From e208b147ae345310323680d01ffafb6a63452876 Mon Sep 17 00:00:00 2001
From: beirich <beirich@4bbf4f03-6f44-549e-7e59-35d4b0962838>
Date: Sun, 16 Sep 2012 04:42:14 +0000
Subject: [PATCH] gen: support save-ram. but not eeprom, yet.

---
 .../Consoles/Sega/Genesis/Cart/SaveRAM.cs     | 34 +++++++++++++++----
 .../Consoles/Sega/Genesis/MemoryMap.68000.cs  | 13 +++++--
 2 files changed, 38 insertions(+), 9 deletions(-)

diff --git a/BizHawk.Emulation/Consoles/Sega/Genesis/Cart/SaveRAM.cs b/BizHawk.Emulation/Consoles/Sega/Genesis/Cart/SaveRAM.cs
index 0ae5bb6c35..c4ccbbf387 100644
--- a/BizHawk.Emulation/Consoles/Sega/Genesis/Cart/SaveRAM.cs
+++ b/BizHawk.Emulation/Consoles/Sega/Genesis/Cart/SaveRAM.cs
@@ -4,7 +4,8 @@ namespace BizHawk.Emulation.Consoles.Sega
 {
     partial class Genesis
     {
-        bool SaveRamEnabled = false;
+        bool SaveRamEnabled;
+        bool SaveRamEveryOtherByte;
         int SaveRamStartOffset;
         int SaveRamEndOffset;
         int SaveRamLength;
@@ -13,14 +14,33 @@ namespace BizHawk.Emulation.Consoles.Sega
 
         void InitializeSaveRam(GameInfo game)
         {
-            if (game["SaveRamOffset"])
+            // TODO if eeprom in use, abort saveram check
+
+            if (game["DisableSaveRam"] || RH_SRamPresent == false)
+                return;
+
+            SaveRamEnabled = true;
+            SaveRamEveryOtherByte = RH_SRamCode != 0;
+            SaveRamStartOffset = RH_SRamStart;
+            SaveRamEndOffset = RH_SRamEnd;
+
+            if (game["SaveRamStartOffset"])
+                SaveRamStartOffset = game.GetHexValue("SaveRamStartOffset");
+            if (game["SaveRamEndOffset"])  
+                SaveRamEndOffset = game.GetHexValue("SaveRamEndOffset");
+
+            SaveRamLength = (SaveRamEndOffset - SaveRamStartOffset) + 1;
+
+            if (SaveRamEveryOtherByte)
             {
-                SaveRamEnabled = true;
-                SaveRamStartOffset = game.GetHexValue("SaveRamOffset");
-                SaveRamLength = game.GetHexValue("SaveRamLength");
-                SaveRamEndOffset = SaveRamStartOffset + SaveRamLength;
-                SaveRAM = new byte[SaveRamLength];
+                SaveRamStartOffset &= 0xFFFFFE;
+                SaveRamEndOffset &= 0xFFFFFE;
+                SaveRamLength = ((SaveRamEndOffset - SaveRamStartOffset) / 2) + 1;
             }
+
+            SaveRAM = new byte[SaveRamLength];
+
+            Console.WriteLine("SaveRAM enabled. Start: ${0:X6} End: ${1:X6} Length: ${2:X} Mode: {3}", SaveRamStartOffset, SaveRamEndOffset, SaveRamLength, RH_SRamInterpretation());
         }
 
 		public byte[] ReadSaveRam() { return (byte[])SaveRAM.Clone(); }
diff --git a/BizHawk.Emulation/Consoles/Sega/Genesis/MemoryMap.68000.cs b/BizHawk.Emulation/Consoles/Sega/Genesis/MemoryMap.68000.cs
index 0350820e11..226ad0733c 100644
--- a/BizHawk.Emulation/Consoles/Sega/Genesis/MemoryMap.68000.cs
+++ b/BizHawk.Emulation/Consoles/Sega/Genesis/MemoryMap.68000.cs
@@ -14,7 +14,12 @@ namespace BizHawk.Emulation.Consoles.Sega
             if (address < 0x400000)
             {
                 if (SaveRamEnabled && address >= SaveRamStartOffset && address < SaveRamEndOffset)
-                    return (sbyte) SaveRAM[address - SaveRamStartOffset];
+                {
+                    if (SaveRamEveryOtherByte)
+                        return (sbyte) SaveRAM[(address - SaveRamStartOffset) >> 1];
+                    else
+                        return (sbyte) SaveRAM[address - SaveRamStartOffset];
+                }
                 return (sbyte)RomData[address];
             }
 
@@ -153,7 +158,11 @@ namespace BizHawk.Emulation.Consoles.Sega
 
             if (SaveRamEnabled && address >= SaveRamStartOffset && address < SaveRamEndOffset)
             {
-                SaveRAM[address - SaveRamStartOffset] = (byte) value;
+                if (SaveRamEveryOtherByte)
+                    SaveRAM[(address - SaveRamStartOffset) >> 1] = (byte) value;
+                else
+                    SaveRAM[address - SaveRamStartOffset] = (byte) value;
+                
                 SaveRamModified = true;
                 return;
             }