public void Dispatch(Cpu8086 cpu, OpCodeManager.Instruction instruction)
{
var al = cpu.GetRegisterU8(Register.AL);
var flags = cpu.GetFlags();
if ((al & 0xF) > 9 || flags.Has(FlagsRegister.Auxiliary))
{
var ah = cpu.GetRegisterU8(Register.AH);
al = (byte)((al + 6) & 0x0F);
ah++;
cpu.SetRegisterU8(Register.AH, ah);
flags |= FlagsRegister.Carry | FlagsRegister.Auxiliary;
}
else
{
al &= 0x0F;
flags &= ~(FlagsRegister.Carry | FlagsRegister.Auxiliary);
}
flags &= ~(FlagsRegister.Parity | FlagsRegister.Zero | FlagsRegister.Sign);
flags |= (InstructionHelper.ParityLookup[al] ? FlagsRegister.Parity : 0) |
(al == 0 ? FlagsRegister.Zero : 0) |
((al & 0x80) != 0 ? FlagsRegister.Sign : 0);
cpu.SetFlags(flags);
cpu.SetRegisterU8(Register.AL, al);
}
public void Dispatch(Cpu8086 cpu, OpCodeManager.Instruction instruction)
{
ushort value1;
ushort value2;
byte size;
if (instruction.Flag.Has(OpCodeManager.OpCodeFlag.Size8))
{
value1 = cpu.GetRegisterU8(Register.AL);
value2 = cpu.ReadU8(InstructionHelper.SegmentToAddress(cpu.GetRegister(Register.ES), cpu.GetRegister(Register.DI)));
size = 1;
}
else
{
value1 = cpu.GetRegister(Register.AX);
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.IncRegister(Register.DI, size);
}
else
{
cpu.DecRegister(Register.DI, size);
}
}
public void Dispatch(Cpu8086 cpu, OpCodeManager.Instruction instruction)
{
var al = cpu.GetRegisterU8(Register.AL);
var oldAl = al;
var flags = cpu.GetFlags();
var oldCarry = flags.Has(FlagsRegister.Carry);
flags &= ~FlagsRegister.Carry;
if ((al & 0xF) > 9 || flags.Has(FlagsRegister.Auxiliary))
{
al -= 6;
if (oldCarry || (al > oldAl))
{
flags |= FlagsRegister.Carry;
}
else
{
flags &= ~FlagsRegister.Carry;
}
flags |= FlagsRegister.Auxiliary;
}
else
{
flags &= ~FlagsRegister.Auxiliary;
}
if (oldAl > 0x99 || oldCarry)
{
al -= 0x60;
flags |= FlagsRegister.Carry;
}
else
{
flags &= ~FlagsRegister.Carry;
}
flags &= ~(FlagsRegister.Parity | FlagsRegister.Zero | FlagsRegister.Sign);
flags |= (InstructionHelper.ParityLookup[al] ? FlagsRegister.Parity : 0) |
(al == 0 ? FlagsRegister.Zero : 0) |
((al & 0x80) != 0 ? FlagsRegister.Sign : 0);
cpu.SetFlags(flags);
cpu.SetRegister(Register.AL, al);
}
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)
{
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 void Dispatch(Cpu8086 cpu, OpCodeManager.Instruction instruction)
{
cpu.SetRegister(Register.AX, (ushort)(sbyte)cpu.GetRegisterU8(Register.AL));
}
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();
}
}