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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.CstLiteralBits;
     25 import com.android.dexgen.util.AnnotatedOutput;
     26 
     27 /**
     28  * Instruction format {@code 21s}. See the instruction format spec
     29  * for details.
     30  */
     31 public final class Form21s extends InsnFormat {
     32     /** {@code non-null;} unique instance of this class */
     33     public static final InsnFormat THE_ONE = new Form21s();
     34 
     35     /**
     36      * Constructs an instance. This class is not publicly
     37      * instantiable. Use {@link #THE_ONE}.
     38      */
     39     private Form21s() {
     40         // This space intentionally left blank.
     41     }
     42 
     43     /** {@inheritDoc} */
     44     @Override
     45     public String insnArgString(DalvInsn insn) {
     46         RegisterSpecList regs = insn.getRegisters();
     47         CstLiteralBits value = (CstLiteralBits) ((CstInsn) insn).getConstant();
     48 
     49         return regs.get(0).regString() + ", " + literalBitsString(value);
     50     }
     51 
     52     /** {@inheritDoc} */
     53     @Override
     54     public String insnCommentString(DalvInsn insn, boolean noteIndices) {
     55         CstLiteralBits value = (CstLiteralBits) ((CstInsn) insn).getConstant();
     56         return literalBitsComment(value, 16);
     57     }
     58 
     59     /** {@inheritDoc} */
     60     @Override
     61     public int codeSize() {
     62         return 2;
     63     }
     64 
     65     /** {@inheritDoc} */
     66     @Override
     67     public boolean isCompatible(DalvInsn insn) {
     68         RegisterSpecList regs = insn.getRegisters();
     69         if (!((insn instanceof CstInsn) &&
     70               (regs.size() == 1) &&
     71               unsignedFitsInByte(regs.get(0).getReg()))) {
     72             return false;
     73         }
     74 
     75         CstInsn ci = (CstInsn) insn;
     76         Constant cst = ci.getConstant();
     77 
     78         if (!(cst instanceof CstLiteralBits)) {
     79             return false;
     80         }
     81 
     82         CstLiteralBits cb = (CstLiteralBits) cst;
     83 
     84         return cb.fitsInInt() && signedFitsInShort(cb.getIntBits());
     85     }
     86 
     87     /** {@inheritDoc} */
     88     @Override
     89     public InsnFormat nextUp() {
     90         return Form21h.THE_ONE;
     91     }
     92 
     93     /** {@inheritDoc} */
     94     @Override
     95     public void writeTo(AnnotatedOutput out, DalvInsn insn) {
     96         RegisterSpecList regs = insn.getRegisters();
     97         int value =
     98             ((CstLiteralBits) ((CstInsn) insn).getConstant()).getIntBits();
     99 
    100         write(out,
    101               opcodeUnit(insn, regs.get(0).getReg()),
    102               (short) value);
    103     }
    104 }
    105