Exemplo n.º 1
0
        private int GetAddress(AddressModes addressMode, int SignatureBytes, RegisterBankNumber Bank)
        {
            int addr = 0;
            int ptr  = 0;

            switch (addressMode)
            {
            // The address will not be used in Immediate or Implied mode, but
            case AddressModes.Immediate:
                return(ADDRESS_IMMEDIATE);

            case AddressModes.Implied:
                return(ADDRESS_IMPLIED);

            case AddressModes.Absolute:
                return(Bank.GetLongAddress(SignatureBytes));

            case AddressModes.AbsoluteLong:
                return(SignatureBytes);

            case AddressModes.AbsoluteIndexedWithX:
                return(Bank.GetLongAddress(SignatureBytes + cpu.X.Value));

            case AddressModes.AbsoluteLongIndexedWithX:
                return(SignatureBytes + cpu.X.Value);

            case AddressModes.AbsoluteIndexedWithY:
                return(Bank.GetLongAddress(SignatureBytes + cpu.Y.Value));

            case AddressModes.AbsoluteLongIndexedWithY:
                return(Bank.GetLongAddress(SignatureBytes + cpu.X.Value));

            case AddressModes.DirectPage:
                return(cpu.DirectPage.GetLongAddress(SignatureBytes));

            case AddressModes.DirectPageIndexedWithX:
                return(cpu.DirectPage.GetLongAddress(SignatureBytes + cpu.X.Value));

            case AddressModes.DirectPageIndexedWithY:
                return(cpu.DirectPage.GetLongAddress(SignatureBytes + cpu.Y.Value));

            case AddressModes.DirectPageIndexedIndirectWithX:
                addr = cpu.DirectPage.GetLongAddress(SignatureBytes) + cpu.X.Value;
                ptr  = cpu.MemMgr.ReadWord(addr);
                //return cpu.ProgramBank.GetLongAddress(ptr);
                return((cpu.PC & 0xFF_0000) + ptr);

            case AddressModes.DirectPageIndirect:
                addr = cpu.DirectPage.GetLongAddress(SignatureBytes);
                ptr  = cpu.MemMgr.ReadWord(addr);
                return(cpu.DataBank.GetLongAddress(ptr));

            case AddressModes.DirectPageIndirectIndexedWithY:
                addr = cpu.DirectPage.GetLongAddress(SignatureBytes);
                ptr  = cpu.MemMgr.ReadWord(addr) + cpu.Y.Value;
                //return cpu.ProgramBank.GetLongAddress(ptr);
                return((cpu.PC & 0xFF_0000) + ptr);

            case AddressModes.DirectPageIndirectLong:
                addr = cpu.DirectPage.GetLongAddress(SignatureBytes);
                ptr  = cpu.MemMgr.ReadLong(addr);
                return(ptr);

            case AddressModes.DirectPageIndirectLongIndexedWithY:
                addr = cpu.DirectPage.GetLongAddress(SignatureBytes);
                ptr  = cpu.MemMgr.ReadLong(addr) + cpu.Y.Value;
                return(ptr);

            case AddressModes.ProgramCounterRelative:
                ptr  = MakeSignedByte((byte)SignatureBytes);
                addr = cpu.PC + ptr;
                return(addr);

            case AddressModes.ProgramCounterRelativeLong:
                ptr  = MakeSignedInt((UInt16)SignatureBytes);
                addr = cpu.PC + ptr;
                return(addr);

            case AddressModes.StackImplied:
                //case AddressModes.StackAbsolute:
                return(0);

            case AddressModes.StackDirectPageIndirect:
                return(cpu.DirectPage.GetLongAddress(SignatureBytes));

            case AddressModes.StackRelative:
                return(cpu.Stack.Value + SignatureBytes);

            case AddressModes.StackRelativeIndirectIndexedWithY:
                int bankOffset = Bank.Value << 16;
                addr = bankOffset + (cpu.Stack.Value + SignatureBytes);
                return(bankOffset + cpu.MemMgr.ReadWord(addr) + cpu.Y.Value);

            case AddressModes.StackProgramCounterRelativeLong:
                return(SignatureBytes);

            // Jump and JSR indirect references vectors located in Bank 0
            case AddressModes.JmpAbsoluteIndirect:
                addr = SignatureBytes;
                ptr  = cpu.MemMgr.ReadWord(addr);
                //return cpu.ProgramBank.GetLongAddress(ptr);
                return((cpu.PC & 0xFF_0000) + ptr);

            case AddressModes.JmpAbsoluteIndirectLong:
                addr = SignatureBytes;
                ptr  = cpu.MemMgr.ReadLong(addr);
                return(ptr);

            case AddressModes.JmpAbsoluteIndexedIndirectWithX:
                addr = SignatureBytes + cpu.X.Value;
                //ptr = cpu.Memory.ReadWord(cpu.ProgramBank.GetLongAddress(addr));
                ptr = cpu.MemMgr.ReadWord((cpu.PC & 0xFF_0000) + addr);
                //return cpu.ProgramBank.GetLongAddress(ptr);
                return((cpu.PC & 0xFF_0000) + ptr);

            case AddressModes.Accumulator:
                return(0);

            default:
                throw new NotImplementedException("GetAddress() Address mode not implemented: " + addressMode.ToString());
            }
        }
Exemplo n.º 2
0
 public int GetLongPC()
 {
     return(ProgramBank.GetLongAddress(PC));
 }