public ByteCodeExecutor(ByteCodePoint[] program, ILiteral[] literals, int maxVariableIndex)
{
if (program == null) throw new ArgumentNullException(nameof(program));
_program = program;
_literals = literals;
_programCounter = 0;
_environment = new ByteCodeEnvironment(0, 0, null);
_registers = new SimpleReference[maxVariableIndex];
for (var registerIndex = 0; registerIndex<_registers.Length; ++registerIndex)
{
_registers[registerIndex] = new SimpleReference();
}
}
/// <summary>
/// Sets a label referencing the next instruction to be written
/// </summary>
public int Label(object label)
{
// Write the label
var labelIp = _program.Count;
_ipsWithLabel[label] = labelIp;
// Update any instructions that reference the label
List <int> existingReferences;
if (_ipsReferencingLabel.TryGetValue(label, out existingReferences))
{
foreach (var refIp in existingReferences)
{
var old = _program[refIp];
_program[refIp] = new ByteCodePoint(old.Op, labelIp - refIp, old.Arg2);
}
existingReferences.Clear();
}
return(labelIp);
}
/// <summary>
/// Takes any call operations found in this program and replaces them with CallAddress operations
/// </summary>
/// <param name="predicateToLabel">Given the predicate for a Call instruction, returns null or the object representing the label for the address to call</param>
public void BindCalls(Func <ILiteral, object> predicateToLabel)
{
if (predicateToLabel == null)
{
throw new ArgumentNullException(nameof(predicateToLabel));
}
for (int address = 0; address < _program.Count; ++address)
{
if (_program[address].Op == Operation.Call)
{
// Ask for the value of this label
var label = predicateToLabel(_literals[_program[address].Literal]);
var argumentCount = _program[address].Arg2;
int labelAddress;
// Try to map it to an existing address
if (label != null && _ipsWithLabel.TryGetValue(label, out labelAddress))
{
_program[address] = new ByteCodePoint(Operation.CallAddress, labelAddress, argumentCount);
}
}
}
}
/// <summary>
/// Dispatches a particular code point
/// </summary>
public void Dispatch(ByteCodePoint codePoint)
{
// Action depends on the opcode
switch (codePoint.Op)
{
case Operation.Nothing:
break;
case Operation.GetStructure:
GetStructure(codePoint.Literal, codePoint.Arg1, codePoint.Arg2);
break;
case Operation.GetVariable:
GetVariable(codePoint.Arg1, codePoint.Arg2);
break;
case Operation.GetValue:
GetValue(codePoint.Arg1, codePoint.Arg2);
break;
case Operation.PutStructure:
PutStructure(codePoint.Literal, codePoint.Arg1, codePoint.Arg2);
break;
case Operation.PutVariable:
PutVariable(codePoint.Arg1, codePoint.Arg2);
break;
case Operation.PutValue:
PutValue(codePoint.Arg1, codePoint.Arg2);
break;
case Operation.SetVariable:
SetVariable(codePoint.Arg1);
break;
case Operation.SetValue:
SetValue(codePoint.Arg1);
break;
case Operation.UnifyVariable:
UnifyVariable(codePoint.Arg1);
break;
case Operation.UnifyValue:
UnifyValue(codePoint.Arg1);
break;
case Operation.Allocate:
Allocate(codePoint.Arg1, codePoint.Arg2);
break;
case Operation.Deallocate:
Deallocate();
break;
case Operation.Proceed:
Proceed();
break;
case Operation.CallAddress:
CallAddress(codePoint.Arg1, codePoint.Arg2);
break;
case Operation.TryMeElse:
TryMeElse(codePoint.Arg1);
break;
case Operation.RetryMeElse:
RetryMeElse(codePoint.Arg1);
break;
case Operation.TrustMe:
TrustMe();
break;
case Operation.Call:
throw new NotImplementedException("External calls not yet supported");
default:
throw new NotImplementedException("Unknown opcode");
}
}
/// <summary>
/// Dispatches a particular code point
/// </summary>
public void Dispatch(ByteCodePoint codePoint)
{
// Action depends on the opcode
switch (codePoint.Op)
{
case Operation.Nothing:
break;
case Operation.GetStructure:
GetStructure(codePoint.Literal, codePoint.Arg1, codePoint.Arg2);
break;
case Operation.GetVariable:
GetVariable(codePoint.Arg1, codePoint.Arg2);
break;
case Operation.GetValue:
GetValue(codePoint.Arg1, codePoint.Arg2);
break;
case Operation.PutStructure:
PutStructure(codePoint.Literal, codePoint.Arg1, codePoint.Arg2);
break;
case Operation.PutVariable:
PutVariable(codePoint.Arg1, codePoint.Arg2);
break;
case Operation.PutValue:
PutValue(codePoint.Arg1, codePoint.Arg2);
break;
case Operation.SetVariable:
SetVariable(codePoint.Arg1);
break;
case Operation.SetValue:
SetValue(codePoint.Arg1);
break;
case Operation.UnifyVariable:
UnifyVariable(codePoint.Arg1);
break;
case Operation.UnifyValue:
UnifyValue(codePoint.Arg1);
break;
case Operation.Allocate:
Allocate(codePoint.Arg1, codePoint.Arg2);
break;
case Operation.Deallocate:
Deallocate();
break;
case Operation.Proceed:
Proceed();
break;
case Operation.CallAddress:
CallAddress(codePoint.Arg1, codePoint.Arg2);
break;
case Operation.TryMeElse:
TryMeElse(codePoint.Arg1);
break;
case Operation.RetryMeElse:
RetryMeElse(codePoint.Arg1);
break;
case Operation.TrustMe:
TrustMe();
break;
case Operation.Call:
throw new NotImplementedException("External calls not yet supported");
default:
throw new NotImplementedException("Unknown opcode");
}
}
