/*
 * Copyright (c) 2016, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 *
 */

#include "precompiled.hpp"
#include "asm/macroAssembler.inline.hpp"
#include "gc/shared/barrierSet.hpp"
#include "gc/shared/cardTable.hpp"
#include "gc/shared/cardTableModRefBS.hpp"
#include "gc/shared/cardTableModRefBSCodeGen.hpp"
#include "gc/shared/collectedHeap.hpp"
#include "interpreter/interp_masm.hpp"

#define __ masm->

#ifdef PRODUCT
#define BLOCK_COMMENT(str) /* nothing */
#else
#define BLOCK_COMMENT(str) __ block_comment(str)
#endif

#define BIND(label) bind(label); BLOCK_COMMENT(#label ":")

void CardTableModRefBSCodeGen::gen_write_ref_array_post_barrier(MacroAssembler* masm, DecoratorSet decorators, Register addr, Register count, Register tmp) {
  CardTableModRefBS* ct = barrier_set_cast<CardTableModRefBS>(Universe::heap()->barrier_set());
  assert(sizeof(*ct->card_table()->byte_map_base()) == sizeof(jbyte), "adjust this code");
  assert_different_registers(addr, count, tmp);

  Label L_loop;

  __ sll_ptr(count, LogBytesPerHeapOop, count);
  __ sub(count, BytesPerHeapOop, count);
  __ add(count, addr, count);
  // Use two shifts to clear out those low order two bits! (Cannot opt. into 1.)
  __ srl_ptr(addr, CardTable::card_shift, addr);
  __ srl_ptr(count, CardTable::card_shift, count);
  __ sub(count, addr, count);
  AddressLiteral rs((address)ct->card_table()->byte_map_base());
  __ set(rs, tmp);
  __ BIND(L_loop);
  __ stb(G0, tmp, addr);
  __ subcc(count, 1, count);
  __ brx(Assembler::greaterEqual, false, Assembler::pt, L_loop);
  __ delayed()->add(addr, 1, addr);
}

void CardTableModRefBSCodeGen::card_table_write(MacroAssembler* masm,
                                                jbyte* byte_map_base,
                                                Register tmp, Register obj) {
#ifdef _LP64
  __ srlx(obj, CardTable::card_shift, obj);
#else
  __ srl(obj, CardTable::card_shift, obj);
#endif
  assert(tmp != obj, "need separate temp reg");
  __ set((address) byte_map_base, tmp);
  __ stb(G0, tmp, obj);
}

void CardTableModRefBSCodeGen::card_write_barrier_post(MacroAssembler* masm, Register store_addr, Register new_val, Register tmp) {
  // If we're writing constant NULL, we can skip the write barrier.
  if (new_val == G0) return;
  CardTableModRefBS* bs =
    barrier_set_cast<CardTableModRefBS>(Universe::heap()->barrier_set());
  card_table_write(masm, bs->card_table()->byte_map_base(), tmp, store_addr);
}

void CardTableModRefBSCodeGen::oop_store_at(MacroAssembler* masm, DecoratorSet decorators, BasicType type,
                                            Register base, Register index, int offset, Register val, Register tmp) {
  bool on_array = (decorators & ACCESS_ON_ARRAY) != 0;
  bool on_anonymous = (decorators & ACCESS_ON_ANONYMOUS) != 0;
  bool precise = on_array || on_anonymous;
  BarrierSetCodeGen::store_at(masm, decorators, type, base, index, offset, val, tmp);
  // No need for post barrier if storing NULL
  if (val != G0) {
    if (precise) {
      if (index == noreg) {
        __ add(base, offset, base);
      } else {
        __ add(base, index, base);
      }
    }
    card_write_barrier_post(masm, base, val, tmp);
  }
}