From 650019fbffddc815eccf80b83615ba9da89f6f1c Mon Sep 17 00:00:00 2001
From: Souryo <mesenemu@gmail.com>
Date: Wed, 20 Jul 2016 23:17:55 -0400
Subject: [PATCH] Mapper 51 support

---
 Core/Bmc51.h              | 59 +++++++++++++++++++++++++++++++++++++++
 Core/Core.vcxproj         |  1 +
 Core/Core.vcxproj.filters |  3 ++
 Core/MapperFactory.cpp    |  6 ++--
 4 files changed, 67 insertions(+), 2 deletions(-)
 create mode 100644 Core/Bmc51.h

diff --git a/Core/Bmc51.h b/Core/Bmc51.h
new file mode 100644
index 00000000..c6ed1322
--- /dev/null
+++ b/Core/Bmc51.h
@@ -0,0 +1,59 @@
+#pragma once
+#include "stdafx.h"
+#include "BaseMapper.h"
+
+class Bmc51 : public BaseMapper
+{
+private:
+	uint8_t _bank;
+	uint8_t _mode;
+
+protected:
+	virtual uint16_t GetPRGPageSize() { return 0x2000; }
+	virtual uint16_t GetCHRPageSize() { return 0x2000; }
+	uint16_t RegisterStartAddress() { return 0x6000; }
+	uint16_t RegisterEndAddress() { return 0xFFFF; }
+
+	void InitMapper()
+	{
+		_bank = 0;
+		_mode = 1;
+		UpdateState();
+	}
+	
+	void StreamState(bool saving)
+	{
+		BaseMapper::StreamState(saving);
+		Stream(_bank, _mode);
+		if(!saving) {
+			UpdateState();
+		}
+	}
+
+	void UpdateState()
+	{
+		if(_mode & 0x01) {
+			SelectPrgPage4x(0, _bank << 2);
+			SetCpuMemoryMapping(0x6000, 0x7FFF, (0x23 | (_bank << 2)), PrgMemoryType::PrgRom);
+		} else {
+			SelectPrgPage2x(0, (_bank << 2) | _mode);
+			SelectPrgPage2x(1, _bank << 2 | 0x0E);
+			SetCpuMemoryMapping(0x6000, 0x7FFF, (0x2F | (_bank << 2)), PrgMemoryType::PrgRom);
+		}
+
+		SetMirroringType(_mode == 0x03 ? MirroringType::Horizontal : MirroringType::Vertical);
+	}
+
+	void WriteRegister(uint16_t addr, uint8_t value)
+	{
+		if(addr <= 0x7FFF) {
+			_mode = ((value >> 3) & 0x02) | ((value >> 1) & 0x01);
+		} else if(addr >= 0xC000 && addr <= 0xDFFF) {
+			_bank = value & 0x0F;
+			_mode = ((value >> 3) & 0x02) | (_mode & 0x01);
+		} else {
+			_bank = value & 0x0F;
+		}
+		UpdateState();
+	}
+};
\ No newline at end of file
diff --git a/Core/Core.vcxproj b/Core/Core.vcxproj
index 6c1b7fca..5d010d49 100644
--- a/Core/Core.vcxproj
+++ b/Core/Core.vcxproj
@@ -411,6 +411,7 @@
     <ClInclude Include="BaseSoundFilter.h" />
     <ClInclude Include="BF9096.h" />
     <ClInclude Include="BF909x.h" />
+    <ClInclude Include="Bmc51.h" />
     <ClInclude Include="BnRom.h" />
     <ClInclude Include="Caltron41.h" />
     <ClInclude Include="ColorDreams46.h" />
diff --git a/Core/Core.vcxproj.filters b/Core/Core.vcxproj.filters
index 122ac46b..6e4dcc34 100644
--- a/Core/Core.vcxproj.filters
+++ b/Core/Core.vcxproj.filters
@@ -772,6 +772,9 @@
     <ClInclude Include="Bmc235.h">
       <Filter>Nes\Mappers</Filter>
     </ClInclude>
+    <ClInclude Include="Bmc51.h">
+      <Filter>Nes\Mappers</Filter>
+    </ClInclude>
   </ItemGroup>
   <ItemGroup>
     <ClCompile Include="stdafx.cpp">
diff --git a/Core/MapperFactory.cpp b/Core/MapperFactory.cpp
index 9f8d9011..3d843999 100644
--- a/Core/MapperFactory.cpp
+++ b/Core/MapperFactory.cpp
@@ -7,6 +7,8 @@
 #include "AXROM.h"
 #include "Bandai74161_7432.h"
 #include "BandaiFcg.h"
+#include "Bmc51.h"
+#include "Bmc235.h"
 #include "BnRom.h"
 #include "BF909x.h"
 #include "BF9096.h"
@@ -18,7 +20,6 @@
 #include "DaouInfosys.h"
 #include "FDS.h"
 #include "FrontFareast.h"
-#include "Bmc235.h"
 #include "GxRom.h"
 #include "Henggedianzi177.h"
 #include "Henggedianzi179.h"
@@ -138,7 +139,7 @@ Supported mappers:  (... denotes bad mappers, --- denotes potentially bad mapper
 | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10| 11| 12| 13|   | 15|
 | 16| 17| 18| 19|...| 21| 22| 23| 24| 25| 26| 27| 28|   |   | 31|
 | 32| 33| 34|   | 36| 37| 38|---| 40| 41| 42|---| 44| 45| 46| 47|
-| 48| 49| 50|   | 52|   |   |   | 56| 57| 58|   | 60| 61| 62|   |
+| 48| 49| 50| 51| 52|   |   |   | 56| 57| 58|   | 60| 61| 62|   |
 | 64| 65| 66| 67| 68| 69| 70| 71| 72| 73| 74| 75| 76| 77| 78| 79|
 | 80|   | 82|   |   | 85| 86| 87| 88| 89|   | 91| 92| 93| 94| 95|
 |   | 97|   | 99|...|101|   |   |   |   |   |107|   |   |   |   |
@@ -213,6 +214,7 @@ BaseMapper* MapperFactory::GetMapperFromID(RomData &romData)
 		case 48: return new TaitoTc0690();
 		case 49: return new MMC3_49();
 		case 50: return new Mapper50();
+		case 51: return new Bmc51();
 		case 52: return new MMC3_52();
 		case 56: return new Kaiser202();
 		case 57: return new Mapper57();