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.TargetInsn;
22import com.android.dx.rop.code.RegisterSpecList;
23import com.android.dx.util.AnnotatedOutput;
24import java.util.BitSet;
25
26/**
27 * Instruction format {@code 22t}. See the instruction format spec
28 * for details.
29 */
30public final class Form22t extends InsnFormat {
31    /** {@code non-null;} unique instance of this class */
32    public static final InsnFormat THE_ONE = new Form22t();
33
34    /**
35     * Constructs an instance. This class is not publicly
36     * instantiable. Use {@link #THE_ONE}.
37     */
38    private Form22t() {
39        // This space intentionally left blank.
40    }
41
42    /** {@inheritDoc} */
43    @Override
44    public String insnArgString(DalvInsn insn) {
45        RegisterSpecList regs = insn.getRegisters();
46        return regs.get(0).regString() + ", " + regs.get(1).regString() +
47            ", " + branchString(insn);
48    }
49
50    /** {@inheritDoc} */
51    @Override
52    public String insnCommentString(DalvInsn insn, boolean noteIndices) {
53        return branchComment(insn);
54    }
55
56    /** {@inheritDoc} */
57    @Override
58    public int codeSize() {
59        return 2;
60    }
61
62    /** {@inheritDoc} */
63    @Override
64    public boolean isCompatible(DalvInsn insn) {
65        RegisterSpecList regs = insn.getRegisters();
66
67        if (!((insn instanceof TargetInsn) &&
68              (regs.size() == 2) &&
69              unsignedFitsInNibble(regs.get(0).getReg()) &&
70              unsignedFitsInNibble(regs.get(1).getReg()))) {
71            return false;
72        }
73
74        TargetInsn ti = (TargetInsn) insn;
75        return ti.hasTargetOffset() ? branchFits(ti) : true;
76    }
77
78    /** {@inheritDoc} */
79    @Override
80    public BitSet compatibleRegs(DalvInsn insn) {
81        RegisterSpecList regs = insn.getRegisters();
82        BitSet bits = new BitSet(2);
83
84        bits.set(0, unsignedFitsInNibble(regs.get(0).getReg()));
85        bits.set(1, unsignedFitsInNibble(regs.get(1).getReg()));
86        return bits;
87    }
88
89    /** {@inheritDoc} */
90    @Override
91    public boolean branchFits(TargetInsn insn) {
92        int offset = insn.getTargetOffset();
93
94        // Note: A zero offset would fit, but it is prohibited by the spec.
95        return (offset != 0) && signedFitsInShort(offset);
96    }
97
98    /** {@inheritDoc} */
99    @Override
100    public void writeTo(AnnotatedOutput out, DalvInsn insn) {
101        RegisterSpecList regs = insn.getRegisters();
102        int offset = ((TargetInsn) insn).getTargetOffset();
103
104        write(out,
105              opcodeUnit(insn,
106                         makeByte(regs.get(0).getReg(), regs.get(1).getReg())),
107              (short) offset);
108    }
109}
110