org/jpc/output/OutputFrame.java

   1 /*
   2     JPC-RR: A x86 PC Hardware Emulator
   3     Release 1
   4
   5     Copyright (C) 2007-2009 Isis Innovation Limited
   6     Copyright (C) 2009-2010 H. Ilari Liusvaara
   7
   8     This program is free software; you can redistribute it and/or modify
   9     it under the terms of the GNU General Public License version 2 as published by
  10     the Free Software Foundation.
  11
  12     This program is distributed in the hope that it will be useful,
  13     but WITHOUT ANY WARRANTY; without even the implied warranty of
  14     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15     GNU General Public License for more details.
  16
  17     You should have received a copy of the GNU General Public License along
  18     with this program; if not, write to the Free Software Foundation, Inc.,
  19     51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  20
  21     Based on JPC x86 PC Hardware emulator,
  22     A project from the Physics Dept, The University of Oxford
  23
  24     Details about original JPC can be found at:
  25
  26     www-jpc.physics.ox.ac.uk
  27
  28 */
  29
  30 package org.jpc.output;
  31
  32 import java.io.*;
  33
  34 public abstract class OutputFrame
  35 {
  36     private long time;
  37     private byte minor;
  38
  39     public OutputFrame(long timeStamp, byte minorType)
  40     {
  41         time = timeStamp;
  42         minor = minorType;
  43     }
  44
  45     protected void adjustTime(long delta)
  46     {
  47         time += delta;
  48     }
  49
  50     public byte[] dump(short channel, long timeBase) throws IOException
  51     {
  52         int len = 8;
  53         int llen = 1;
  54         int skips = 0;
  55         if(channel == -1)
  56             throw new IOException("Channel 0xFFFF is reserved");
  57         long delta = time - timeBase;
  58         if(delta < 0)
  59             throw new IOException("Event times must be monotonic");
  60
  61         byte[] internal = dumpInternal();
  62
  63         //Calculate length of frame and allocate it.
  64         while(delta >= 0xFFFFFFFFL) {
  65             skips++;
  66             len += 6;
  67             delta -= 0xFFFFFFFFL;
  68         }
  69         int ilen = (internal != null) ? internal.length : 0;
  70         while(ilen > 127) {
  71             len++;
  72             llen++;
  73             ilen >>>= 7;
  74         }
  75         len += ((internal != null) ? internal.length : 0);
  76         byte[] frame = new byte[len];
  77
  78         //Write the frame.
  79         int offset = 6 * skips;
  80         for(int i = 0; i < offset; i++)
  81             frame[i] = (byte)255;
  82         frame[offset + 0] = (byte)((channel >>> 8) & 0xFF);
  83         frame[offset + 1] = (byte)(channel & 0xFF);
  84         frame[offset + 2] = (byte)((delta >>> 24) & 0xFF);
  85         frame[offset + 3] = (byte)((delta >>> 16) & 0xFF);
  86         frame[offset + 4] = (byte)((delta >>> 8) & 0xFF);
  87         frame[offset + 5] = (byte)(delta & 0xFF);
  88         frame[offset + 6] = minor;
  89         ilen = (internal != null) ? internal.length : 0;
  90         for(int i = llen; i > 0; i--) {
  91             frame[offset + 6 + i] = (byte)(((i == llen) ? 0x00 : 0x80) | (ilen & 0x7F));
  92             ilen >>>= 7;
  93         }
  94         if(internal != null)
  95             System.arraycopy(internal, 0, frame, offset + 7 + llen, internal.length);
  96         return frame;
  97     }
  98
  99     public long getTime()
 100     {
 101         return time;
 102     }
 103
 104     protected abstract byte[] dumpInternal();
 105 };