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)
{
var value1 = InstructionHelper.GetInstructionValue(cpu, instruction.Flag, instruction.SegmentPrefix, instruction.Argument1, instruction.Argument1Value, instruction.Argument1Displacement);
var value2 = InstructionHelper.GetInstructionValue(cpu, instruction.Flag, instruction.SegmentPrefix, instruction.Argument2, instruction.Argument2Value, instruction.Argument2Displacement);
if (instruction.Flag.Has(OpCodeManager.OpCodeFlag.Size8))
{
value1 &= 0xFF;
value2 &= 0xFF;
}
int result;
bool carry;
switch (instruction.Type)
{
case OpCodeManager.InstructionType.Adc:
result = value1 + value2 + (cpu.GetFlags().Has(FlagsRegister.Carry) ? 1 : 0);
InstructionHelper.CalculateAddFlags(cpu, instruction.Flag, value1, value2, result);
break;
case OpCodeManager.InstructionType.Add:
result = value1 + value2;
InstructionHelper.CalculateAddFlags(cpu, instruction.Flag, value1, value2, result);
break;
case OpCodeManager.InstructionType.And:
case OpCodeManager.InstructionType.Test:
result = value1 & value2;
InstructionHelper.CalculateBitwiseFlags(cpu, instruction.Flag, value1, value2, result);
break;
case OpCodeManager.InstructionType.Compare:
case OpCodeManager.InstructionType.Subtract:
result = value1 - value2;
InstructionHelper.CalculateSubFlags(cpu, instruction.Flag, value1, value2, result);
break;
case OpCodeManager.InstructionType.Or:
result = value1 | value2;
InstructionHelper.CalculateBitwiseFlags(cpu, instruction.Flag, value1, value2, result);
break;
case OpCodeManager.InstructionType.Rcl:
if (instruction.Flag.Has(OpCodeManager.OpCodeFlag.Size8))
{
const int mask = 0x1FF;
var shift = (value2 & 0x1F) % 9;
result = (byte)value1;
if (cpu.Flags.Has(FlagsRegister.Carry))
{
result |= 0x100;
}
result = (byte)(result << shift) | (byte)(result >> (-shift & mask));
if ((result & 0x100) != 0)
{
cpu.Flags |= FlagsRegister.Carry;
}
else
{
cpu.Flags &= ~FlagsRegister.Carry;
}
if (value2 == 1)
{
if (((result & 0x100) != 0) ^ ((result & 0x80) != 0))
{
cpu.Flags |= FlagsRegister.Overflow;
}
else
{
cpu.Flags &= ~FlagsRegister.Overflow;
}
}
}
else
{
const int mask = 0x1FFFF;
var shift = (value2 & 0x1F) % 17;
result = value1;
if (cpu.Flags.Has(FlagsRegister.Carry))
{
result |= 0x10000;
}
result = (ushort)(result << shift) | (ushort)(result >> (-shift & mask));
if ((result & 0x10000) != 0)
{
cpu.Flags |= FlagsRegister.Carry;
}
else
{
cpu.Flags &= ~FlagsRegister.Carry;
}
if (value2 == 1)
{
if (((result & 0x10000) != 0) ^ ((result & 0x8000) != 0))
{
cpu.Flags |= FlagsRegister.Overflow;
}
else
{
cpu.Flags &= ~FlagsRegister.Overflow;
}
}
}
InstructionHelper.CalculateBitwiseFlags(cpu, instruction.Flag, value1, value2, result);
break;
case OpCodeManager.InstructionType.Rcr:
if (instruction.Flag.Has(OpCodeManager.OpCodeFlag.Size8))
{
const int mask = 0x1FF;
var shift = (value2 & 0x1F) % 9;
result = (byte)value1;
if (cpu.Flags.Has(FlagsRegister.Carry))
{
result |= 0x100;
}
if ((result & 0x1) != 0)
{
cpu.Flags |= FlagsRegister.Carry;
}
else
{
cpu.Flags &= ~FlagsRegister.Carry;
}
result = (byte)(result >> shift) | (byte)(result << (-shift & mask));
if (value2 == 1)
{
if (((result & 0x80) != 0) ^ ((result & 0x40) != 0))
{
cpu.Flags |= FlagsRegister.Overflow;
}
else
{
cpu.Flags &= ~FlagsRegister.Overflow;
}
}
}
else
{
const int mask = 0x1FFFF;
var shift = (value2 & 0x1F) % 17;
result = value1;
if (cpu.Flags.Has(FlagsRegister.Carry))
{
result |= 0x10000;
}
if ((result & 0x1) != 0)
{
cpu.Flags |= FlagsRegister.Carry;
}
else
{
cpu.Flags &= ~FlagsRegister.Carry;
}
result = (ushort)(result >> shift) | (ushort)(result << (-shift & mask));
if (value2 == 1)
{
if (((result & 0x8000) != 0) ^ ((result & 0x4000) != 0))
{
cpu.Flags |= FlagsRegister.Overflow;
}
else
{
cpu.Flags &= ~FlagsRegister.Overflow;
}
}
}
