From a05e7f28241d5338b0f3b214ad51c3b926f72a3f Mon Sep 17 00:00:00 2001
From: alyosha-tas <alexei.f.k@gmail.com>
Date: Wed, 19 Jul 2017 19:19:37 -0400
Subject: [PATCH] A7800Hawk: Start Super Game mappers

---
 .../Atari/A7800Hawk/Mappers/MapperSG.cs       | 113 ++++++++++++++++++
 1 file changed, 113 insertions(+)
 create mode 100644 BizHawk.Emulation.Cores/Consoles/Atari/A7800Hawk/Mappers/MapperSG.cs

diff --git a/BizHawk.Emulation.Cores/Consoles/Atari/A7800Hawk/Mappers/MapperSG.cs b/BizHawk.Emulation.Cores/Consoles/Atari/A7800Hawk/Mappers/MapperSG.cs
new file mode 100644
index 0000000000..db327c8312
--- /dev/null
+++ b/BizHawk.Emulation.Cores/Consoles/Atari/A7800Hawk/Mappers/MapperSG.cs
@@ -0,0 +1,113 @@
+using BizHawk.Common;
+using BizHawk.Common.NumberExtensions;
+using System;
+
+namespace BizHawk.Emulation.Cores.Atari.A7800Hawk
+{
+	// Default mapper with no bank switching
+	// Just need to keep track of high score bios stuff
+	public class MapperSG : MapperBase
+	{
+		public byte bank = 0;
+
+		public override byte ReadMemory(ushort addr)
+		{
+			if (addr >= 0x1000 && addr < 0x1800)
+			{
+				//could be hsbios RAM here
+				if (Core._hsbios != null)
+				{
+					return Core._hsram[addr - 0x1000];
+				}
+				return 0xFF;
+			}
+			else if (addr < 0x4000)
+			{
+				// could be either RAM mirror or ROM
+				if (addr >= 0x3000 && Core._hsbios != null)
+				{
+					return Core._hsbios[addr - 0x3000];
+				}
+				else
+				{
+					return Core.RAM[0x800 + addr & 0x7FF];
+				}
+			}
+			else
+			{
+				// cartridge and other OPSYS
+				if (addr >= (0x10000 - Core._bios.Length) && !Core.A7800_control_register.Bit(2))
+				{
+					return Core._bios[addr - (0x10000 - Core._bios.Length)];
+				}
+				else
+				{
+					if (addr >=0xC000)
+					{
+						// bank 7 is fixed
+						return Core._rom[Core._rom.Length - (0x10000 - addr)];
+					}
+					else if (addr >= 0x8000)
+					{
+						// reutrn whatever bank is there
+						int temp_addr = addr - 0x8000;
+
+						return Core._rom[temp_addr + bank * 0x4000];
+					}
+					else
+					{
+						// return bank 6
+						int temp_addr = addr - 0x4000;
+						return Core._rom[temp_addr + 6 * 0x4000];
+					}				
+				}
+			}
+		}
+
+		public override byte PeekMemory(ushort addr)
+		{
+			return ReadMemory(addr);
+		}
+
+		public override void WriteMemory(ushort addr, byte value)
+		{
+			if (addr >= 0x1000 && addr < 0x1800)
+			{
+				//could be hsbios RAM here
+				if (Core._hsbios != null)
+				{
+					Core._hsram[addr - 0x1000] = value;
+				}
+			}
+			else if (addr < 0x4000)
+			{
+				// could be either RAM mirror or ROM
+				if (addr >= 0x3000 && Core._hsbios != null)
+				{
+				}
+				else
+				{
+					Core.RAM[0x800 + addr & 0x7FF] = value;
+				}
+			}
+			else
+			{
+				// cartridge and other OPSYS
+				if (addr>=0x8000)
+				{
+					bank = value;
+				}
+			}
+		}
+
+		public override void PokeMemory(ushort addr, byte value)
+		{
+			WriteMemory(addr, value);
+		}
+
+		public override void SyncState(Serializer ser)
+		{
+			ser.Sync("Bank", ref bank);
+		}
+	}
+}