VMCommand ReadOpCode(Stream binary, ref int didread)
{
int op = DataReader.Read8(binary, ref didread) & 0xff; // get unsigned
if (op == 0x09) // opcode for CALL
{
return(null);
}
// check if there is a single-byte opcode
foreach (var de in commands)
{
VMCommand cmd = de.Value;
if (cmd.opcode.Length == 1 && cmd.opcode[0] == op)
{
return(cmd);
}
}
// extend search to get two-byte opcodes as well
int op1 = DataReader.Read8(binary, ref didread) & 0xff;
foreach (var de in commands)
{
VMCommand cmd = de.Value;
if (cmd.opcode.Length == 2 && cmd.opcode[0] == op && cmd.opcode[1] == op1)
{
return(cmd);
}
}
throw new Exception("Unrecognized opcode: " + op + "(" + op1 + ")");
}
private void readByteCodeList()
{
StringReader reader = new StringReader(LMSAssembler.Properties.Resources.bytecodelist);
String line;
while ((line = reader.ReadLine()) != null)
{
int idx = line.IndexOf("//");
if (idx >= 0)
{
line = line.Substring(0, idx);
}
line = line.Trim();
if (line.Length > 0)
{
VMCommand c = new VMCommand(line);
commands.Add(c.name, c);
}
}
reader.Close();
// foreach (VMCommand c in commands.Values)
// {
// Console.WriteLine(c);
// }
}
// ---------------------------------- DISASSEMLER ----------------------------------------------
public void Disassemble(Stream binary, TextWriter writer)
{
Dictionary <int, String> vmobjects = new Dictionary <int, String>();
int didread = 0;
// read file header and object definitions
int magic = DataReader.Read32(binary, ref didread);
if (magic != 0x4F47454C)
{
throw new Exception("Missing LEGO header");
}
int imgsize = DataReader.Read32(binary, ref didread);
int version = DataReader.Read16(binary, ref didread);
int numobjects = DataReader.Read16(binary, ref didread);
int globalbytes = DataReader.Read32(binary, ref didread);
writer.WriteLine("Image size: " + imgsize);
writer.WriteLine("Version: " + version);
writer.WriteLine("Objects: " + numobjects);
writer.WriteLine("Globals bytes: " + globalbytes);
for (int i = 0; i < numobjects; i++)
{
int offset = DataReader.Read32(binary, ref didread);
int owner = DataReader.Read16(binary, ref didread);
int triggercount = DataReader.Read16(binary, ref didread);
int localbytes = DataReader.Read32(binary, ref didread);
if (owner == 0)
{
if (triggercount == 0)
{
vmobjects[offset] = "VMTHREAD THREAD" + (i + 1) + " ( " + localbytes + " locals)";
}
else if (triggercount == 1)
{
vmobjects[offset] = "SUBCALL SUB" + (i + 1) + " ( " + localbytes + " locals)";
}
else
{
throw new Exception("Encountered invalid triggercount value");
}
}
else
{
if (localbytes != 0)
{
throw new Exception("Can not have local bytes for object with owner");
}
vmobjects[offset] = "OBJECT " + (i + 1) + " (+trigercount=" + triggercount + ", owner=" + owner + ")";
}
}
// read all objects
while (didread < imgsize)
{
if (!vmobjects.ContainsKey(didread))
{
throw new Exception("No object starts at position " + didread);
}
String o = vmobjects[didread];
vmobjects.Remove(didread);
writer.WriteLine(o);
// decode parameter specifier for SUBCALL
if (o.StartsWith("SUBCALL"))
{
int localpos = 0;
int numpar = DataReader.Read8(binary, ref didread) & 0xff;
for (int i = 0; i < numpar; i++)
{
String prefix = "";
int desc = DataReader.Read8(binary, ref didread) & 0xff;
if ((desc & 0x80) != 0)
{
prefix = "IN";
}
if ((desc & 0x40) != 0)
{
prefix = prefix + "OUT";
}
switch (desc & 0x07)
{
case 0:
writer.WriteLine(format(localpos, 4) + " " + prefix + "_8");
localpos += 1;
break;
case 1:
writer.WriteLine(format(localpos, 4) + " " + prefix + "_16");
localpos += 2;
break;
case 2:
writer.WriteLine(format(localpos, 4) + " " + prefix + "_32");
localpos += 4;
break;
case 3:
writer.WriteLine(format(localpos, 4) + " " + prefix + "_F");
localpos += 4;
break;
case 4:
int len = DataReader.Read8(binary, ref didread) & 0xff;
writer.WriteLine(format(localpos, 4) + " " + prefix + "_S " + len);
localpos += len;
break;
default:
throw new Exception("Can not decode subcall parameter list");
}
}
}
int objectstart = didread;
for (; ;)
{
writer.Write(format(didread - objectstart, 4) + " ");
// decode bytecodes
VMCommand cmd = ReadOpCode(binary, ref didread);
if (cmd == null)
{
int n;
String objid = ReadParameter(binary, ref didread);
if (!int.TryParse(ReadParameter(binary, ref didread), NumberStyles.Integer, CultureInfo.InvariantCulture, out n))
{
throw new Exception("Invalid specifier for number of CALL parameters");
}
// special handling for CALL
writer.Write("CALL SUB" + objid);
for (int i = 0; i < n; i++)
{
writer.Write(" " + ReadParameter(binary, ref didread));
}
writer.WriteLine();
}
else
{ // normal opcodes
writer.Write(cmd.name);
// decode parameters
int numparameters = cmd.parameters.Length;
for (int i = 0; i < numparameters; i++)
{
String p = ReadParameter(binary, ref didread);
writer.Write(" " + p);
// check if this parameter is a counter to extend the parameter list
if (i < cmd.parameters.Length && cmd.parameters[i] == DataType.ParameterCount)
{
int n;
if (int.TryParse(p, NumberStyles.Integer, CultureInfo.InvariantCulture, out n))
{
numparameters += (n - 1);
}
}
}
writer.WriteLine();
if (cmd.name.Equals("OBJECT_END"))
{
break;
}
}
}
}
}