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.dexgen.dex.code.form;
18
19import com.android.dexgen.dex.code.CstInsn;
20import com.android.dexgen.dex.code.DalvInsn;
21import com.android.dexgen.dex.code.InsnFormat;
22import com.android.dexgen.rop.code.RegisterSpecList;
23import com.android.dexgen.rop.cst.Constant;
24import com.android.dexgen.rop.cst.CstLiteralBits;
25import com.android.dexgen.util.AnnotatedOutput;
26
27/**
28 * Instruction format {@code 11n}. See the instruction format spec
29 * for details.
30 */
31public final class Form11n extends InsnFormat {
32    /** {@code non-null;} unique instance of this class */
33    public static final InsnFormat THE_ONE = new Form11n();
34
35    /**
36     * Constructs an instance. This class is not publicly
37     * instantiable. Use {@link #THE_ONE}.
38     */
39    private Form11n() {
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, 4);
57    }
58
59    /** {@inheritDoc} */
60    @Override
61    public int codeSize() {
62        return 1;
63    }
64
65    /** {@inheritDoc} */
66    @Override
67    public boolean isCompatible(DalvInsn insn) {
68        RegisterSpecList regs = insn.getRegisters();
69
70        if (!((insn instanceof CstInsn) &&
71              (regs.size() == 1) &&
72              unsignedFitsInNibble(regs.get(0).getReg()))) {
73            return false;
74        }
75
76        CstInsn ci = (CstInsn) insn;
77        Constant cst = ci.getConstant();
78
79        if (!(cst instanceof CstLiteralBits)) {
80            return false;
81        }
82
83        CstLiteralBits cb = (CstLiteralBits) cst;
84
85        return cb.fitsInInt() && signedFitsInNibble(cb.getIntBits());
86    }
87
88    /** {@inheritDoc} */
89    @Override
90    public InsnFormat nextUp() {
91        return Form21s.THE_ONE;
92    }
93
94    /** {@inheritDoc} */
95    @Override
96    public void writeTo(AnnotatedOutput out, DalvInsn insn) {
97        RegisterSpecList regs = insn.getRegisters();
98        int value =
99            ((CstLiteralBits) ((CstInsn) insn).getConstant()).getIntBits();
100
101        write(out,
102              opcodeUnit(insn, makeByte(regs.get(0).getReg(), value & 0xf)));
103    }
104}
105