/*

 * 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.

 *

 *

 */

//  Simulates the FPU stack and maintains mapping [fpu-register -> stack offset]

//  FPU registers are described as numbers from 0..nof_fpu_regs-1

class Compilation;

class FpuStackSim VALUE_OBJ_CLASS_SPEC {

 private:

  Compilation* _compilation;

  int          _stack_size;

  int          _regs[FrameMap::nof_fpu_regs];

  int tos_index() const                        { return _stack_size - 1; }

  int regs_at(int i) const;

  void set_regs_at(int i, int val);

  void dec_stack_size();

  void inc_stack_size();

  // unified bailout support

  Compilation*  compilation() const              { return _compilation; }

  void          bailout(const char* msg) const   { compilation()->bailout(msg); }

  bool          bailed_out() const               { return compilation()->bailed_out(); }

 public:

  FpuStackSim(Compilation* compilation);

  void pop ();

  void pop (int rnr);                          // rnr must be on tos

  void push(int rnr);

  void swap(int offset);                       // exchange tos with tos + offset

  int offset_from_tos(int rnr) const;          // return the offset of the topmost instance of rnr from TOS

  int  get_slot(int tos_offset) const;         // return the entry at the given offset from TOS

  void set_slot(int tos_offset, int rnr);      // set the entry at the given offset from TOS

  void rename(int old_rnr, int new_rnr);       // rename all instances of old_rnr to new_rnr

  bool contains(int rnr);                      // debugging support only

  bool is_empty();

  bool slot_is_empty(int tos_offset);

  int stack_size() const                       { return _stack_size; }

  void clear();

  intArray* write_state();

  void read_state(intArray* fpu_stack_state);

  void print() PRODUCT_RETURN;

};