public void Dispatch(Cpu8086 cpu, OpCodeManager.Instruction instruction)
{
if (cpu.GetRegister(Register.CX) == 0)
{
new JumpRelative().Dispatch(cpu, instruction);
}
}
public void Dispatch(Cpu8086 cpu, OpCodeManager.Instruction instruction)
{
var value1 = cpu.GetRegister(Register.AX);
var value2 = InstructionHelper.GetInstructionValue(cpu, instruction.Flag, instruction.SegmentPrefix, instruction.Argument1, instruction.Argument1Value, instruction.Argument1Displacement);
if (instruction.Flag.Has(OpCodeManager.OpCodeFlag.Size8))
{
value1 &= 0xFF;
value2 &= 0xFF;
}
uint result;
switch (instruction.Type)
{
case OpCodeManager.InstructionType.Multiply:
result = (uint)value1 * value2;
break;
case OpCodeManager.InstructionType.SignedMultiply:
result = (uint)(value1 * value2);
break;
default:
throw new ArgumentOutOfRangeException();
}
InstructionHelper.CalculateAddFlags(cpu, instruction.Flag, value1, value2, (int)result);
cpu.SetRegister(Register.AX, (ushort)result);
if (!instruction.Flag.Has(OpCodeManager.OpCodeFlag.Size8))
{
cpu.SetRegister(Register.DX, (ushort)(result >> 16));
}
}
public void Dispatch(Cpu8086 cpu, OpCodeManager.Instruction instruction)
{
switch (instruction.Argument1)
{
case (int)Register.SP:
// 8086 has a bug where it pushes SP after it has been modified
// cpu.registers[(int)Register.SP] -= 2;
// cpu.WriteU16(SegmentToAddress(cpu.GetRegister(Register.SS), cpu.GetRegister(Register.SP)), cpu.GetRegister(Register.SP));
// break;
case (int)Register.AX:
case (int)Register.CX:
case (int)Register.DX:
case (int)Register.BX:
case (int)Register.BP:
case (int)Register.SI:
case (int)Register.DI:
case (int)Register.IP:
case (int)Register.CS:
case (int)Register.DS:
case (int)Register.ES:
case (int)Register.SS:
case unchecked ((int)Register.FLAGS):
cpu.Push(cpu.GetRegister((Register)instruction.Argument1));
break;
case OpCodeManager.ARG_DEREFERENCE:
case OpCodeManager.ARG_MEMORY:
var address = InstructionHelper.GetInstructionRealAddress(cpu, instruction.SegmentPrefix, instruction.Argument1, instruction.Argument1Value, instruction.Argument1Displacement);
cpu.Push(cpu.ReadU16(address));
break;
default:
throw new ArgumentOutOfRangeException();
}
}
public void Dispatch(Cpu8086 cpu, OpCodeManager.Instruction instruction)
{
cpu.DecRegister(Register.CX);
var counter = cpu.GetRegister(Register.CX);
if (counter != 0)
{
new JumpRelative().Dispatch(cpu, instruction);
}
}
public void Dispatch(Cpu8086 cpu, OpCodeManager.Instruction instruction)
{
var port = InstructionHelper.GetInstructionValue(cpu, instruction.Flag, instruction.SegmentPrefix, instruction.Argument1, instruction.Argument1Value, instruction.Argument1Displacement);
var device = cpu.GetPortDevice(port);
if (device == null)
{
throw new InvalidOperationException($"Tried to write to port 0x{port.ToString("X")}");
}
if (instruction.Flag.Has(OpCodeManager.OpCodeFlag.Size8))
{
//Console.WriteLine($"OUT {port.ToString("X")}:{cpu.GetRegister(Register.AL).ToString("X")}");
device.Write(port, (byte)cpu.GetRegister(Register.AL));
}
else
{
device.Write16(port, cpu.GetRegister(Register.AX));
}
}
public void Dispatch(Cpu8086 cpu, OpCodeManager.Instruction instruction)
{
cpu.SetRegister(Register.IP, cpu.Pop());
if (instruction.Argument1 == OpCodeManager.ARG_CONSTANT)
{
cpu.SetRegister(Register.SP, (ushort)(cpu.GetRegister(Register.SP) + instruction.Argument1Value));
}
else
{
Debug.Assert(instruction.Argument1 == OpCodeManager.ARG_NONE);
}
}
public void Dispatch(Cpu8086 cpu, OpCodeManager.Instruction instruction)
{
var value1 = (int)(((uint)cpu.GetRegister(Register.DX) << 16) | cpu.GetRegister(Register.AX));
int value2 = (short)InstructionHelper.GetInstructionValue(cpu, instruction.Flag, instruction.SegmentPrefix, instruction.Argument1, instruction.Argument1Value, instruction.Argument1Displacement);
if ((uint)value1 == 0x80000000 || value2 == 0)
{
cpu.Interrupt(0);
