/*

 * Copyright 2000-2006 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 *

 */

package sun.jvm.hotspot.compiler;

import java.util.*;

import sun.jvm.hotspot.code.*;

import sun.jvm.hotspot.runtime.*;

import sun.jvm.hotspot.types.*;

import sun.jvm.hotspot.utilities.*;

public class OopMapValue {

  private short value;

  private short contentReg;

  /** Read from target VM; located in compiler/oopMap.hpp */

  // How bits are organized

  static int TYPE_BITS;

  static int REGISTER_BITS;

  static int TYPE_SHIFT;

  static int REGISTER_SHIFT;

  static int TYPE_MASK;

  static int TYPE_MASK_IN_PLACE;

  static int REGISTER_MASK;

  static int REGISTER_MASK_IN_PLACE;

  // Types of OopValues

  static int UNUSED_VALUE;

  static int OOP_VALUE;

  static int VALUE_VALUE;

  static int CALLEE_SAVED_VALUE;

  static int DERIVED_OOP_VALUE;

  static {

    VM.registerVMInitializedObserver(new Observer() {

        public void update(Observable o, Object data) {

          initialize(VM.getVM().getTypeDataBase());

        }

      });

  }

  private static void initialize(TypeDataBase db) {

    TYPE_BITS              = db.lookupIntConstant("OopMapValue::type_bits").intValue();

    REGISTER_BITS          = db.lookupIntConstant("OopMapValue::register_bits").intValue();

    TYPE_SHIFT             = db.lookupIntConstant("OopMapValue::type_shift").intValue();

    REGISTER_SHIFT         = db.lookupIntConstant("OopMapValue::register_shift").intValue();

    TYPE_MASK              = db.lookupIntConstant("OopMapValue::type_mask").intValue();

    TYPE_MASK_IN_PLACE     = db.lookupIntConstant("OopMapValue::type_mask_in_place").intValue();

    REGISTER_MASK          = db.lookupIntConstant("OopMapValue::register_mask").intValue();

    REGISTER_MASK_IN_PLACE = db.lookupIntConstant("OopMapValue::register_mask_in_place").intValue();

    UNUSED_VALUE           = db.lookupIntConstant("OopMapValue::unused_value").intValue();

    OOP_VALUE              = db.lookupIntConstant("OopMapValue::oop_value").intValue();

    VALUE_VALUE            = db.lookupIntConstant("OopMapValue::value_value").intValue();

    CALLEE_SAVED_VALUE     = db.lookupIntConstant("OopMapValue::callee_saved_value").intValue();

    DERIVED_OOP_VALUE      = db.lookupIntConstant("OopMapValue::derived_oop_value").intValue();

  }

  public static abstract class OopTypes {

    public static final OopTypes UNUSED_VALUE       = new OopTypes() { int getValue() { return OopMapValue.UNUSED_VALUE;       }};

    public static final OopTypes OOP_VALUE          = new OopTypes() { int getValue() { return OopMapValue.OOP_VALUE;          }};

    public static final OopTypes VALUE_VALUE        = new OopTypes() { int getValue() { return OopMapValue.VALUE_VALUE;        }};

    public static final OopTypes CALLEE_SAVED_VALUE = new OopTypes() { int getValue() { return OopMapValue.CALLEE_SAVED_VALUE; }};

    public static final OopTypes DERIVED_OOP_VALUE  = new OopTypes() { int getValue() { return OopMapValue.DERIVED_OOP_VALUE;  }};

    abstract int getValue();

    protected OopTypes() {}

  }

  public OopMapValue()                                  { setValue((short) 0); setContentReg(new VMReg(0)); }

  public OopMapValue(VMReg reg, OopTypes t)             { setReg(reg); setType(t);                      }

  public OopMapValue(VMReg reg, OopTypes t, VMReg reg2) { setReg(reg); setType(t); setContentReg(reg2); }

  public OopMapValue(CompressedReadStream stream)       { readFrom(stream);                             }

  public void readFrom(CompressedReadStream stream) {

    setValue((short) stream.readInt());

    if (isCalleeSaved() || isDerivedOop()) {

      setContentReg(new VMReg(stream.readInt()));

    }

  }

  // Querying

  public boolean isOop()         { return (getValue() & TYPE_MASK_IN_PLACE) == OOP_VALUE;          }

  public boolean isValue()       { return (getValue() & TYPE_MASK_IN_PLACE) == VALUE_VALUE;        }

  public boolean isCalleeSaved() { return (getValue() & TYPE_MASK_IN_PLACE) == CALLEE_SAVED_VALUE; }

  public boolean isDerivedOop()  { return (getValue() & TYPE_MASK_IN_PLACE) == DERIVED_OOP_VALUE;  }

  public VMReg getReg() { return new VMReg((getValue() & REGISTER_MASK_IN_PLACE) >> REGISTER_SHIFT); }

  public void  setReg(VMReg r) { setValue((short) (r.getValue() << REGISTER_SHIFT | (getValue() & TYPE_MASK_IN_PLACE))); }

  public OopTypes getType() {

    int which = (getValue() & TYPE_MASK_IN_PLACE);

         if (which == UNUSED_VALUE) return OopTypes.UNUSED_VALUE;

    else if (which == OOP_VALUE)    return OopTypes.OOP_VALUE;

    else if (which == VALUE_VALUE)  return OopTypes.VALUE_VALUE;

    else if (which == CALLEE_SAVED_VALUE) return OopTypes.CALLEE_SAVED_VALUE;

    else if (which == DERIVED_OOP_VALUE)  return OopTypes.DERIVED_OOP_VALUE;

    else throw new InternalError("unknown which " + which + " (TYPE_MASK_IN_PLACE = " + TYPE_MASK_IN_PLACE + ")");

  }

  public void setType(OopTypes t) { setValue((short) ((getValue() & REGISTER_MASK_IN_PLACE) | t.getValue())); }

  public VMReg getContentReg()        { return new VMReg(contentReg); }

  public void  setContentReg(VMReg r) { contentReg = (short) r.getValue(); }

  /** Physical location queries */

  public boolean isRegisterLoc()      { return (getReg().lessThan(VM.getVM().getVMRegImplInfo().getStack0())); }

  public boolean isStackLoc()         { return (getReg().greaterThanOrEqual(VM.getVM().getVMRegImplInfo().getStack0())); }

  /** Returns offset from sp. */

  public int getStackOffset() {

    if (Assert.ASSERTS_ENABLED) {

      Assert.that(isStackLoc(), "must be stack location");

    }

    return getReg().minus(VM.getVM().getVMRegImplInfo().getStack0());

  }

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

  // Internals only below this point

  //

  private void setValue(short value) {

    this.value = value;

  }

  private int getValue() {

    return value;

  }

}