1/* 2 * Copyright (C) 2007 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17package com.android.dx.dex.code.form; 18 19import com.android.dx.dex.code.DalvInsn; 20import com.android.dx.dex.code.InsnFormat; 21import com.android.dx.dex.code.TargetInsn; 22import com.android.dx.rop.code.RegisterSpecList; 23import com.android.dx.util.AnnotatedOutput; 24import java.util.BitSet; 25 26/** 27 * Instruction format {@code 21t}. See the instruction format spec 28 * for details. 29 */ 30public final class Form21t extends InsnFormat { 31 /** {@code non-null;} unique instance of this class */ 32 public static final InsnFormat THE_ONE = new Form21t(); 33 34 /** 35 * Constructs an instance. This class is not publicly 36 * instantiable. Use {@link #THE_ONE}. 37 */ 38 private Form21t() { 39 // This space intentionally left blank. 40 } 41 42 /** {@inheritDoc} */ 43 @Override 44 public String insnArgString(DalvInsn insn) { 45 RegisterSpecList regs = insn.getRegisters(); 46 return regs.get(0).regString() + ", " + branchString(insn); 47 } 48 49 /** {@inheritDoc} */ 50 @Override 51 public String insnCommentString(DalvInsn insn, boolean noteIndices) { 52 return branchComment(insn); 53 } 54 55 /** {@inheritDoc} */ 56 @Override 57 public int codeSize() { 58 return 2; 59 } 60 61 /** {@inheritDoc} */ 62 @Override 63 public boolean isCompatible(DalvInsn insn) { 64 RegisterSpecList regs = insn.getRegisters(); 65 66 if (!((insn instanceof TargetInsn) && 67 (regs.size() == 1) && 68 unsignedFitsInByte(regs.get(0).getReg()))) { 69 return false; 70 } 71 72 TargetInsn ti = (TargetInsn) insn; 73 return ti.hasTargetOffset() ? branchFits(ti) : true; 74 } 75 76 /** {@inheritDoc} */ 77 @Override 78 public BitSet compatibleRegs(DalvInsn insn) { 79 RegisterSpecList regs = insn.getRegisters(); 80 BitSet bits = new BitSet(1); 81 82 bits.set(0, unsignedFitsInByte(regs.get(0).getReg())); 83 return bits; 84 } 85 86 /** {@inheritDoc} */ 87 @Override 88 public boolean branchFits(TargetInsn insn) { 89 int offset = insn.getTargetOffset(); 90 91 // Note: A zero offset would fit, but it is prohibited by the spec. 92 return (offset != 0) && signedFitsInShort(offset); 93 } 94 95 /** {@inheritDoc} */ 96 @Override 97 public void writeTo(AnnotatedOutput out, DalvInsn insn) { 98 RegisterSpecList regs = insn.getRegisters(); 99 int offset = ((TargetInsn) insn).getTargetOffset(); 100 101 write(out, 102 opcodeUnit(insn, regs.get(0).getReg()), 103 (short) offset); 104 } 105} 106