static void CPU_InvalidInstruction(object sender, InvalidInstructionEventArgs e)
{
Console.Write("Invalid instruction executed: 0x" + e.Instruction.ToString("X4") + " at 0x" + e.Address.ToString("X4") + "\n>");
e.ContinueExecution = false;
CPU.IsRunning = false;
}
private void CpuOnInvalidInstruction(object sender, InvalidInstructionEventArgs invalidInstructionEventArgs)
{
InvalidInstruction(invalidInstructionEventArgs);
if (breakOnInvalidInstructionToolStripMenuItem.Checked)
{
invalidInstructionEventArgs.ContinueExecution = false;
CPU.IsRunning = false;
}
}
void InvalidInstruction(InvalidInstructionEventArgs eventArgs)
{
if (InvokeRequired)
Invoke(new InvalidInstructionDelegate(InvalidInstruction), eventArgs);
else
{
pictureBox1.Visible = true;
invalidInstructionLabel.Text = "Invalid instruction at 0x" + eventArgs.Address.ToString("X4") +
": 0x" + eventArgs.Instruction.ToString("X4");
invalidInstructionLabel.Visible = true;
if (breakOnInvalidInstructionToolStripMenuItem.Checked)
ResetLayout();
}
}
public void Execute(int CyclesToExecute)
{
if (!IsRunning && CyclesToExecute != -1)
return;
int oldCycles = Cycles;
if (CyclesToExecute == -1)
Cycles = 1;
else
Cycles += CyclesToExecute;
while (Cycles > 0)
{
if (IsOnFire)
Memory[Random.Next(0xFFFF)] = (ushort)Random.Next(0xFFFF);
if (!InterruptQueueEnabled && InterruptQueue.Count > 0 && IA != 0)
{
Memory[--SP] = PC;
Memory[--SP] = A;
PC = IA;
A = InterruptQueue.Dequeue();
InterruptQueueEnabled = true;
}
if (BreakpointHit != null)
{
foreach (var breakpoint in Breakpoints)
{
if (breakpoint.Address == PC)
{
if (breakpointHandled || (CyclesToExecute == -1))
{
breakpointHandled = false;
}
else
{
var bea = new BreakpointEventArgs(breakpoint);
BreakpointHit(this, bea);
if (!bea.ContinueExecution)
{
breakpointHandled = true;
return;
}
}
break;
}
}
}
ushort PCBeforeExecution = PC;
ushort instruction = Memory[PC++];
byte opcode = (byte)(instruction & 0x1F);
byte valueB = (byte)((instruction & 0x3E0) >> 5);
byte valueA = (byte)((instruction & 0xFC00) >> 10);
ushort opA = 0, opB = 0;
opA = Get(valueA);
if (opcode != 0)
{
ushort pc_old = PC, sp_old = SP;
opB = Get(valueB);
PC = pc_old;
SP = sp_old;
}
short opB_s = (short)opB;
short opA_s = (short)opA;
Cycles--;
unchecked
{
switch (opcode)
{
case 0x00: // (nonbasic)
switch (valueB)
{
case 0x01: // JSR a
Cycles -= 2;
Memory[--SP] = PC;
PC = opA;
break;
case 0x08: // INT a
Cycles -= 3;
FireInterrupt(opA);
break;
case 0x09: // IAG a
Set(valueA, IA);
break;
case 0x0A: // IAS a
IA = opA;
break;
case 0x0B: // RFI a
A = Memory[SP++];
PC = Memory[SP++];
InterruptQueueEnabled = false;
break;
case 0x0C: // IAQ a
Cycles--;
InterruptQueueEnabled = opA != 0;
break;
case 0x10: // HWN a
Cycles--;
Set(valueA, (ushort)Devices.Count);
break;
case 0x11: // HWQ a
Cycles -= 3;
if (opA < Devices.Count)
{
Device d = Devices[opA];
A = (ushort)(d.DeviceID & 0xFFFF);
B = (ushort)((d.DeviceID & 0xFFFF0000) >> 16);
C = d.Version;
X = (ushort)(d.ManufacturerID & 0xFFFF);
Y = (ushort)((d.ManufacturerID & 0xFFFF0000) >> 16);
}
break;
case 0x12: // HWI a
Cycles -= 3;
if (opA < Devices.Count)
Cycles -= Devices[opA].DoInterrupt();
break;
default:
if (InvalidInstruction != null)
{
var eventArgs = new InvalidInstructionEventArgs(instruction, PCBeforeExecution);
PC = PCBeforeExecution;
InvalidInstruction(this, eventArgs);
if (!eventArgs.ContinueExecution)
return;