//cpu.CalculateBitwiseFlags(instruction.Flag, value1, value2, result);
break;
case OpCodeManager.InstructionType.Rol:
if (instruction.Flag.Has(OpCodeManager.OpCodeFlag.Size8))
{
const int mask = 0xFF;
var shift = value2 & mask;
result = (byte)(value1 << shift) | (byte)(value1 >> (-shift & mask));
}
else
{
const int mask = 0xFFFF;
var shift = value2 & mask;
result = (ushort)(value1 << shift) | (ushort)(value1 >> (-shift & mask));
}
InstructionHelper.CalculateBitwiseFlags(cpu, instruction.Flag, value1, value2, result);
break;
case OpCodeManager.InstructionType.Ror:
if (instruction.Flag.Has(OpCodeManager.OpCodeFlag.Size8))
{
const int mask = 0xFF;
var shift = value2 & mask;
result = (byte)(value1 >> shift) | (byte)(value1 << (-shift & mask));
}
else
{
const int mask = 0xFFFF;
var shift = value2 & mask;
result = (ushort)(value1 >> shift) | (ushort)(value1 << (-shift & mask));
}
InstructionHelper.CalculateBitwiseFlags(cpu, instruction.Flag, value1, value2, result);
break;
case OpCodeManager.InstructionType.Sbb:
result = value1 - (value2 + (cpu.GetFlags().Has(FlagsRegister.Carry) ? 1 : 0));
InstructionHelper.CalculateSubFlags(cpu, instruction.Flag, value1, value2, result);
break;
case OpCodeManager.InstructionType.Shl:
bool overflow;
result = value1 << (value2 & 0x1F);
InstructionHelper.CalculateBitwiseFlags(cpu, instruction.Flag, value1, (ushort)(value2 & 0x1F), result);
if (instruction.Flag.Has(OpCodeManager.OpCodeFlag.Size8))
{
carry = (result & 0x100) != 0;
overflow = (result & 0x80) != 0;
}
else
{
carry = (result & 0x10000) != 0;
overflow = (result & 0x8000) != 0;
}
if (carry)
{
cpu.Flags |= FlagsRegister.Carry;
}
if ((value2 & 0x1F) == 1 && overflow ^ carry)
{
cpu.Flags |= FlagsRegister.Overflow;
}
break;
case OpCodeManager.InstructionType.Sar:
if (instruction.Flag.Has(OpCodeManager.OpCodeFlag.Size8))
{
carry = (((sbyte)value1 >> ((value2 & 0x1F) - 1)) & 1) != 0;
result = (sbyte)value1 >> (value2 & 0x1F);
}
else
{
carry = (((short)value1 >> ((value2 & 0x1F) - 1)) & 1) != 0;
result = (short)value1 >> (value2 & 0x1F);
}
InstructionHelper.CalculateBitwiseFlags(cpu, instruction.Flag, value1, (ushort)(value2 & 0x1F), result);
if (carry)
{
cpu.Flags |= FlagsRegister.Carry;
}
break;
case OpCodeManager.InstructionType.Shr:
carry = ((value1 >> ((value2 & 0x1F) - 1)) & 1) != 0;
result = value1 >> (value2 & 0x1F);
InstructionHelper.CalculateBitwiseFlags(cpu, instruction.Flag, value1, (ushort)(value2 & 0x1F), result);
if (carry)
{
cpu.Flags |= FlagsRegister.Carry;
}
if ((value2 & 0x1F) == 1)
{
if (instruction.Flag.Has(OpCodeManager.OpCodeFlag.Size8))
{
if ((value1 & 0x80) != 0)
{
cpu.Flags |= FlagsRegister.Overflow;
}
}
else
{
if ((value1 & 0x8000) != 0)
{
cpu.Flags |= FlagsRegister.Overflow;
}
}
}
break;
case OpCodeManager.InstructionType.Xor:
result = value1 ^ value2;
InstructionHelper.CalculateBitwiseFlags(cpu, instruction.Flag, value1, value2, result);
break;
default:
throw new NotImplementedException();
}
var truncResult = instruction.Flag.Has(OpCodeManager.OpCodeFlag.Size8) ? (byte)result : (ushort)result;
if (instruction.Type != OpCodeManager.InstructionType.Compare && instruction.Type != OpCodeManager.InstructionType.Test)
{
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, truncResult);
break;
case OpCodeManager.ARG_BYTE_REGISTER:
cpu.SetRegisterU8((Register)instruction.Argument1Value, (byte)truncResult);
break;
case OpCodeManager.ARG_DEREFERENCE:
case OpCodeManager.ARG_MEMORY:
var address = InstructionHelper.GetInstructionRealAddress(cpu, instruction.SegmentPrefix, instruction.Argument1, instruction.Argument1Value, instruction.Argument1Displacement);
if (instruction.Flag.Has(OpCodeManager.OpCodeFlag.Size8))
{
cpu.WriteU8(address, (byte)truncResult);
}
else
{
cpu.WriteU16(address, truncResult);
}
break;
default:
throw new NotImplementedException();
}
}
}