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.dexgen.dex.code.form; 18 19import com.android.dexgen.dex.code.DalvInsn; 20import com.android.dexgen.dex.code.HighRegisterPrefix; 21import com.android.dexgen.dex.code.InsnFormat; 22import com.android.dexgen.dex.code.SimpleInsn; 23import com.android.dexgen.rop.code.RegisterSpec; 24import com.android.dexgen.rop.code.RegisterSpecList; 25import com.android.dexgen.util.AnnotatedOutput; 26 27/** 28 * Instruction format {@code 12x}. See the instruction format spec 29 * for details. 30 */ 31public final class Form12x extends InsnFormat { 32 /** {@code non-null;} unique instance of this class */ 33 public static final InsnFormat THE_ONE = new Form12x(); 34 35 /** 36 * Constructs an instance. This class is not publicly 37 * instantiable. Use {@link #THE_ONE}. 38 */ 39 private Form12x() { 40 // This space intentionally left blank. 41 } 42 43 /** {@inheritDoc} */ 44 @Override 45 public String insnArgString(DalvInsn insn) { 46 RegisterSpecList regs = insn.getRegisters(); 47 int sz = regs.size(); 48 49 /* 50 * The (sz - 2) and (sz - 1) below makes this code work for 51 * both the two- and three-register ops. (See "case 3" in 52 * isCompatible(), below.) 53 */ 54 55 return regs.get(sz - 2).regString() + ", " + 56 regs.get(sz - 1).regString(); 57 } 58 59 /** {@inheritDoc} */ 60 @Override 61 public String insnCommentString(DalvInsn insn, boolean noteIndices) { 62 // This format has no comment. 63 return ""; 64 } 65 66 /** {@inheritDoc} */ 67 @Override 68 public int codeSize() { 69 return 1; 70 } 71 72 /** {@inheritDoc} */ 73 @Override 74 public boolean isCompatible(DalvInsn insn) { 75 if (!(insn instanceof SimpleInsn)) { 76 return false; 77 } 78 79 RegisterSpecList regs = insn.getRegisters(); 80 RegisterSpec rs1; 81 RegisterSpec rs2; 82 83 switch (regs.size()) { 84 case 2: { 85 rs1 = regs.get(0); 86 rs2 = regs.get(1); 87 break; 88 } 89 case 3: { 90 /* 91 * This format is allowed for ops that are effectively 92 * 3-arg but where the first two args are identical. 93 */ 94 rs1 = regs.get(1); 95 rs2 = regs.get(2); 96 if (rs1.getReg() != regs.get(0).getReg()) { 97 return false; 98 } 99 break; 100 } 101 default: { 102 return false; 103 } 104 } 105 106 return unsignedFitsInNibble(rs1.getReg()) && 107 unsignedFitsInNibble(rs2.getReg()); 108 } 109 110 /** {@inheritDoc} */ 111 @Override 112 public InsnFormat nextUp() { 113 return Form22x.THE_ONE; 114 } 115 116 /** {@inheritDoc} */ 117 @Override 118 public void writeTo(AnnotatedOutput out, DalvInsn insn) { 119 RegisterSpecList regs = insn.getRegisters(); 120 int sz = regs.size(); 121 122 /* 123 * The (sz - 2) and (sz - 1) below makes this code work for 124 * both the two- and three-register ops. (See "case 3" in 125 * isCompatible(), above.) 126 */ 127 128 write(out, opcodeUnit(insn, 129 makeByte(regs.get(sz - 2).getReg(), 130 regs.get(sz - 1).getReg()))); 131 } 132} 133