content: /*
   * Copyright (C) 2007 The Android Open Source Project
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *      http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package com.taobao.android.dx.dex.code.form;
  
  import com.taobao.android.dx.dex.code.DalvInsn;
  import com.taobao.android.dx.dex.code.InsnFormat;
  import com.taobao.android.dx.dex.code.SimpleInsn;
  import com.taobao.android.dx.rop.code.RegisterSpec;
  import com.taobao.android.dx.rop.code.RegisterSpecList;
  import com.taobao.android.dx.util.AnnotatedOutput;
  import java.util.BitSet;
  
  /**
   * Instruction format {@code 12x}. See the instruction format spec
   * for details.
   */
  public final class Form12x extends InsnFormat {
      /** {@code non-null;} unique instance of this class */
      public static final InsnFormat THE_ONE = new Form12x();
  
      /**
       * Constructs an instance. This class is not publicly
       * instantiable. Use {@link #THE_ONE}.
       */
      private Form12x() {
          // This space intentionally left blank.
      }
  
      /** {@inheritDoc} */
      @Override
      public String insnArgString(DalvInsn insn) {
          RegisterSpecList regs = insn.getRegisters();
          int sz = regs.size();
  
          /*
           * The (sz - 2) and (sz - 1) below makes this code work for
           * both the two- and three-register ops. (See "case 3" in
           * isCompatible(), below.)
           */
  
          return regs.get(sz - 2).regString() + ", " +
              regs.get(sz - 1).regString();
      }
  
      /** {@inheritDoc} */
      @Override
      public String insnCommentString(DalvInsn insn, boolean noteIndices) {
          // This format has no comment.
          return "";
      }
  
      /** {@inheritDoc} */
      @Override
      public int codeSize() {
          return 1;
      }
  
      /** {@inheritDoc} */
      @Override
      public boolean isCompatible(DalvInsn insn) {
          if (!(insn instanceof SimpleInsn)) {
              return false;
          }
  
          RegisterSpecList regs = insn.getRegisters();
          RegisterSpec rs1;
          RegisterSpec rs2;
  
          switch (regs.size()) {
              case 2: {
                  rs1 = regs.get(0);
                  rs2 = regs.get(1);
                  break;
              }
              case 3: {
                  /*
                   * This format is allowed for ops that are effectively
                   * 3-arg but where the first two args are identical.
                   */
                  rs1 = regs.get(1);
                  rs2 = regs.get(2);
                  if (rs1.getReg() != regs.get(0).getReg()) {
                      return false;
                  }
                  break;
              }
              default: {
                  return false;
              }
          }
  
          return unsignedFitsInNibble(rs1.getReg()) &&
              unsignedFitsInNibble(rs2.getReg());
      }
  
      /** {@inheritDoc} */
      @Override
      public BitSet compatibleRegs(DalvInsn insn) {
          RegisterSpecList regs = insn.getRegisters();
          BitSet bits = new BitSet(2);
          int r0 = regs.get(0).getReg();
          int r1 = regs.get(1).getReg();
  
          switch (regs.size()) {
            case 2: {
              bits.set(0, unsignedFitsInNibble(r0));
              bits.set(1, unsignedFitsInNibble(r1));
              break;
            }
            case 3: {
              if (r0 != r1) {
                  bits.set(0, false);
                  bits.set(1, false);
              } else {
                  boolean dstRegComp = unsignedFitsInNibble(r1);
                  bits.set(0, dstRegComp);
                  bits.set(1, dstRegComp);
              }
  
              bits.set(2, unsignedFitsInNibble(regs.get(2).getReg()));
              break;
            }
            default: {
              throw new AssertionError();
            }
          }
  
          return bits;
      }
  
      /** {@inheritDoc} */
      @Override
      public void writeTo(AnnotatedOutput out, DalvInsn insn) {
          RegisterSpecList regs = insn.getRegisters();
          int sz = regs.size();
  
          /*
           * The (sz - 2) and (sz - 1) below makes this code work for
           * both the two- and three-register ops. (See "case 3" in
           * isCompatible(), above.)
           */
  
          write(out, opcodeUnit(insn,
                                makeByte(regs.get(sz - 2).getReg(),
                                         regs.get(sz - 1).getReg())));
      }
  }
  