public bool WriteMemory(ushort addr, ushort value)
{
bool cart = Cart.WriteCart(addr, value);
bool stic = Stic.WriteSTIC(addr, value);
bool psg = Psg.WritePSG(addr, value);
switch (addr & 0xF000)
{
case 0x0000:
if (addr <= 0x007F)
{
// STIC.
break;
}
else if (addr <= 0x00FF)
{
// Unoccupied.
break;
}
else if (addr <= 0x01EF)
{
ScratchpadRam[addr - 0x0100] = (byte)(value & 0x00FF);
return(true);
}
else if (addr <= 0x01FF)
{
// PSG.
break;
}
else if (addr <= 0x035F)
{
SystemRam[addr - 0x0200] = value;
return(true);
}
else if (addr <= 0x03FF)
{
// Read-only garbage values for Intellivision II.
break;
}
else if (addr <= 0x04FF)
{
// Read-only additional EXEC ROM for Intellivision II.
break;
}
break;
case 0x1000:
// Read-only Executive ROM.
break;
case 0x3000:
if (addr <= 0x37FF)
{
// Read-only Graphics ROM.
break;
}
else if (addr <= 0x39FF)
{
// TODO: OK only during VBlank Period 2.
GraphicsRam[addr - 0x3800] = (byte)(value & 0x00FF);
return(true);
}
else if (addr <= 0x3BFF)
{
// TODO: OK only during VBlank Period 2.
GraphicsRam[addr - 0x3A00] = (byte)(value & 0x00FF);
return(true);
}
else if (addr <= 0x3DFF)
{
// TODO: OK only during VBlank Period 2.
GraphicsRam[addr - 0x3C00] = (byte)(value & 0x00FF);
return(true);
}
else
{
// TODO: OK only during VBlank Period 2.
GraphicsRam[addr - 0x3E00] = (byte)(value & 0x00FF);
return(true);
}
case 0x7000:
if (addr <= 0x77FF)
{
// Available to cartridges.
break;
}
else if (addr <= 0x79FF)
{
// TODO: OK only during VBlank Period 2.
GraphicsRam[addr & 0x01FF] = (byte)(value & 0x00FF);
return(true);
}
else if (addr <= 0x7BFF)
{
// TODO: OK only during VBlank Period 2.
GraphicsRam[addr & 0x01FF] = (byte)(value & 0x00FF);
return(true);
}
else if (addr <= 0x7DFF)
{
// TODO: OK only during VBlank Period 2.
GraphicsRam[addr & 0x01FF] = (byte)(value & 0x00FF);
return(true);
}
else
{
// TODO: OK only during VBlank Period 2.
GraphicsRam[addr & 0x01FF] = (byte)(value & 0x00FF);
return(true);
}
case 0x9000:
case 0xA000:
case 0xB000:
if (addr <= 0xB7FF)
{
// Available to cartridges.
break;
}
else if (addr <= 0xB9FF)
{
// TODO: OK only during VBlank Period 2.
GraphicsRam[addr - 0xB800] = (byte)(value & 0x00FF);
return(true);
}
else if (addr <= 0xBBFF)
{
// TODO: OK only during VBlank Period 2.
GraphicsRam[addr - 0xBA00] = (byte)(value & 0x00FF);
return(true);
}
else if (addr <= 0xBDFF)
{
// TODO: OK only during VBlank Period 2.
GraphicsRam[addr - 0xBC00] = (byte)(value & 0x00FF);
return(true);
}
else
{
// TODO: OK only during VBlank Period 2.
GraphicsRam[addr - 0xBE00] = (byte)(value & 0x00FF);
return(true);
}
case 0xF000:
if (addr <= 0xF7FF)
{
// Available to cartridges.
break;
}
else if (addr <= 0xF9FF)
{
// TODO: OK only during VBlank Period 2.
GraphicsRam[addr - 0xF800] = (byte)(value & 0x00FF);
return(true);
}
else if (addr <= 0xFBFF)
{
// TODO: OK only during VBlank Period 2.
