thread);

  // Record the previous value.

  __ stdx(pre_val, Rbuffer, Rindex);

  __ b(filtered);

  __ bind(runtime);

  // May need to preserve LR. Also needed if current frame is not compatible with C calling convention.

  if (needs_frame) {

    __ save_LR_CR(tmp1);

    __ push_frame_reg_args(0, tmp2);

  }

  if (pre_val->is_volatile() && preloaded) { __ mr(nv_save, pre_val); } // Save pre_val across C call if it was preloaded.

  __ call_VM_leaf(CAST_FROM_FN_PTR(address, SharedRuntime::g1_wb_pre), pre_val, R16_thread);

  if (pre_val->is_volatile() && preloaded) { __ mr(pre_val, nv_save); } // restore

  if (needs_frame) {

    __ pop_frame();

    __ restore_LR_CR(tmp1);

  }

  __ bind(filtered);

}

void G1BarrierSetAssembler::g1_write_barrier_post(MacroAssembler* masm, DecoratorSet decorators, Register store_addr, Register new_val,

                                                  Register tmp1, Register tmp2, Register tmp3) {

  bool not_null = (decorators & OOP_NOT_NULL) != 0;

  Label runtime, filtered;

  assert_different_registers(store_addr, new_val, tmp1, tmp2);

  CardTableBarrierSet* ct = barrier_set_cast<CardTableBarrierSet>(Universe::heap()->barrier_set());

  assert(sizeof(*ct->card_table()->byte_map_base()) == sizeof(jbyte), "adjust this code");

  // Does store cross heap regions?

  if (G1RSBarrierRegionFilter) {

    __ xorr(tmp1, store_addr, new_val);

    __ srdi_(tmp1, tmp1, HeapRegion::LogOfHRGrainBytes);

    __ beq(CCR0, filtered);

  }

  // Crosses regions, storing NULL?

  if (not_null) {

#ifdef ASSERT

    __ cmpdi(CCR0, new_val, 0);

    __ asm_assert_ne("null oop not allowed (G1 post)", 0x322); // Checked by caller.

#endif

  } else {

    __ cmpdi(CCR0, new_val, 0);

    __ beq(CCR0, filtered);

  }

  // Storing region crossing non-NULL, is card already dirty?

  const Register Rcard_addr = tmp1;

  Register Rbase = tmp2;

  __ load_const_optimized(Rbase, (address)(ct->card_table()->byte_map_base()), /*temp*/ tmp3);

  __ srdi(Rcard_addr, store_addr, CardTable::card_shift);

  // Get the address of the card.

  __ lbzx(/*card value*/ tmp3, Rbase, Rcard_addr);

  __ cmpwi(CCR0, tmp3, (int)G1CardTable::g1_young_card_val());

  __ beq(CCR0, filtered);

  __ membar(Assembler::StoreLoad);

  __ lbzx(/*card value*/ tmp3, Rbase, Rcard_addr);  // Reload after membar.

  __ cmpwi(CCR0, tmp3 /* card value */, (int)G1CardTable::dirty_card_val());

  __ beq(CCR0, filtered);

  // Storing a region crossing, non-NULL oop, card is clean.

  // Dirty card and log.

  __ li(tmp3, (int)G1CardTable::dirty_card_val());

  //release(); // G1: oops are allowed to get visible after dirty marking.

  __ stbx(tmp3, Rbase, Rcard_addr);

  __ add(Rcard_addr, Rbase, Rcard_addr); // This is the address which needs to get enqueued.

  Rbase = noreg; // end of lifetime

  const Register Rqueue_index = tmp2,

                 Rqueue_buf   = tmp3;

  __ ld(Rqueue_index, in_bytes(JavaThread::dirty_card_queue_offset() + DirtyCardQueue::byte_offset_of_index()), R16_thread);

  __ cmpdi(CCR0, Rqueue_index, 0);

  __ beq(CCR0, runtime); // index == 0 then jump to runtime

  __ ld(Rqueue_buf, in_bytes(JavaThread::dirty_card_queue_offset() + DirtyCardQueue::byte_offset_of_buf()), R16_thread);

  __ addi(Rqueue_index, Rqueue_index, -wordSize); // decrement index

  __ std(Rqueue_index, in_bytes(JavaThread::dirty_card_queue_offset() + DirtyCardQueue::byte_offset_of_index()), R16_thread);

  __ stdx(Rcard_addr, Rqueue_buf, Rqueue_index); // store card

  __ b(filtered);

  __ bind(runtime);

  // Save the live input values.