return;
}
var quotient = value1 / value2;
var remainder = value1 % value2;
if ((quotient & 0xFFFF) != quotient)
{
cpu.Interrupt(0);
return;
}
cpu.SetRegister(Register.AX, (ushort)quotient);
cpu.SetRegister(Register.DX, (ushort)remainder);
}
public void Dispatch(Cpu8086 cpu, OpCodeManager.Instruction instruction)
{
var segment = Register.DS;
if (instruction.SegmentPrefix != Register.Invalid)
{
segment = instruction.SegmentPrefix;
}
var sourceAddress = InstructionHelper.SegmentToAddress(cpu.GetRegister(segment), cpu.GetRegister(Register.SI));
var destAddress = InstructionHelper.SegmentToAddress(cpu.GetRegister(Register.ES), cpu.GetRegister(Register.DI));
byte size;
if (instruction.Flag.Has(OpCodeManager.OpCodeFlag.Size8))
{
var value = cpu.ReadU8(sourceAddress);
cpu.WriteU8(destAddress, value);
size = 1;
}
else
{
var value = cpu.ReadU16(sourceAddress);
cpu.WriteU16(destAddress, value);
size = 2;
}
if (!cpu.GetFlags().Has(FlagsRegister.Direction))
{
cpu.IncRegister(Register.DI, size);
cpu.IncRegister(Register.SI, size);
}
else
{
cpu.DecRegister(Register.DI, size);
cpu.DecRegister(Register.SI, size);
}
}
public void Dispatch(Cpu8086 cpu, OpCodeManager.Instruction instruction)
{
byte size;
if (instruction.Flag.Has(OpCodeManager.OpCodeFlag.Size8))
{
cpu.WriteU8(InstructionHelper.SegmentToAddress(cpu.GetRegister(Register.ES), cpu.GetRegister(Register.DI)), (byte)(cpu.GetRegister(Register.AX) & 0xFF));
size = 1;
}
else
{
cpu.WriteU16(InstructionHelper.SegmentToAddress(cpu.GetRegister(Register.ES), cpu.GetRegister(Register.DI)), cpu.GetRegister(Register.AX));
size = 2;
}
if (!cpu.GetFlags().Has(FlagsRegister.Direction))
{
cpu.IncRegister(Register.DI, size);
}
else
{
cpu.DecRegister(Register.DI, size);
}
}
public void Dispatch(Cpu8086 cpu, OpCodeManager.Instruction instruction)
{
var segment = Register.DS;
if (instruction.SegmentPrefix != Register.Invalid)
{
segment = instruction.SegmentPrefix;
}
ushort value1;
ushort value2;
byte size;
if (instruction.Flag.Has(OpCodeManager.OpCodeFlag.Size8))
{
value1 = cpu.ReadU8(InstructionHelper.SegmentToAddress(cpu.GetRegister(segment), cpu.GetRegister(Register.SI)));
value2 = cpu.ReadU8(InstructionHelper.SegmentToAddress(cpu.GetRegister(Register.ES), cpu.GetRegister(Register.DI)));
size = 1;
}
else
{
value1 = cpu.ReadU16(InstructionHelper.SegmentToAddress(cpu.GetRegister(segment), cpu.GetRegister(Register.SI)));
value2 = cpu.ReadU16(InstructionHelper.SegmentToAddress(cpu.GetRegister(Register.ES), cpu.GetRegister(Register.DI)));
size = 2;
}
var result = value1 - value2;
InstructionHelper.CalculateSubFlags(cpu, instruction.Flag, value1, value2, result);
if (!cpu.GetFlags().Has(FlagsRegister.Direction))
{
cpu.SetRegister(Register.DI, (ushort)(cpu.GetRegister(Register.DI) + size));
cpu.SetRegister(Register.SI, (ushort)(cpu.GetRegister(Register.SI) + size));
}
else
{
cpu.SetRegister(Register.DI, (ushort)(cpu.GetRegister(Register.DI) - size));
cpu.SetRegister(Register.SI, (ushort)(cpu.GetRegister(Register.SI) - size));
}
}
private ushort ProcessExchangeSecond(Cpu8086 cpu, OpCodeManager.Instruction instruction, ushort value)
{
ushort tmp;
switch (instruction.Argument2)
{
case (int)Register.AX:
case (int)Register.CX:
case (int)Register.DX:
case (int)Register.BX:
case (int)Register.SP:
case (int)Register.BP:
case (int)Register.SI:
case (int)Register.DI:
case (int)Register.IP:
case (int)Register.CS:
case (int)Register.DS:
case (int)Register.ES:
case (int)Register.SS:
tmp = cpu.GetRegister((Register)instruction.Argument2);
cpu.SetRegister((Register)instruction.Argument2, (byte)value);
break;
case OpCodeManager.ARG_BYTE_REGISTER:
tmp = cpu.GetRegisterU8((Register)instruction.Argument2Value);
cpu.SetRegisterU8((Register)instruction.Argument2Value, (byte)value);
break;
case OpCodeManager.ARG_DEREFERENCE:
case OpCodeManager.ARG_MEMORY:
