public void ExecuteJumpReturn(byte instruction, AddressModes addressMode, int signature)
{
RegisterBankNumber fakeBank = new RegisterBankNumber
{
Value = cpu.PC >> 16
};
int addr = GetAddress(addressMode, signature, fakeBank);
switch (instruction)
{
case OpcodeList.JSR_Absolute:
case OpcodeList.JSR_AbsoluteIndexedIndirectWithX:
cpu.Push(cpu.PC - 1, 2);
cpu.JumpLong(addr);
return;
case OpcodeList.JSR_AbsoluteLong:
cpu.Push(cpu.PC - 1, 3);
cpu.JumpLong(addr);
return;
case OpcodeList.JMP_Absolute:
case OpcodeList.JMP_AbsoluteLong:
case OpcodeList.JMP_AbsoluteIndirect:
case OpcodeList.JMP_AbsoluteIndexedIndirectWithX:
case OpcodeList.JMP_AbsoluteIndirectLong:
cpu.JumpLong(addr);
return;
// RTS, RTL, RTI
case OpcodeList.RTI_StackImplied:
cpu.Flags.SetFlags(cpu.Pull(1));
cpu.SyncFlags();
if (cpu.Flags.Emulation)
{
cpu.JumpShort(cpu.Pull(2));
}
else
{
cpu.JumpLong(cpu.Pull(3));
}
return;
case OpcodeList.RTS_StackImplied:
cpu.JumpShort(cpu.Pull(2) + 1);
return;
case OpcodeList.RTL_StackImplied:
addr = cpu.Pull(3);
cpu.JumpLong(addr + 1);
return;
default:
throw new NotImplementedException("ExecuteJumpReturn() opcode not implemented: " + instruction.ToString("X2"));
}
}
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());
}
}
