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.SimpleInsn; 22import com.android.dx.rop.code.RegisterSpec; 23import com.android.dx.rop.code.RegisterSpecList; 24import com.android.dx.util.AnnotatedOutput; 25 26import java.util.BitSet; 27 28/** 29 * Instruction format {@code 12x}. See the instruction format spec 30 * for details. 31 */ 32public final class Form12x extends InsnFormat { 33 /** {@code non-null;} unique instance of this class */ 34 public static final InsnFormat THE_ONE = new Form12x(); 35 36 /** 37 * Constructs an instance. This class is not publicly 38 * instantiable. Use {@link #THE_ONE}. 39 */ 40 private Form12x() { 41 // This space intentionally left blank. 42 } 43 44 /** {@inheritDoc} */ 45 @Override 46 public String insnArgString(DalvInsn insn) { 47 RegisterSpecList regs = insn.getRegisters(); 48 int sz = regs.size(); 49 50 /* 51 * The (sz - 2) and (sz - 1) below makes this code work for 52 * both the two- and three-register ops. (See "case 3" in 53 * isCompatible(), below.) 54 */ 55 56 return regs.get(sz - 2).regString() + ", " + 57 regs.get(sz - 1).regString(); 58 } 59 60 /** {@inheritDoc} */ 61 @Override 62 public String insnCommentString(DalvInsn insn, boolean noteIndices) { 63 // This format has no comment. 64 return ""; 65 } 66 67 /** {@inheritDoc} */ 68 @Override 69 public int codeSize() { 70 return 1; 71 } 72 73 /** {@inheritDoc} */ 74 @Override 75 public boolean isCompatible(DalvInsn insn) { 76 if (!(insn instanceof SimpleInsn)) { 77 return false; 78 } 79 80 RegisterSpecList regs = insn.getRegisters(); 81 RegisterSpec rs1; 82 RegisterSpec rs2; 83 84 switch (regs.size()) { 85 case 2: { 86 rs1 = regs.get(0); 87 rs2 = regs.get(1); 88 break; 89 } 90 case 3: { 91 /* 92 * This format is allowed for ops that are effectively 93 * 3-arg but where the first two args are identical. 94 */ 95 rs1 = regs.get(1); 96 rs2 = regs.get(2); 97 if (rs1.getReg() != regs.get(0).getReg()) { 98 return false; 99 } 100 break; 101 } 102 default: { 103 return false; 104 } 105 } 106 107 return unsignedFitsInNibble(rs1.getReg()) && 108 unsignedFitsInNibble(rs2.getReg()); 109 } 110 111 /** {@inheritDoc} */ 112 @Override 113 public BitSet compatibleRegs(DalvInsn insn) { 114 RegisterSpecList regs = insn.getRegisters(); 115 BitSet bits = new BitSet(2); 116 117 bits.set(0, unsignedFitsInNibble(regs.get(0).getReg())); 118 bits.set(1, unsignedFitsInNibble(regs.get(1).getReg())); 119 return bits; 120 } 121 122 /** {@inheritDoc} */ 123 @Override 124 public void writeTo(AnnotatedOutput out, DalvInsn insn) { 125 RegisterSpecList regs = insn.getRegisters(); 126 int sz = regs.size(); 127 128 /* 129 * The (sz - 2) and (sz - 1) below makes this code work for 130 * both the two- and three-register ops. (See "case 3" in 131 * isCompatible(), above.) 132 */ 133 134 write(out, opcodeUnit(insn, 135 makeByte(regs.get(sz - 2).getReg(), 136 regs.get(sz - 1).getReg()))); 137 } 138} 139