/*
 *  This file is part of the Jikes RVM project (http://jikesrvm.org).
 *
 *  This file is licensed to You under the Eclipse Public License (EPL);
 *  You may not use this file except in compliance with the License. You
 *  may obtain a copy of the License at
 *
 *      http://www.opensource.org/licenses/eclipse-1.0.php
 *
 *  See the COPYRIGHT.txt file distributed with this work for information
 *  regarding copyright ownership.
 */
package org.jikesrvm.osr.bytecodes;

import static org.jikesrvm.classloader.BytecodeConstants.JBC_impdep1;
import static org.jikesrvm.classloader.BytecodeConstants.JBC_wide;
import static org.jikesrvm.runtime.JavaSizeConstants.LOG_BITS_IN_BYTE;
import static org.jikesrvm.runtime.UnboxedSizeConstants.BYTES_IN_ADDRESS;

import org.vmmagic.unboxed.Word;

/**
 * OSR_PseudoBytecode is super class of all pseudo instructions.
 */
public abstract class PseudoBytecode {

  public PseudoBytecode next;

  public abstract byte[] getBytes();

  public abstract int getSize();

  public abstract int stackChanges();

  public static byte[] initBytes(int size, int instruction) {
    byte[] code = new byte[size];
    code[0] = (byte) JBC_impdep1;
    code[1] = (byte) instruction;
    return code;
  }

  public static void int2bytes(byte[] to, int p, int value) {

    for (int i = 3; i >= 0; i--) {
      to[p++] = (byte) ((value >>> (i << LOG_BITS_IN_BYTE)) & 0x0FF);
    }
  }

  public static void long2bytes(byte[] to, int p, long value) {

    for (int i = 7; i >= 0; i--) {
      to[p++] = (byte) ((value >>> (i << LOG_BITS_IN_BYTE)) & 0x0FF);
    }
  }

  public static void word2bytes(byte[] to, int p, Word value) {

    for (int i = BYTES_IN_ADDRESS - 1; i >= 0; i--) {
      to[p++] = (byte) (value.rshl(i << LOG_BITS_IN_BYTE).toInt() & 0x0FF);
    }
  }

  public static void float2bytes(byte[] to, int p, float value) {

    int v = Float.floatToIntBits(value);
    int2bytes(to, p, v);
  }

  public static void double2bytes(byte[] to, int p, double value) {

    long v = Double.doubleToLongBits(value);
    long2bytes(to, p, v);
  }

  public static byte[] makeOUUcode(int op, int idx) {

    byte[] codes = new byte[3];
    codes[0] = (byte) op;
    codes[1] = (byte) ((idx >> 8) & 0x0FF);
    codes[2] = (byte) (idx & 0x0FF);

    return codes;
  }

  public static byte[] makeWOUUcode(int op, int idx) {
    byte[] codes = new byte[4];
    codes[0] = (byte) JBC_wide;
    codes[1] = (byte) op;
    codes[2] = (byte) ((idx >> 8) & 0x0FF);
    codes[3] = (byte) (idx & 0x0FF);
    return codes;
  }

  public static byte[] makeOUcode(int op, int idx) {
    byte[] codes = new byte[2];
    codes[0] = (byte) op;
    codes[1] = (byte) (idx & 0x0FF);
    return codes;
  }
}