/* 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;
import org.ow2.asmdex.structureWriter.Field;
/**
* Encodes and decodes an instruction built with the Dalvik format 21C.
*
* This Instruction can refer to a Type, a String, or a Field. String and Type are identified by a String, and
* a difference will be made according to the Opcode when writing the Instruction.
*
* @author Julien Névo
*/
public class InstructionFormat21C extends Instruction
implements IOneRegisterInstruction, IIndexInstruction {
private static final int INSTRUCTION_SIZE = 4; // Instruction size in bytes.
private int registerA;
private int indexB;
/**
* String or Type held by this Instruction, to which the Index refers.
*/
private String stringOrType;
/**
* Field identifying the Index, to which the Index refers.
*/
private Field field;
@Override
public int getRegisterA() {
return registerA;
}
@Override
public int getIndex() {
return indexB;
}
/**
* 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 InstructionFormat21C(IDalvikValueReader reader, int opcode) {
// super(opcode);
//
// // The format is AA|op BBBB.
// registerA = opcodeHighOrderByte;
// indexB = reader.ushort();
// }
/**
* 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 IndexB encoded where the Reader points. <i>It must be performed only once after
* having read the opcode.</i>
* @param reader reader pointing after the 16-bit opcode.
* @return the IndexB.
*/
public static int getIndexB(IDalvikValueReader reader) {
return reader.ushort();
}
/**
* Constructor of the Instruction, if it holds a String or a Type.
* @param opcode 8 or 16 bits opcode.
* @param stringOrType string or Type, according to what this Instruction is holding.
* @param registerA the register this Instruction holds.
*/
public InstructionFormat21C(int opcode, String stringOrType, int registerA) {
super(opcode);
this.registerA = registerA;
this.stringOrType = stringOrType;
}
/**
* Constructor of the Instruction, if it holds a Field.
* @param opcode 8 or 16 bits opcode.
* @param field Field to encode.
* @param registerA the register this Instruction holds.
*/
public InstructionFormat21C(int opcode, Field field, int registerA) {
super(opcode);
this.registerA = registerA;
this.field = field;
}
/**
* 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.
}
@Override
public int getSize() {
return INSTRUCTION_SIZE;
}
// @Override
// public int[] getUsedRegisters() {
// int[] usedRegisters;
// // Pair registers or not ?
// if ((opcodeByte == 0x61) || (opcodeByte == 0x68)) {
// usedRegisters = new int[] { registerA, registerA + 1};
// } else {
// usedRegisters = new int[] { registerA };
// }
//
// return usedRegisters;
// }
// @Override
// public int getNbEncodedRegisters() {
// return 1;
// }
@Override
public void write(ByteVector out, ConstantPool constantPool) {
test8BitsLimit(registerA);
// The format is AA|op BBBB.
out.putShort(((registerA & 0xff) << 8) + opcodeByte);
// The index may be a Type, or a String index.
int index;
if (opcodeByte == 0x1a) {
index = constantPool.getStringIndex(stringOrType);
} else if ((opcodeByte == 0x1c) || (opcodeByte == 0x1f) || (opcodeByte == 0x22)) {
index = constantPool.getTypeIndex(stringOrType);
} else { // 0x60...0x6d
index = constantPool.getFieldIndex(field);
}
out.putShort(index);
}
}