public InstructionPendingEventArgs(Operations.IOperationUnit operationUnit, Word instruction, int programCounter, SerialAbacus16Cpu cpu)
{
OperationUnit = operationUnit;
Instruction = instruction;
ProgramCounter = programCounter;
Cpu = cpu;
}
/// <summary>
/// Parses the upcoming instruction and selects the appropriate OperationUnit from <see cref="OperationRegistry"/>
/// Note that parameters for the executed instruction are obtained at this point in time.
/// </summary>
/// <seealso cref="Operations.IOperationUnit"/>
protected virtual void InstructionDecode()
{
var opCode = (byte)(CurrentInstruction.UnsignedValue >> Word.Size - InstructionLength);
Operations.IOperationUnit unit;
if (OperationRegistry.TryGetValue(opCode, out unit))
{
unit.Reset();
unit.Decode(CurrentInstruction);
OperationUnit = unit;
}
else
{
throw new UnknownInstructionException();
}
}