}
break;
}
break;
case 0x01: // SET b, a
Set(valueB, opA);
break;
case 0x02: // ADD b, a
Cycles--;
if (opB + opA > 0xFFFF)
EX = 0x0001;
else
EX = 0;
Set(valueB, (ushort)(opB + opA));
break;
case 0x03: // SUB b, a
Cycles--;
if (opB - opA < 0)
EX = 0xFFFF;
else
EX = 0;
Set(valueB, (ushort)(opB - opA));
break;
case 0x04: // MUL b, a
Cycles--;
EX = (ushort)(((opB * opA) >> 16) & 0xffff);
Set(valueB, (ushort)(opB * opA));
break;
case 0x05: // MLI b, a
Cycles--;
EX = (ushort)(((opB_s * opA_s) >> 16) & 0xffff);
Set(valueB, (ushort)(opB_s * opA_s));
break;
case 0x06: // DIV b, a
Cycles -= 2;
if (opA == 0)
{
EX = 0;
Set(valueB, 0);
}
else
{
EX = (ushort)(((opB << 16) / opA) & 0xffff);
Set(valueB, (ushort)(opB / opA));
}
break;
case 0x07: // DVI b, a
Cycles -= 2;
if (opA_s == 0)
{
EX = 0;
Set(valueB, 0);
}
else
{
EX = (ushort)(((opB_s << 16) / opA_s) & 0xffff);
Set(valueB, (ushort)(opB_s / opA_s));
}
break;
case 0x08: // MOD b, a
Cycles -= 2;
if (opA == 0)
Set(valueB, 0);
else
Set(valueB, (ushort)(opB % opA));
break;
case 0x09: // MDI b, a
Cycles -= 2;
if (opA_s == 0)
Set(valueB, 0);
else
Set(valueB, (ushort)(opB_s % opA_s));
break;
case 0x0A: // AND b, a
Set(valueB, (ushort)(opB & opA));
break;
case 0x0B: // BOR b, a
Set(valueB, (ushort)(opB | opA));
break;
case 0x0C: // XOR b, a
Set(valueB, (ushort)(opB ^ opA));
break;
case 0x0D: // SHR b, a
EX = (ushort)(((opB << 16) >> opA) & 0xffff);
Set(valueB, (ushort)(opB >> opA));
break;
case 0x0E: // ASR b, a
EX = (ushort)(((opB_s << 16) >> opA) & 0xffff);
Set(valueB, (ushort)(opB_s >> opA));
break;
case 0x0F: // SHL b, a
EX = (ushort)(((opB << opA) >> 16) & 0xffff);
Set(valueB, (ushort)(opB << opA));
break;
case 0x10: // IFB b, a
Cycles -= 2;
Get(valueB);
if (!((ushort)(opB & opA) != 0))
SkipIfChain();
break;
case 0x11: // IFC b, a
Cycles -= 2;
Get(valueB);
if (!((ushort)(opB & opA) == 0))
SkipIfChain();
break;
case 0x12: // IFE b, a
Cycles -= 2;
Get(valueB);
if (!(opB == opA))
SkipIfChain();
break;
case 0x13: // IFN b, a
Cycles -= 2;
Get(valueB);
if (!(opB != opA))
SkipIfChain();
break;
case 0x14: // IFG b, a
Cycles -= 2;
Get(valueB);
if (!(opB > opA))
SkipIfChain();
break;
case 0x15: // IFA b, a
Cycles -= 2;
Get(valueB);
if (!(opB_s > opA_s))
SkipIfChain();
break;
case 0x16: // IFL b, a
Cycles -= 2;
Get(valueB);
if (!(opB < opA))
SkipIfChain();
break;
case 0x17: // IFU b, a
Cycles -= 2;
Get(valueB);
if (!(opB_s < opA_s))
SkipIfChain();
break;
case 0x1A: // ADX b, a
Cycles -= 2;
uint resADX = (uint)(opB + opA + (short)EX);
EX = (ushort)((resADX >> 16) & 0xFFFF);
Set(valueB, (ushort)resADX);
break;
case 0x1B: // SBX b, a
Cycles -= 2;
uint resSBX = (uint)(opB - opA + (short)EX);
EX = (ushort)((resSBX >> 16) & 0xFFFF);
Set(valueB, (ushort)resSBX);
break;
case 0x1E: // STI b, a
Cycles--;
Set(valueB, opA);
I++;
J++;
break;
case 0x1F: // STD b, a
Cycles--;
Set(valueB, opA);
I--;
J--;
break;
default:
// According to spec, should take zero cycles
// For sanity, all NOPs take one cycle
if (InvalidInstruction != null)
{
var eventArgs = new InvalidInstructionEventArgs(instruction, PCBeforeExecution);
PC = PCBeforeExecution;
InvalidInstruction(this, eventArgs);
if (!eventArgs.ContinueExecution)
return;
}
break;
}
}
if (!IsRunning && CyclesToExecute != -1)
return;
}
if (CyclesToExecute == -1)
{
TotalCycles += -(Cycles - 1);
Cycles = oldCycles;
}
else
TotalCycles += CyclesToExecute;
}