  __ call_VM_leaf(CAST_FROM_FN_PTR(address, SharedRuntime::g1_wb_post), Rcard_addr, R16_thread);

  __ bind(filtered);

}

void G1BarrierSetAssembler::oop_store_at(MacroAssembler* masm, DecoratorSet decorators, BasicType type,

                                       Register base, RegisterOrConstant ind_or_offs, Register val,

                                       Register tmp1, Register tmp2, Register tmp3, bool needs_frame) {

  bool on_array = (decorators & IN_HEAP_ARRAY) != 0;

  bool on_anonymous = (decorators & ON_UNKNOWN_OOP_REF) != 0;

  bool precise = on_array || on_anonymous;

  // Load and record the previous value.

  g1_write_barrier_pre(masm, decorators, base, ind_or_offs,

                       tmp1, tmp2, tmp3, needs_frame);

  BarrierSetAssembler::store_at(masm, decorators, type, base, ind_or_offs, val, tmp1, tmp2, tmp3, needs_frame);

  // No need for post barrier if storing NULL

  if (val != noreg) {

    if (precise) {

      if (ind_or_offs.is_constant()) {

        __ add_const_optimized(base, base, ind_or_offs.as_constant(), tmp1);

      } else {

        __ add(base, ind_or_offs.as_register(), base);

      }

    }

    g1_write_barrier_post(masm, decorators, base, val, tmp1, tmp2, tmp3);

  }

}

void G1BarrierSetAssembler::load_at(MacroAssembler* masm, DecoratorSet decorators, BasicType type,

                                    Register base, RegisterOrConstant ind_or_offs, Register dst,

                                    Register tmp1, Register tmp2, bool needs_frame, Label *is_null) {

  bool on_oop = type == T_OBJECT || type == T_ARRAY;

  bool on_weak = (decorators & ON_WEAK_OOP_REF) != 0;

  bool on_phantom = (decorators & ON_PHANTOM_OOP_REF) != 0;

  bool on_reference = on_weak || on_phantom;

  Label done;

  if (on_oop && on_reference && is_null == NULL) { is_null = &done; }

  // Load the value of the referent field.

  ModRefBarrierSetAssembler::load_at(masm, decorators, type, base, ind_or_offs, dst, tmp1, tmp2, needs_frame, is_null);

  if (on_oop && on_reference) {

    // Generate the G1 pre-barrier code to log the value of

    // the referent field in an SATB buffer. Note with

    // these parameters the pre-barrier does not generate

    // the load of the previous value

    // We only reach here if value is not null.

    g1_write_barrier_pre(masm, decorators | OOP_NOT_NULL, noreg /* obj */, (intptr_t)0, dst /* pre_val */,

                         tmp1, tmp2, needs_frame);

  }

  __ bind(done);

}

void G1BarrierSetAssembler::resolve_jobject(MacroAssembler* masm, Register value, Register tmp1, Register tmp2, bool needs_frame) {

  Label done, not_weak;

  __ cmpdi(CCR0, value, 0);

  __ beq(CCR0, done);         // Use NULL as-is.

  __ clrrdi(tmp1, value, JNIHandles::weak_tag_size);

  __ andi_(tmp2, value, JNIHandles::weak_tag_mask);

  __ ld(value, 0, tmp1);      // Resolve (untagged) jobject.

  __ beq(CCR0, not_weak);     // Test for jweak tag.

  __ verify_oop(value);

  g1_write_barrier_pre(masm, IN_ROOT | ON_PHANTOM_OOP_REF,

                       noreg, noreg, value,

                       tmp1, tmp2, needs_frame);

  __ bind(not_weak);

  __ verify_oop(value);

  __ bind(done);

}

#undef __