var address = InstructionHelper.GetInstructionRealAddress(cpu, instruction.SegmentPrefix, instruction.Argument2, instruction.Argument2Value, instruction.Argument2Displacement);
tmp = cpu.ReadU16(address);
cpu.WriteU16(address, value);
break;
default:
throw new NotImplementedException();
}
return(tmp);
}
public void Dispatch(Cpu8086 cpu, OpCodeManager.Instruction instruction)
{
uint value1 = cpu.GetRegister(Register.AX);
uint value2 = (byte)InstructionHelper.GetInstructionValue(cpu, instruction.Flag, instruction.SegmentPrefix, instruction.Argument1, instruction.Argument1Value, instruction.Argument1Displacement);
if (value2 == 0)
{
cpu.Interrupt(0);
return;
}
var quotient = value1 / value2;
if (quotient > 0xFF)
{
cpu.Interrupt(0);
return;
}
var remainder = value1 % value2;
cpu.SetRegisterU8(Register.AL, (byte)quotient);
cpu.SetRegisterU8(Register.AH, (byte)remainder);
}
public void Dispatch(Cpu8086 cpu, OpCodeManager.Instruction instruction)
{
cpu.SetRegister(Register.DX, (cpu.GetRegister(Register.AX) & 0x8000) != 0 ? (ushort)0xFFFF : (ushort)0);
}
public void Dispatch(Cpu8086 cpu, OpCodeManager.Instruction instruction)
{
ushort counter;
switch (instruction.OpcodePrefix)
{
case 0:
new OneStringOperation().Dispatch(cpu, instruction);
break;
case 0xF2:
counter = cpu.GetRegister(Register.CX);
if (instruction.Type == OpCodeManager.InstructionType.Cmps || instruction.Type == OpCodeManager.InstructionType.Scas)
{
while (counter != 0)
{
new OneStringOperation().Dispatch(cpu, instruction);
counter--;
if (cpu.GetFlags().Has(FlagsRegister.Zero))
{
break;
}
}
}
else
{
while (counter != 0)
{
new OneStringOperation().Dispatch(cpu, instruction);
counter--;
}
}
cpu.SetRegister(Register.CX, counter);
break;
case 0xF3:
counter = cpu.GetRegister(Register.CX);
if (instruction.Type == OpCodeManager.InstructionType.Cmps || instruction.Type == OpCodeManager.InstructionType.Scas)
{
while (counter != 0)
{
new OneStringOperation().Dispatch(cpu, instruction);
counter--;
if (!cpu.GetFlags().Has(FlagsRegister.Zero))
{
break;
}
}
}
else
{
while (counter != 0)
{
new OneStringOperation().Dispatch(cpu, instruction);
counter--;
}
}
cpu.SetRegister(Register.CX, counter);
break;
default:
throw new NotImplementedException();
}
}
public void Dispatch(Cpu8086 cpu, OpCodeManager.Instruction instruction)
{
Debug.Assert(instruction.Argument1 == OpCodeManager.ARG_CONSTANT);
cpu.Push(cpu.GetRegister(Register.IP));
cpu.SetRegister(Register.IP, (ushort)(cpu.GetRegister(Register.IP) + instruction.Argument1Value));
}
public void Dispatch(Cpu8086 cpu, OpCodeManager.Instruction instruction)
{
switch (instruction.Argument1)
{
case (int)Register.AX:
case (int)Register.CX:
case (int)Register.DX:
case (int)Register.BX:
case (int)Register.SP:
case (int)Register.BP:
case (int)Register.SI:
case (int)Register.DI:
case (int)Register.IP:
case (int)Register.CS:
case (int)Register.DS:
case (int)Register.ES:
case (int)Register.SS:
cpu.SetRegister((Register)instruction.Argument1, ProcessExchangeSecond(cpu, instruction, cpu.GetRegister((Register)instruction.Argument1)));
break;
case OpCodeManager.ARG_BYTE_REGISTER:
cpu.SetRegister((Register)instruction.Argument1Value, (byte)ProcessExchangeSecond(cpu, instruction, cpu.GetRegisterU8((Register)instruction.Argument1Value)));
break;
default:
throw new NotImplementedException();
}
}
public void Dispatch(Cpu8086 cpu, OpCodeManager.Instruction instruction)
{
cpu.Push(cpu.GetRegister(Register.CS));
cpu.Push(cpu.GetRegister(Register.IP));
new FarJump().Dispatch(cpu, instruction);
}
public void Dispatch(Cpu8086 cpu, OpCodeManager.Instruction instruction)
{
var address = InstructionHelper.SegmentToAddress(cpu.GetRegister(Register.DS), (ushort)(cpu.GetRegister(Register.BX) + cpu.GetRegisterU8(Register.AL)));
cpu.SetRegisterU8(Register.AL, cpu.ReadU8(address));
}
public int GetCurrentAddress()
{
return(_cpu.GetRegister(Register.CS) * 0x10 + _cpu.GetRegister(Register.IP));
}