internal void UpdateTotal(ExecState newExecState)
{
CyclesConsumed += newExecState.CyclesConsumed;
InstructionsExecutionCount += newExecState.InstructionsExecutionCount;
UnknownOpCodeCount += newExecState.UnknownOpCodeCount;
LastOpCodeWasHandled = newExecState.LastOpCodeWasHandled;
LastOpCode = newExecState.LastOpCode;
PCBeforeLastOpCodeExecuted = newExecState.PCBeforeLastOpCodeExecuted;
}
public CPU(ExecState execState)
{
ProcessorStatus = new ProcessorStatus();
ExecState = execState;
// TODO: Inject instruction list?
InstructionList = InstructionList.GetAllInstructions();
// TODO: Inject InstructionExecutor?
_instructionExecutor = new InstructionExecutor();
}
public static ExecState ExecStateAfterInstruction(ulong cyclesConsumed, bool unknownInstruction, byte?lastOpCode, ushort?lastPC)
{
var execState = new ExecState();
execState.InstructionsExecutionCount = 1;
execState.CyclesConsumed = cyclesConsumed;
execState.InstructionsExecutionCount += unknownInstruction?(ulong)1:(ulong)0;
execState.PCBeforeLastOpCodeExecuted = lastPC;
execState.LastOpCode = lastOpCode;
return(execState);
}
public ExecState Execute(
Memory mem,
ExecOptions execOptions)
{
// Collect stats for this invocation of Execute().
// Whereas the property Cpu.ExecState contains the aggregate stats for all invocations of Execute().
var thisExecState = new ExecState();
// Get current cycle count
bool doNextInstruction = true;
while (doNextInstruction)
{
// Fire event before instruction executes
OnInstructionToBeExecuted(new CPUInstructionToBeExecutedEventArgs(this, mem));
// Execute instruction
ushort PCBeforeInstructionExecuted = PC;
var instructionExecutionResult = _instructionExecutor.Execute(this, mem);
// Collect stats for this instruction.
// Whereas the property thisExecState contains the aggregate stats for this invocation of Execute().
// and the property Cpu.ExecState contains the aggregate stats for all invocations of Execute().
var instructionExecState = ExecState.ExecStateAfterInstruction(
cyclesConsumed: instructionExecutionResult.CyclesConsumed,
unknownInstruction: instructionExecutionResult.UnknownInstruction,
lastOpCode: instructionExecutionResult.OpCodeByte,
lastPC: PCBeforeInstructionExecuted
);
// Update/Aggregate total Cpu.ExecState stats
ExecState.UpdateTotal(instructionExecState);
// Update/Aggregate this invocation of Execute() ExecState stats
thisExecState.UpdateTotal(instructionExecState);
// Fire "unknown opcode" or "instruction executed" event
if (instructionExecutionResult.UnknownInstruction)
{
OnUnknownOpCodeDetected(new CPUUnknownOpCodeDetectedEventArgs(this, mem, instructionExecutionResult.OpCodeByte));
Debug.WriteLine($"Unknown opcode: {instructionExecutionResult.OpCodeByte.ToHex()}");
// Check if we're configured to throw exception when unknown exception occurs
if (execOptions.UnknownInstructionThrowsException)
{
throw new DotNet6502Exception($"Unknown opcode: {instructionExecutionResult.OpCodeByte.ToHex()}");
}
}
else
{
OnInstructionExecuted(new CPUInstructionExecutedEventArgs(this, mem));
}
// Check if we should continue executing instructions
if (execOptions.CyclesRequested.HasValue && thisExecState.CyclesConsumed >= execOptions.CyclesRequested.Value)
{
doNextInstruction = false;
}
if (execOptions.MaxNumberOfInstructions.HasValue && thisExecState.InstructionsExecutionCount >= execOptions.MaxNumberOfInstructions.Value)
{
doNextInstruction = false;
}
if (!instructionExecutionResult.UnknownInstruction && execOptions.ExecuteUntilInstruction.HasValue && instructionExecutionResult.OpCodeByte == execOptions.ExecuteUntilInstruction.Value.ToByte())
{
doNextInstruction = false;
}
if (execOptions.ExecuteUntilInstructions.Count > 0 && execOptions.ExecuteUntilInstructions.Contains(instructionExecutionResult.OpCodeByte))
{
doNextInstruction = false;
}
if (execOptions.ExecuteUntilPC.HasValue && PC == execOptions.ExecuteUntilPC.Value)
{
doNextInstruction = false;
}
if (execOptions.ExecuteUntilExecutedInstructionAtPC.HasValue && PCBeforeInstructionExecuted == execOptions.ExecuteUntilExecutedInstructionAtPC.Value)
{
doNextInstruction = false;
}
}
// Return stats for this invocation of Execute();
return(thisExecState);
}