/* Software Name : AsmDex
* Version : 1.0
*
* Copyright © 2012 France Télécom
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the copyright holders nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
* THE POSSIBILITY OF SUCH DAMAGE.
*/
package org.ow2.asmdex.instruction;
import org.ow2.asmdex.lowLevelUtils.ByteVector;
import org.ow2.asmdex.lowLevelUtils.IDalvikValueReader;
import org.ow2.asmdex.structureWriter.ConstantPool;
/**
* Encodes and decodes an instruction built with the Dalvik format 22B.
*
* @author Julien Névo
*/
public class InstructionFormat22B extends Instruction
implements ITwoRegistersInstruction, ILiteralInstruction {
private static final int INSTRUCTION_SIZE = 4; // Instruction size in bytes.
private int registerA;
private int registerB;
private int literalC;
@Override
public int getRegisterA() {
return registerA;
}
@Override
public int getRegisterB() {
return registerB;
}
@Override
public int getLiteral() {
return literalC;
}
/**
* Constructor of the Instruction, using a Reader to parse its bytecode.
* @param reader reader on the Instruction to parse, pointing after the 16-bit opcode.
* @param opcode 16-bit opcode.
*/
// public InstructionFormat22B(IDalvikValueReader reader, int opcode) {
// super(opcode);
//
// // The format is AA|op CC|BB.
// registerA = opcodeHighOrderByte;
// int secondWord = (int)reader.ushort();
// registerB = secondWord & 0xff;
// //literalC = (secondWord >> 8) & 0xff;
// literalC = (byte)(secondWord >> 8);
// }
/**
* Returns the RegisterA encoded in the given 16-bit opcode.
* @return the RegisterA.
*/
public static int getRegisterA(int opcode) {
return (opcode >> 8) & 0xff;
}
/**
* Returns the RegisterB and LiteralC encoded as an int, from where the Reader points.
* <i>It must be performed only once after having read the opcode.</i>. To decode the returned
* int, use getRegisterBFromEncodedRegisterBAndLiteralC and getLiteralCFromEncodedRegisterBAndLiteralC.
* @param reader reader pointing after the 16-bit opcode.
* @return the RegisterB and LiteralC, encoded as one single int.
*/
public static int getEncodedRegisterBAndLiteralC(IDalvikValueReader reader) {
return reader.ushort();
}
/**
* Returns the RegisterB encoded inside the given value, that should contained both RegisterB and LiteralC
* from the getEncodedRegisterBAndLiteralC method.
* @param encodedRegisterBAndLiteralC the RegisterB and C encoded as an int.
* @return the RegisterB.
*/
public static int getRegisterBFromEncodedRegisterBAndC(int encodedRegisterBAndLiteralC) {
return encodedRegisterBAndLiteralC & 0xff;
}
/**
* Returns the LiteralC encoded inside the given value, that should contained both RegisterB and LiteralC
* from the getEncodedRegisterBAndLiteralC method.
* @param encodedRegisterBAndC the RegisterB and LiteralC encoded as an int.
* @return the LiteralC.
*/
public static int getLiteralCFromEncodedRegisterBAndLiteralC(int encodedRegisterBAndC) {
return (byte)(encodedRegisterBAndC >> 8);
}
/**
* Skips the data of this Instruction.
* @param reader reader on the Instruction to parse, pointing after the 16-bit opcode.
*/
public static void skip(IDalvikValueReader reader) {
reader.relativeSeek(INSTRUCTION_SIZE - 2); // The first word has already been read.
}
/**
* Constructor of the Instruction by providing all the elements it's composed of.
* @param opcode 8 or 16 bits opcode.
* @param registerA the first register to store.
* @param registerB the second register to store.
* @param value the literal to store.
*/
public InstructionFormat22B(int opcode, int registerA, int registerB, int value) {
super(opcode);
this.registerA = registerA;
this.registerB = registerB;
this.literalC = value;
}
@Override
public int getSize() {
return INSTRUCTION_SIZE;
}
// @Override
// public int[] getUsedRegisters() {
// return new int[] { registerA, registerB };
// }
// @Override
// public int getNbEncodedRegisters() {
// return 2;
// }
@Override
public void write(ByteVector out, ConstantPool constantPool) {
test8BitsLimit(registerA | registerB);
out.putShort(((registerA & 0xff) << 8) + opcodeByte);
out.putShort(((literalC & 0xff) << 8) + (registerB & 0xff));
}
}