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      1 /* Copyright (C) 2003 Vladimir Roubtsov. All rights reserved.
      2  *
      3  * This program and the accompanying materials are made available under
      4  * the terms of the Common Public License v1.0 which accompanies this distribution,
      5  * and is available at http://www.eclipse.org/legal/cpl-v10.html
      6  *
      7  * $Id: CodeGen.java,v 1.1.1.1 2004/05/09 16:57:49 vlad_r Exp $
      8  */
      9 package com.vladium.jcd.compiler;
     10 
     11 import com.vladium.jcd.cls.ClassDef;
     12 import com.vladium.jcd.cls.constant.CONSTANT_Integer_info;
     13 import com.vladium.jcd.opcodes.IOpcodes;
     14 import com.vladium.util.ByteArrayOStream;
     15 
     16 // ----------------------------------------------------------------------------
     17 /**
     18  * @author Vlad Roubtsov, (C) 2003
     19  */
     20 public
     21 abstract class CodeGen implements IOpcodes
     22 {
     23     // public: ................................................................
     24 
     25 
     26     public static void load_local_object_var (final ByteArrayOStream out, final int index)
     27     {
     28         if (index <= 3)
     29         {
     30             out.write (_aload_0 + index); // aload_n
     31         }
     32         else if (index <= 0xFF)
     33         {
     34             out.write2 (_aload,
     35                         index);  // indexbyte
     36         }
     37         else
     38         {
     39             out.write4 (_wide,
     40                         _aload,
     41                         index >>> 8,    // indexbyte1
     42                         index);         // indexbyte2
     43         }
     44     }
     45 
     46     public static void store_local_object_var (final ByteArrayOStream out, final int index)
     47     {
     48         if (index <= 3)
     49         {
     50             out.write (_astore_0 + index); // astore_n
     51         }
     52         else if (index <= 0xFF)
     53         {
     54             out.write2 (_astore,
     55                         index);  // indexbyte
     56         }
     57         else
     58         {
     59             out.write4 (_wide,
     60                         _astore,
     61                         index >>> 8,    // indexbyte1
     62                         index);         // indexbyte2
     63         }
     64 
     65         // [stack -1]
     66     }
     67 
     68     public static void push_int_value (final ByteArrayOStream out, final ClassDef cls, final int value)
     69     {
     70         if ((-1 <= value) && (value <= 5))
     71         {
     72             out.write (_iconst_0 + value);
     73         }
     74         else if ((-128 <= value) && (value <= 127))
     75         {
     76             out.write2 (_bipush,
     77                         value); // byte1
     78         }
     79         else if ((-32768 <= value) && (value <= 32767))
     80         {
     81             out.write3 (_sipush,
     82                         value >>> 8,    // byte1
     83                         value);         // byte2
     84         }
     85         else // we have to create an Integer constant in the constant pool:
     86         {
     87             // TODO: check if it's already there
     88             final int index = cls.getConstants ().add (new CONSTANT_Integer_info (value));
     89 
     90             if (index <= 0xFF)
     91             {
     92                 out.write2 (_ldc,
     93                             index);  // index
     94             }
     95             else // must use ldc_w
     96             {
     97                 out.write3 (_ldc_w,
     98                             index >>> 8,  // indexbyte1
     99                             index);       // indexbyte2
    100             }
    101         }
    102 
    103         // [stack +1]
    104     }
    105 
    106     public static void push_constant_index (final ByteArrayOStream out, final int index)
    107     {
    108         if (index <= 0xFF)
    109         {
    110             out.write2 (_ldc,
    111                        index);  // indexbyte
    112         }
    113         else
    114         {
    115             out.write3 (_ldc_w,
    116                         index >>> 8,     // indexbyte1
    117                         index);          // indexbyte2
    118         }
    119 
    120         // [stack +1]
    121     }
    122 
    123     // protected: .............................................................
    124 
    125     // package: ...............................................................
    126 
    127     // private: ...............................................................
    128 
    129 
    130     private CodeGen () {} // prevent subclassing
    131 
    132 } // end of class
    133 // ----------------------------------------------------------------------------
    134