/// <summary>
/// LDA $2000,X
/// </summary>
/// <param name="Address"></param>
/// <param name="bank"></param>
/// <param name="Index">The Index register - maybe short or long.</param>
/// <param name="width">The width of the register requesting data</param>
/// <returns></returns>
private int GetIndexed(int Address, Register bank, Register Index, int width)
{
int addr = Address;
addr = bank.GetLongAddress(Address);
addr = addr + Index.Value;
return((width == 1) ? cpu.MemMgr.ReadByte(addr) : cpu.MemMgr.ReadWord(addr));
}
/// <summary>
/// LDA $2000,X
/// </summary>
/// <param name="Address"></param>
/// <param name="bank"></param>
/// <param name="Index"></param>
/// <returns></returns>
private int GetIndexed(int Address, Register bank, Register Index)
{
int addr = Address;
addr = bank.GetLongAddress(Address);
addr = addr + Index.Value;
return(cpu.Memory.ReadWord(addr));
}
/// <summary>
/// Read memory at specified address. Optionally use bank register
/// to select the relevant bank.
/// </summary>
/// <param name="Address"></param>
/// <param name="bank"></param>
/// <returns></returns>
private int GetAbsolute(int Address, Register bank, int width)
{
return((width == 1) ? cpu.MemMgr.ReadByte(bank.GetLongAddress(Address)) : cpu.MemMgr.ReadWord(bank.GetLongAddress(Address)));
}
/// <summary>
/// Returns a pointer from memory.
/// JMP ($xxxx) reads a two-byte address from bank 0. It jumps to that address in the current
/// program bank (meaning it adds PBR to get the final address.)
/// </summary>
/// <param name="Address">Address of pointer. Final value is address pointer references.</param>
/// <param name="block"></param>
/// <returns></returns>
public int GetAbsoluteIndirectAddress(int Address, Register bank)
{
int ptr = cpu.Memory.ReadWord(Address);
return(bank.GetLongAddress(ptr));
}
/// <summary>
/// Read memory at specified address. Optionally use bank register
/// to select the relevant bank.
/// </summary>
/// <param name="Address"></param>
/// <param name="bank"></param>
/// <returns></returns>
private int GetAbsolute(int Address, Register bank, int bytes)
{
return((bytes == 1) ? cpu.Memory.ReadByte(bank.GetLongAddress(Address)) : cpu.Memory.ReadWord(bank.GetLongAddress(Address)));
}