public static string Disassemble(byte[] program, int length)
{
StringBuilder builder = new StringBuilder();
var position = 0;
while (position < length)
{
var opcode = (Opcode)program[position];
if (opcode == Opcode.Metadata)
{
var m1 = program[position + 1];
var m2 = program[position + 2];
var m3 = program[position + 3];
builder.AppendFormat("\nFunction\n{0:D3}:\tMethod [Params: {3}]", position, m1, m2, m3);
position += 4;
}
else
{
builder.AppendFormat("{0:D3}:\t{1, -16}", position, opcode);
position++;
foreach (Type t in OpcodeDefinition.For(opcode).Params)
{
if (t == typeof(byte))
{
builder.AppendFormat("{0:X2} ({0})\t", program[position++]);
}
else if (t == typeof(short))
{
builder.AppendFormat("{0:X4} ({0})\t", BitConverter.ToInt16(program, position));
position += sizeof(short);
}
else if (t == typeof(int))
{
builder.AppendFormat("{0:X8} ({0})\t", BitConverter.ToInt32(program, position));
position += sizeof(int);
}
else if (t == typeof(long))
{
builder.AppendFormat("{0:X16} ({0})\t", BitConverter.ToInt64(program, position));
position += sizeof(int);
}
else
{
throw new NotImplementedException();
}
}
}
builder.AppendLine();
}
return(builder.ToString());
}
public void Emit(Opcode opcode, long param1)
{
Requires.That(OpcodeDefinition.For(opcode).Params.SequenceEqual(new Type[] { typeof(int) }));
Buffer.Position = Length;
writer.Write((byte)opcode);
writer.Write(param1);
writer.Flush();
Length = (int)Buffer.Position;
}
public byte[] Link(IEnumerable <FunctionBuilder> emitters)
{
// goes through all the emitters, lays them out in memory and then links them to their
// actual memory addresses.
// first emitter is interpreted as main.
var totalLength = emitters.Sum(e => e.Length);
var memoryStream = new MemoryStream(totalLength);
var addresses = new Dictionary <string, int>();
// layout all emitters
var offset = OpcodeDefinition.Stride(Opcode.Jump16) + OpcodeDefinition.Stride(Opcode.Halt);
var entry = emitters.First();
foreach (var emitter in emitters)
{
var disassembly = Disassembler.Disassemble(emitter.Buffer.GetBuffer(), emitter.Length);
//Console.WriteLine(disassembly);
Console.WriteLine($"Linked {emitter.Name} @ {offset}");
addresses.Add(emitter.Name, offset);
emitter.Address = offset;
offset += emitter.Length;
}
// set absolute addresses
foreach (var emitter in emitters)
{
foreach (var call in emitter.Calls)
{
emitter.Link(call.Key, addresses[call.Value]);
}
}
// Write jump to entry function.
memoryStream.WriteByte((byte)Opcode.Call16);
memoryStream.Write(BitConverter.GetBytes((short)addresses[entry.Name]), 0, sizeof(short));
memoryStream.WriteByte((byte)Opcode.Halt);
// iterate through all emitters, and rewrite
foreach (var emitter in emitters)
{
var disassembly = Disassembler.Disassemble(emitter.Buffer.GetBuffer(), emitter.Length);
//Console.WriteLine(disassembly);
Requires.That(addresses[emitter.Name] == memoryStream.Position);
emitter.Buffer.Position = 0;
emitter.Buffer.CopyTo(memoryStream, emitter.Length);
}
memoryStream.Position = 0;
BinaryReader reader = new BinaryReader(memoryStream);
return(reader.ReadBytes((int)memoryStream.Length));
}
