private static object ReadOperand(QuasarRam memory, ref uint address, AddressingMode am)
{
switch (am)
{
case AddressingMode.DIRECT_REGISTER:
address++;
return((Register)memory[address - 1]);
case AddressingMode.CONDITION_CODE:
address++;
return((byte)memory[address - 1]);
case AddressingMode.INDIRECT_REG8:
case AddressingMode.INDIRECT_REG16:
case AddressingMode.INDIRECT_REG32:
Register reg = (Register)memory[address];
byte[] bytes = new byte[2];
memory.Read(address + 1, 2, 0, bytes);
address += 3;
return(new IndirectOffset(reg, BitConverter.ToInt16(bytes, 0)));
case AddressingMode.IMMEDIATE_32:
address += 4;
return(memory.ReadInt32(address - 4));
}
return(null);
}
public Emulator(QuasarRam memory)
{
Console.WriteLine(memory.Limit.ToString("x8"));
this.memory = memory;
this.peripheralController = new PeripheralController(this);
this.interruptController = new InterruptController();
this.RegisterDevice(this.interruptController);
this.RegisterDevice(this.peripheralController);
this.RegisterDevice(new DeviceIntervalTimer());
}
public static Instruction Fetch(QuasarRam memory, uint address)
{
uint org_add = address;
byte original = memory[address++];
Opcode op = (Opcode)(original & 0x7f);
AddressingMode am1 = AddressingMode.NONE;
AddressingMode am2 = AddressingMode.NONE;
bool hasOperands = ((int)original & 128) == 0;
if (hasOperands)
{
byte descr = memory[address++];
am1 = (AddressingMode)(descr & 0x0F);
am2 = (AddressingMode)((descr & 0xF0) >> 4);
object op1 = ReadOperand(memory, ref address, am1);
object op2 = ReadOperand(memory, ref address, am2);
int size = (int)(address - org_add);
return(new Instruction(op, size, am1, op1, am2, op2));
}
else
{
return(new Instruction(op));
}
}
public Stack(Emulator emu)
{
this.memory = emu.Memory;
this.host = emu;
}