MemoryMap.Z80.cs

using System;

namespace BizHawk.Emulation.Cores.Sega.Genesis
{
	partial class Genesis
	{
		private int BankRegion;

		public byte ReadMemoryZ80(ushort address)
		{
			if (address < 0x4000)
			{
				//Console.WriteLine("read z80 memory {0:X4}: {1:X2}",address, Z80Ram[address & 0x1FFF]);
				return Z80Ram[address & 0x1FFF];
			}
			if (address >= 0x4000 && address < 0x6000)
			{
				//Console.WriteLine(" === Z80 READS FM STATUS ===");
				return YM2612.ReadStatus(SoundCPU.TotalExecutedCycles); // TODO: more than 1 read port probably?
			}
			if (address >= 0x8000)
			{
				// 68000 Bank region
				return (byte)ReadByte(BankRegion | (address & 0x7FFF));
			}
			if (address <= 0x6100) // read from bank address register - returns FF
				return 0xFF;
			Console.WriteLine("UNHANDLED Z80 READ {0:X4}", address);
			return 0xCD;
		}

		public void WriteMemoryZ80(ushort address, byte value)
		{
			if (address < 0x4000)
			{
				//Console.WriteLine("write z80 memory {0:X4}: {1:X2}",address, value);
				Z80Ram[address & 0x1FFF] = value;
				return;
			}
			if (address >= 0x4000 && address < 0x6000)
			{
				//Console.WriteLine(" === Z80 WRITES YM2612 {0:X4}:{1:X2} ===",address, value);
				YM2612.Write(address & 3, value, SoundCPU.TotalExecutedCycles);
				return;
			}
			if (address < 0x6100)
			{
				BankRegion >>= 1;
				BankRegion |= (value & 1) << 23;
				BankRegion &= 0x00FF8000;
				//Console.WriteLine("Bank pointing at {0:X8}",BankRegion);
				return;
			}
			if (address >= 0x7F00 && address < 0x7F20)
			{
				switch (address & 0x1F)
				{
					case 0x00:
					case 0x02:
						VDP.WriteVdpData((ushort)((value << 8) | value));
						return;

					case 0x04:
					case 0x06:
						VDP.WriteVdpControl((ushort)((value << 8) | value));
						return;

					case 0x11:
					case 0x13:
					case 0x15:
					case 0x17:
						PSG.WritePsgData(value, SoundCPU.TotalExecutedCycles);
						return;
				}
			}
			if (address >= 0x8000)
			{
				WriteByte(BankRegion | (address & 0x7FFF), (sbyte)value);
				return;
			}
			Console.WriteLine("UNHANDLED Z80 WRITE {0:X4}:{1:X2}", address, value);
		}
	}
}