/*

 * Copyright (c) 2005, 2010, 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 "c1/c1_FpuStackSim.hpp"

#include "c1/c1_FrameMap.hpp"

#include "utilities/array.hpp"

#include "utilities/ostream.hpp"

//--------------------------------------------------------

//               FpuStackSim

//--------------------------------------------------------

// This class maps the FPU registers to their stack locations; it computes

// the offsets between individual registers and simulates the FPU stack.

const int EMPTY = -1;

int FpuStackSim::regs_at(int i) const {

  assert(i >= 0 && i < FrameMap::nof_fpu_regs, "out of bounds");

  return _regs[i];

}

void FpuStackSim::set_regs_at(int i, int val) {

  assert(i >= 0 && i < FrameMap::nof_fpu_regs, "out of bounds");

  _regs[i] = val;

}

void FpuStackSim::dec_stack_size() {

  _stack_size--;

  assert(_stack_size >= 0, "FPU stack underflow");

}

void FpuStackSim::inc_stack_size() {

  _stack_size++;

  assert(_stack_size <= FrameMap::nof_fpu_regs, "FPU stack overflow");

}

FpuStackSim::FpuStackSim(Compilation* compilation)

 : _compilation(compilation)

{

  _stack_size = 0;

  for (int i = 0; i < FrameMap::nof_fpu_regs; i++) {

    set_regs_at(i, EMPTY);

  }

}

void FpuStackSim::pop() {

  if (TraceFPUStack) { tty->print("FPU-pop "); print(); tty->cr(); }

  set_regs_at(tos_index(), EMPTY);

  dec_stack_size();

}

void FpuStackSim::pop(int rnr) {

  if (TraceFPUStack) { tty->print("FPU-pop %d", rnr); print(); tty->cr(); }

  assert(regs_at(tos_index()) == rnr, "rnr is not on TOS");

  set_regs_at(tos_index(), EMPTY);

  dec_stack_size();

}

void FpuStackSim::push(int rnr) {

  if (TraceFPUStack) { tty->print("FPU-push %d", rnr); print(); tty->cr(); }

  assert(regs_at(stack_size()) == EMPTY, "should be empty");

  set_regs_at(stack_size(), rnr);

  inc_stack_size();

}

void FpuStackSim::swap(int offset) {

  if (TraceFPUStack) { tty->print("FPU-swap %d", offset); print(); tty->cr(); }

  int t = regs_at(tos_index() - offset);

  set_regs_at(tos_index() - offset, regs_at(tos_index()));

  set_regs_at(tos_index(), t);

}

int FpuStackSim::offset_from_tos(int rnr) const {

  for (int i = tos_index(); i >= 0; i--) {

    if (regs_at(i) == rnr) {

      return tos_index() - i;

    }

  }

  assert(false, "FpuStackSim: register not found");

  BAILOUT_("FpuStackSim: register not found", 0);

}

int FpuStackSim::get_slot(int tos_offset) const {

  return regs_at(tos_index() - tos_offset);

}

void FpuStackSim::set_slot(int tos_offset, int rnr) {

  set_regs_at(tos_index() - tos_offset, rnr);

}

void FpuStackSim::rename(int old_rnr, int new_rnr) {

  if (TraceFPUStack) { tty->print("FPU-rename %d %d", old_rnr, new_rnr); print(); tty->cr(); }

  if (old_rnr == new_rnr)

    return;

  bool found = false;

  for (int i = 0; i < stack_size(); i++) {

    assert(regs_at(i) != new_rnr, "should not see old occurrences of new_rnr on the stack");

    if (regs_at(i) == old_rnr) {

      set_regs_at(i, new_rnr);

      found = true;

    }

  }

  assert(found, "should have found at least one instance of old_rnr");

}

bool FpuStackSim::contains(int rnr) {

  for (int i = 0; i < stack_size(); i++) {

    if (regs_at(i) == rnr) {

      return true;

    }

  }

  return false;

}

bool FpuStackSim::is_empty() {

#ifdef ASSERT

  if (stack_size() == 0) {

    for (int i = 0; i < FrameMap::nof_fpu_regs; i++) {

      assert(regs_at(i) == EMPTY, "must be empty");

    }

  }

#endif

  return stack_size() == 0;

}

bool FpuStackSim::slot_is_empty(int tos_offset) {

  return (regs_at(tos_index() - tos_offset) == EMPTY);

}

void FpuStackSim::clear() {

  if (TraceFPUStack) { tty->print("FPU-clear"); print(); tty->cr(); }

  for (int i = tos_index(); i >= 0; i--) {

    set_regs_at(i, EMPTY);

  }

  _stack_size = 0;

}

intArray* FpuStackSim::write_state() {

  intArray* res = new intArray(1 + FrameMap::nof_fpu_regs);

  (*res)[0] = stack_size();

  for (int i = 0; i < FrameMap::nof_fpu_regs; i++) {

    (*res)[1 + i] = regs_at(i);

  }

  return res;

}

void FpuStackSim::read_state(intArray* fpu_stack_state) {

  _stack_size = (*fpu_stack_state)[0];

  for (int i = 0; i < FrameMap::nof_fpu_regs; i++) {

    set_regs_at(i, (*fpu_stack_state)[1 + i]);

  }

}

#ifndef PRODUCT

void FpuStackSim::print() {

  tty->print(" N=%d[", stack_size());\

  for (int i = 0; i < stack_size(); i++) {

    int reg = regs_at(i);

    if (reg != EMPTY) {

      tty->print("%d", reg);

    } else {

      tty->print("_");

    }

  };

  tty->print(" ]");

}

#endif