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      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 
     17 package com.android.dexgen.dex.code.form;
     18 
     19 import com.android.dexgen.dex.code.CstInsn;
     20 import com.android.dexgen.dex.code.DalvInsn;
     21 import com.android.dexgen.dex.code.InsnFormat;
     22 import com.android.dexgen.rop.code.RegisterSpecList;
     23 import com.android.dexgen.rop.cst.Constant;
     24 import com.android.dexgen.rop.cst.CstFieldRef;
     25 import com.android.dexgen.rop.cst.CstString;
     26 import com.android.dexgen.rop.cst.CstType;
     27 import com.android.dexgen.util.AnnotatedOutput;
     28 
     29 /**
     30  * Instruction format {@code 22c}. See the instruction format spec
     31  * for details.
     32  */
     33 public final class Form22c extends InsnFormat {
     34     /** {@code non-null;} unique instance of this class */
     35     public static final InsnFormat THE_ONE = new Form22c();
     36 
     37     /**
     38      * Constructs an instance. This class is not publicly
     39      * instantiable. Use {@link #THE_ONE}.
     40      */
     41     private Form22c() {
     42         // This space intentionally left blank.
     43     }
     44 
     45     /** {@inheritDoc} */
     46     @Override
     47     public String insnArgString(DalvInsn insn) {
     48         RegisterSpecList regs = insn.getRegisters();
     49         return regs.get(0).regString() + ", " + regs.get(1).regString() +
     50             ", " + cstString(insn);
     51     }
     52 
     53     /** {@inheritDoc} */
     54     @Override
     55     public String insnCommentString(DalvInsn insn, boolean noteIndices) {
     56         if (noteIndices) {
     57             return cstComment(insn);
     58         } else {
     59             return "";
     60         }
     61     }
     62 
     63     /** {@inheritDoc} */
     64     @Override
     65     public int codeSize() {
     66         return 2;
     67     }
     68 
     69     /** {@inheritDoc} */
     70     @Override
     71     public boolean isCompatible(DalvInsn insn) {
     72         RegisterSpecList regs = insn.getRegisters();
     73         if (!((insn instanceof CstInsn) &&
     74               (regs.size() == 2) &&
     75               unsignedFitsInNibble(regs.get(0).getReg()) &&
     76               unsignedFitsInNibble(regs.get(1).getReg()))) {
     77             return false;
     78         }
     79 
     80         CstInsn ci = (CstInsn) insn;
     81         int cpi = ci.getIndex();
     82 
     83         if (! unsignedFitsInShort(cpi)) {
     84             return false;
     85         }
     86 
     87         Constant cst = ci.getConstant();
     88         return (cst instanceof CstType) ||
     89             (cst instanceof CstFieldRef);
     90     }
     91 
     92     /** {@inheritDoc} */
     93     @Override
     94     public InsnFormat nextUp() {
     95         return null;
     96     }
     97 
     98     /** {@inheritDoc} */
     99     @Override
    100     public void writeTo(AnnotatedOutput out, DalvInsn insn) {
    101         RegisterSpecList regs = insn.getRegisters();
    102         int cpi = ((CstInsn) insn).getIndex();
    103 
    104         write(out,
    105               opcodeUnit(insn,
    106                          makeByte(regs.get(0).getReg(), regs.get(1).getReg())),
    107               (short) cpi);
    108     }
    109 }
    110