public void DecimalAdjust(ref byte register, ref byte flags)
{
bool subtract = FlagUtils.GetFlag(Flag.N, flags);
bool carry = FlagUtils.GetFlag(Flag.C, flags);
bool halfCarry = FlagUtils.GetFlag(Flag.H, flags);
if (subtract)
{
if (carry)
{
register -= 0x60;
}
if (halfCarry)
{
register -= 0x6;
}
}
else
{
if (register > 0x99 || carry)
{
register += 0x60;
FlagUtils.SetFlag(Flag.C, true, ref flags);
}
if ((register & 0xF) > 0x9 || halfCarry)
{
register += 0x6;
}
}
FlagUtils.SetFlag(Flag.Z, register == 0x00, ref flags);
FlagUtils.SetFlag(Flag.H, false, ref flags);
}
public void Decrement(ref byte target, ref byte flags)
{
byte origValue = target;
target--;
FlagUtils.SetFlag(Flag.Z, target == 0, ref flags);
FlagUtils.SetFlag(Flag.N, true, ref flags);
FlagUtils.SetFlag(Flag.H, (origValue & 0x0F) < 1, ref flags);
}
public void Increment(ref byte target, ref byte flags)
{
byte origValue = target;
target++;
FlagUtils.SetFlag(Flag.Z, target == 0, ref flags);
FlagUtils.SetFlag(Flag.N, false, ref flags);
FlagUtils.SetFlag(Flag.H, (origValue & 0x0F) + 1 > 0x0F, ref flags);
}
public void DecrementInMemory(byte addrHigh, byte addrLow, ref byte flags)
{
ushort address = BitUtils.BytesToUshort(addrHigh, addrLow);
byte origValue = memory.ReadByte(address);
TickEvent?.Invoke();
memory.WriteByte(address, (byte)(origValue - 1));
FlagUtils.SetFlag(Flag.Z, (byte)(origValue - 1) == 0, ref flags);
FlagUtils.SetFlag(Flag.N, true, ref flags);
FlagUtils.SetFlag(Flag.H, (origValue & 0x0F) < 1, ref flags);
TickEvent?.Invoke();
}
public void AddSigned(ref ushort to, byte value, ref byte flags)
{
ushort originalValue = to;
sbyte valueSigned = unchecked ((sbyte)value);
to = (ushort)(to + valueSigned);
FlagUtils.SetFlag(Flag.Z, false, ref flags);
FlagUtils.SetFlag(Flag.N, false, ref flags);
FlagUtils.SetFlag(Flag.H, (originalValue & 0x0F) + (value & 0x0F) > 0x0F, ref flags);
FlagUtils.SetFlag(Flag.C, (originalValue & 0xFF) + value > 0xFF, ref flags);
TickEvent?.Invoke();
TickEvent?.Invoke();
}
public void Add(ref byte toHigh, ref byte toLow, byte valueHigh, byte valueLow, ref byte flags)
{
ushort to = BitUtils.BytesToUshort(toHigh, toLow);
ushort value = BitUtils.BytesToUshort(valueHigh, valueLow);
ushort result = (ushort)((to + value) & 0xFFFF);
toHigh = BitUtils.MostSignificantByte(result);
toLow = BitUtils.LeastSignificantByte(result);
// Zero flag is not affected
FlagUtils.SetFlag(Flag.N, false, ref flags);
FlagUtils.SetFlag(Flag.H, (to & 0xFFF) + (value & 0xFFF) > 0xFFF, ref flags);
FlagUtils.SetFlag(Flag.C, to + value > 0xFFFF, ref flags);
TickEvent?.Invoke();
}
public void LoadAdjusted(ref byte destHigh, ref byte destLow, ushort value, byte addValue, ref byte flags)
{
ushort originalValue = value;
sbyte signed = unchecked ((sbyte)addValue);
FlagUtils.SetFlag(Flag.C, ((originalValue & 0xFF) + addValue) > 0xFF, ref flags);
FlagUtils.SetFlag(Flag.H, (originalValue & 0x0F) + (addValue & 0x0F) > 0xF, ref flags);
ushort result = (ushort)(value + signed);
destHigh = BitUtils.MostSignificantByte(result);
destLow = BitUtils.LeastSignificantByte(result);
FlagUtils.SetFlag(Flag.Z, false, ref flags);
FlagUtils.SetFlag(Flag.N, false, ref flags);
TickEvent?.Invoke();
}
public void RotateLeftThroughCarry(ref byte register, ref byte flags, bool alwaysResetZero)
{
bool setCarry = register.IsBitSet(7);
RotateLeft(ref register, FlagUtils.GetFlag(Flag.C, flags));
if (alwaysResetZero)
{
FlagUtils.SetFlag(Flag.Z, false, ref flags);
}
else
{
FlagUtils.SetFlag(Flag.Z, register == 0, ref flags);
}
FlagUtils.SetFlag(Flag.N, false, ref flags);
FlagUtils.SetFlag(Flag.H, false, ref flags);
FlagUtils.SetFlag(Flag.C, setCarry, ref flags);
}
public void TestBit(byte register, int index, ref byte flags)
{
FlagUtils.SetFlag(Flag.Z, register.IsBitSet(index) == false, ref flags);
FlagUtils.SetFlag(Flag.N, false, ref flags);
FlagUtils.SetFlag(Flag.H, true, ref flags);
}
public void ComplementCarry(ref byte flags)
{
FlagUtils.SetFlag(Flag.C, !FlagUtils.GetFlag(Flag.C, flags), ref flags);
FlagUtils.SetFlag(Flag.H, false, ref flags);
FlagUtils.SetFlag(Flag.N, false, ref flags);
}
public void Complement(ref byte value, ref byte flags)
{
value = (byte)~value;
FlagUtils.SetFlag(Flag.N, true, ref flags);
FlagUtils.SetFlag(Flag.H, true, ref flags);
}
public void SetCarry(ref byte flags)
{
FlagUtils.SetFlag(Flag.C, true, ref flags);
FlagUtils.SetFlag(Flag.N, false, ref flags);
FlagUtils.SetFlag(Flag.H, false, ref flags);
}
