/* 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.structureCommon.Label;
import org.ow2.asmdex.structureWriter.ConstantPool;
/**
* Encodes and decodes an instruction built with the Dalvik format 22T.
*
* @author Julien Névo
*/
public class InstructionFormat22T extends Instruction
implements ITwoRegistersInstruction, IOffsetInstruction {
private static final int INSTRUCTION_SIZE = 4; // Instruction size in bytes.
private int registerA;
private int registerB;
private int offset;
/**
* Offset in bytes of the instruction from the beginning of the method.
*/
private int instructionOffset;
@Override
public int getRegisterA() {
return registerA;
}
@Override
public int getRegisterB() {
return registerB;
}
@Override
public int getOffset() {
return offset;
}
/**
* Label to switch to jump.
*/
private Label label;
/**
* Returns the label to which the instruction jumps.
* @return the label to which the instruction jumps.
*/
@Override
public Label getLabel() { return label; }
/**
* 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 InstructionFormat22T(IDalvikValueReader reader, int opcode) {
// super(opcode);
//
// // The format is B|A|op CCCC.
// registerA = opcodeHighOrderByte & 0xf;
// registerB = (opcodeHighOrderByte >> 4) & 0xf;
// int readOffset = reader.sshort() * 2; // * 2 because branch offsets are word based.
// // Offset points to the beginning of the branch, from the start of the Dex file.
// offset = reader.getPos() - 4 + readOffset;
// }
/**
* Returns the RegisterA encoded in the given 16-bit opcode.
* @return the RegisterA.
*/
public static int getRegisterA(int opcode) {
return (opcode >> 8) & 0xf;
}
/**
* Returns the RegisterB encoded in the given 16-bit opcode.
* @return the RegisterB.
*/
public static int getRegisterB(int opcode) {
return (opcode >> 12) & 0xf;
}
/**
* Returns the Offset encoded in the given 16-bit opcode. <i>It must be performed only once after
* having read the opcode.</i>
* @param reader reader on the Instruction to parse, pointing after the 16-bit opcode.
* @param opcode the 16-bit opcode.
* @return the Offset from the beginning of the Dex file.
*/
public static int getOffset(IDalvikValueReader reader, int opcode) {
int readOffset = reader.sshort() * 2; // * 2 because branch offsets are word based.
// Offset points to the beginning of the branch, from the start of the Dex file.
return reader.getPos() - 4 + readOffset;
}
/**
* 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 label Label to which is linked this Instruction.
* @param registerA the first register to store.
* @param registerB the first register to store.
* @param instructionOffset offset of this Instruction from the beginning of its Method.
*/
public InstructionFormat22T(int opcode, Label label, int registerA,
int registerB, int instructionOffset) {
super(opcode);
this.label = label;
this.registerA = registerA;
this.registerB = registerB;
this.instructionOffset = instructionOffset;
Instruction.test4BitsLimit(registerA);
Instruction.test4BitsLimit(registerB);
}
@Override
public int getSize() {
return INSTRUCTION_SIZE;
}
// @Override
// public int[] getUsedRegisters() {
// return new int[] { registerA, registerB };
// }
// @Override
// public int getNbEncodedRegisters() {
// return 2;
// }
@Override
public int getInstructionOffset() {
return instructionOffset;
}
@Override
public void setInstructionOffset(int instructionOffset) {
this.instructionOffset = instructionOffset;
};
@Override
public void write(ByteVector out, ConstantPool constantPool) {
test4BitsLimit(registerA | registerB);
// The format is B|A|op CCCC.
int firstShort = ((registerB & 0xf) << 12) + ((registerA & 0xf) << 8) + opcodeByte;
int secondShort = (label.getOffset() - instructionOffset) / 2; // / 2 because offsets are word-based.
out.putShort(firstShort);
out.putShort(secondShort);
}
}