Form11n.java revision 579d7739c53a2707ad711a2d2cae46d7d782f061 
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.CstInsn;
20import com.android.dx.dex.code.DalvInsn;
21import com.android.dx.dex.code.InsnFormat;
22import com.android.dx.rop.code.RegisterSpecList;
23import com.android.dx.rop.cst.Constant;
24import com.android.dx.rop.cst.CstLiteralBits;
25import com.android.dx.util.AnnotatedOutput;
26
27import java.util.BitSet;
28
29/**
30 * Instruction format {@code 11n}. See the instruction format spec
31 * for details.
32 */
33public final class Form11n extends InsnFormat {
34    /** {@code non-null;} unique instance of this class */
35    public static final InsnFormat THE_ONE = new Form11n();
36
37    /**
38     * Constructs an instance. This class is not publicly
39     * instantiable. Use {@link #THE_ONE}.
40     */
41    private Form11n() {
42        // This space intentionally left blank.
43    }
44
45    /** {@inheritDoc} */
46    @Override
47    public String insnArgString(DalvInsn insn) {
48        RegisterSpecList regs = insn.getRegisters();
49        CstLiteralBits value = (CstLiteralBits) ((CstInsn) insn).getConstant();
50
51        return regs.get(0).regString() + ", " + literalBitsString(value);
52    }
53
54    /** {@inheritDoc} */
55    @Override
56    public String insnCommentString(DalvInsn insn, boolean noteIndices) {
57        CstLiteralBits value = (CstLiteralBits) ((CstInsn) insn).getConstant();
58        return literalBitsComment(value, 4);
59    }
60
61    /** {@inheritDoc} */
62    @Override
63    public int codeSize() {
64        return 1;
65    }
66
67    /** {@inheritDoc} */
68    @Override
69    public boolean isCompatible(DalvInsn insn) {
70        RegisterSpecList regs = insn.getRegisters();
71
72        if (!((insn instanceof CstInsn) &&
73              (regs.size() == 1) &&
74              unsignedFitsInNibble(regs.get(0).getReg()))) {
75            return false;
76        }
77
78        CstInsn ci = (CstInsn) insn;
79        Constant cst = ci.getConstant();
80
81        if (!(cst instanceof CstLiteralBits)) {
82            return false;
83        }
84
85        CstLiteralBits cb = (CstLiteralBits) cst;
86
87        return cb.fitsInInt() && signedFitsInNibble(cb.getIntBits());
88    }
89
90    /** {@inheritDoc} */
91    @Override
92    public BitSet compatibleRegs(DalvInsn insn) {
93        RegisterSpecList regs = insn.getRegisters();
94        BitSet bits = new BitSet(1);
95
96        bits.set(0, unsignedFitsInNibble(regs.get(0).getReg()));
97        return bits;
98    }
99
100    /** {@inheritDoc} */
101    @Override
102    public void writeTo(AnnotatedOutput out, DalvInsn insn) {
103        RegisterSpecList regs = insn.getRegisters();
104        int value =
105            ((CstLiteralBits) ((CstInsn) insn).getConstant()).getIntBits();
106
107        write(out,
108              opcodeUnit(insn, makeByte(regs.get(0).getReg(), value & 0xf)));
109    }
110}
111