GraphicsRam[addr - 0xFA00] = (byte)(value & 0x00FF);
return(true);
}
else if (addr <= 0xFDFF)
{
// TODO: OK only during VBlank Period 2.
GraphicsRam[addr - 0xFC00] = (byte)(value & 0x00FF);
return(true);
}
else
{
// TODO: OK only during VBlank Period 2.
GraphicsRam[addr - 0xFE00] = (byte)(value & 0x00FF);
return(true);
}
}
return(cart || stic || psg);
}
public ushort ReadMemory(ushort addr)
{
ushort?cart = Cart.ReadCart(addr);
ushort?stic = Stic.ReadSTIC(addr);
ushort?psg = Psg.ReadPSG(addr);
ushort?core = null;
switch (addr & 0xF000)
{
case 0x0000:
if (addr <= 0x007F)
{
// STIC.
break;
}
else if (addr <= 0x00FF)
{
// Unoccupied.
break;
}
else if (addr <= 0x01EF)
{
core = (ushort)(ScratchpadRam[addr - 0x0100] & 0x00FF);
}
else if (addr <= 0x01FF)
{
// PSG.
break;
}
else if (addr <= 0x035F)
{
core = SystemRam[addr - 0x0200];
}
else if (addr <= 0x03FF)
{
// TODO: Garbage values for Intellivision II.
break;
}
else if (addr <= 0x04FF)
{
// TODO: Additional EXEC ROM for Intellivision II.
break;
}
break;
case 0x1000:
core = (ushort)(ExecutiveRom[addr - 0x1000] & 0x3FF);
break;
case 0x3000:
if (addr <= 0x37FF)
{
// TODO: OK only during VBlank Period 2.
core = (byte)(GraphicsRom[addr - 0x3000] & 0x00FF);
}
else if (addr <= 0x39FF)
{
// TODO: OK only during VBlank Period 2.
core = (byte)(GraphicsRam[addr - 0x3800] & 0x00FF);
}
else if (addr <= 0x3BFF)
{
// TODO: OK only during VBlank Period 2.
core = (byte)(GraphicsRam[addr - 0x3A00] & 0x00FF);
}
else if (addr <= 0x3DFF)
{
// TODO: OK only during VBlank Period 2.
core = (byte)(GraphicsRam[addr - 0x3C00] & 0x00FF);
}
else
{
// TODO: OK only during VBlank Period 2.
core = (byte)(GraphicsRam[addr - 0x3E00] & 0x00FF);
}
break;
case 0x7000:
if (addr <= 0x77FF)
{
// Available to cartridges.
break;
}
else if (addr <= 0x79FF)
{
// Write-only Graphics RAM.
break;
}
else if (addr <= 0x7BFF)
{
// Write-only Graphics RAM.
break;
}
else if (addr <= 0x7DFF)
{
// Write-only Graphics RAM.
break;
}
else
{
// Write-only Graphics RAM.
break;
}
case 0xB000:
if (addr <= 0xB7FF)
{
// Available to cartridges.
break;
}
else if (addr <= 0xB9FF)
{
// Write-only Graphics RAM.
break;
}
else if (addr <= 0xBBFF)
{
// Write-only Graphics RAM.
break;
}
else if (addr <= 0xBDFF)
{
// Write-only Graphics RAM.
break;
}
else
{
// Write-only Graphics RAM.
break;
}
case 0xF000:
if (addr <= 0xF7FF)
{
// Available to cartridges.
break;
}
else if (addr <= 0xF9FF)
{
// Write-only Graphics RAM.
break;
}
else if (addr <= 0xFBFF)
{
// Write-only Graphics RAM.
break;
}
else if (addr <= 0xFDFF)
{
// Write-only Graphics RAM.
break;
}
else
{
// Write-only Graphics RAM.
break;
}
}
if (cart != null)
{
return((ushort)cart);
}
else if (stic != null)
{
return((ushort)stic);
}
else if (psg != null)
{
return((ushort)psg);
}
else if (core != null)
{
return((ushort)core);
}
return(UNMAPPED);
}