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;
24
25import java.util.BitSet;
26
27/**
28 * Instruction format {@code 22t}. See the instruction format spec
29 * for details.
30 */
31public final class Form22t extends InsnFormat {
32    /** {@code non-null;} unique instance of this class */
33    public static final InsnFormat THE_ONE = new Form22t();
34
35    /**
36     * Constructs an instance. This class is not publicly
37     * instantiable. Use {@link #THE_ONE}.
38     */
39    private Form22t() {
40        // This space intentionally left blank.
41    }
42
43    /** {@inheritDoc} */
44    @Override
45    public String insnArgString(DalvInsn insn) {
46        RegisterSpecList regs = insn.getRegisters();
47        return regs.get(0).regString() + ", " + regs.get(1).regString() +
48            ", " + branchString(insn);
49    }
50
51    /** {@inheritDoc} */
52    @Override
53    public String insnCommentString(DalvInsn insn, boolean noteIndices) {
54        return branchComment(insn);
55    }
56
57    /** {@inheritDoc} */
58    @Override
59    public int codeSize() {
60        return 2;
61    }
62
63    /** {@inheritDoc} */
64    @Override
65    public boolean isCompatible(DalvInsn insn) {
66        RegisterSpecList regs = insn.getRegisters();
67
68        if (!((insn instanceof TargetInsn) &&
69              (regs.size() == 2) &&
70              unsignedFitsInNibble(regs.get(0).getReg()) &&
71              unsignedFitsInNibble(regs.get(1).getReg()))) {
72            return false;
73        }
74
75        TargetInsn ti = (TargetInsn) insn;
76        return ti.hasTargetOffset() ? branchFits(ti) : true;
77    }
78
79    /** {@inheritDoc} */
80    @Override
81    public BitSet compatibleRegs(DalvInsn insn) {
82        RegisterSpecList regs = insn.getRegisters();
83        BitSet bits = new BitSet(2);
84
85        bits.set(0, unsignedFitsInNibble(regs.get(0).getReg()));
86        bits.set(1, unsignedFitsInNibble(regs.get(1).getReg()));
87        return bits;
88    }
89
90    /** {@inheritDoc} */
91    @Override
92    public boolean branchFits(TargetInsn insn) {
93        int offset = insn.getTargetOffset();
94
95        // Note: A zero offset would fit, but it is prohibited by the spec.
96        return (offset != 0) && signedFitsInShort(offset);
97    }
98
99    /** {@inheritDoc} */
100    @Override
101    public void writeTo(AnnotatedOutput out, DalvInsn insn) {
102        RegisterSpecList regs = insn.getRegisters();
103        int offset = ((TargetInsn) insn).getTargetOffset();
104
105        write(out,
106              opcodeUnit(insn,
107                         makeByte(regs.get(0).getReg(), regs.get(1).getReg())),
108              (short) offset);
109    }
110}
111