public static void ConditionalReturn(IWriteonlyRegister <ushort> pc, IStack stack, JumpCondition condition, IFlags flags)
{
if (ShouldJump(condition, flags))
{
Return(pc, stack);
}
}
public static void Return(IWriteonlyRegister <ushort> pc, IStack stack)
{
var low = stack.Pop();
var high = stack.Pop();
Load(pc, BitUtils.Combine(low, high));
}
public static void ConditionalJump(IWriteonlyRegister <ushort> target, ushort address, JumpCondition condition, IFlags flags)
{
if (ShouldJump(condition, flags))
{
Load(target, address);
}
}
public static void Pop(IWriteonlyRegister <ushort> target, IStack stack)
{
var low = stack.Pop();
var high = stack.Pop();
target.Value = BitUtils.Combine(low, high);
}
// Used for LDHL SP, e and ADD SP, e
public static void LoadWithSignedOffset(IWriteonlyRegister <ushort> target, IReadonlyRegister <ushort> source, sbyte offset, IFlags flags)
{
var old = source.Value;
target.Value = (ushort)(source.Value + offset);
flags.Zero = false;
flags.Subtract = false;
flags.Carry = (old & 0xFF) + (offset & 0xFF) >= 0x100;
flags.HalfCarry = (old & 0xF) + (offset & 0xF) >= 0x10;
}
public static void Load <T>(IWriteonlyRegister <T> target, T value)
{
target.Value = value;
}
