Added Mapper number 2 aka UxROM

include/MapperUxROM.h

@@ -0,0 +1,27 @@
+#ifndef MAPPERUXROM_H
+#define MAPPERUXROM_H
+#include "Mapper.h"
+
+namespace sn
+{
+    class MapperUxROM : public Mapper
+    {
+        public:
+            MapperUxROM(Cartridge& cart);
+            void writePRG (Address addr, Byte value);
+            Byte readPRG (Address addr);
+            const Byte* getPagePtr(Address addr);
+
+            Byte readCHR (Address addr);
+            void writeCHR (Address addr, Byte value);
+        private:
+            bool m_usesCharacterRAM;
+
+            const Byte* m_lastBankPtr;
+            Address m_selectPRG;
+
+            std::vector<Byte> m_characterRAM;
+
+    };
+}
+#endif // MAPPERUXROM_H

src/Cartridge.cpp

@@ -101,15 +101,15 @@ namespace sn
         else
             LOG(Info) << "ROM is NTSC compatible.\n";
 
-        //PRG-ROM
+        //PRG-ROM 16KB banks
         m_PRG_ROM.resize(0x4000 * banks);
         if (!romFile.read(reinterpret_cast<char*>(&m_PRG_ROM[0]), 0x4000 * banks))
         {
             LOG(Error) << "Reading PRG-ROM from image file failed." << std::endl;
             return false;
         }
 
-        //CHR-ROM
+        //CHR-ROM 8KB banks
         if (vbanks)
         {
             m_CHR_ROM.resize(0x2000 * vbanks);

src/Mapper.cpp

@@ -1,5 +1,6 @@
 #include "Mapper.h"
 #include "MapperNROM.h"
+#include "MapperUxROM.h"
 
 namespace sn
 {
@@ -11,6 +12,9 @@ namespace sn
             case NROM:
                 ret.reset(new MapperNROM(cart));
                 break;
+            case UxROM:
+                ret.reset(new MapperUxROM(cart));
+                break;
             default:
                 ret.reset(nullptr);
         }

src/MapperUxROM.cpp

@@ -0,0 +1,58 @@
+#include "MapperUxROM.h"
+#include "Log.h"
+
+namespace sn
+{
+    MapperUxROM::MapperUxROM(Cartridge &cart) :
+        Mapper(cart, Mapper::UxROM),
+        m_selectPRG(0)
+    {
+        if (cart.getVROM().size() == 0)
+        {
+            m_usesCharacterRAM = true;
+            m_characterRAM.resize(0x2000);
+            LOG(Info) << "Uses character RAM" << std::endl;
+        }
+        else
+            m_usesCharacterRAM = false;
+
+        m_lastBankPtr = &cart.getROM()[cart.getROM().size() - 0x4000]; //last - 16KB
+    }
+
+    Byte MapperUxROM::readPRG(Address addr)
+    {
+        if (addr < 0xc000)
+            return m_cartridge.getROM()[((addr - 0x8000) & 0x3fff) | (m_selectPRG << 14)];
+        else
+            return *(m_lastBankPtr + (addr & 0x3fff));
+    }
+
+    void MapperUxROM::writePRG(Address addr, Byte value)
+    {
+        m_selectPRG = value;
+    }
+
+    const Byte* MapperUxROM::getPagePtr(Address addr)
+    {
+        if (addr < 0xc000)
+            return &m_cartridge.getROM()[((addr - 0x8000) & 0x3fff) | (m_selectPRG << 14)];
+        else
+            return m_lastBankPtr + (addr & 0x3fff);
+    }
+
+    Byte MapperUxROM::readCHR(Address addr)
+    {
+        if (m_usesCharacterRAM)
+            return m_characterRAM[addr];
+        else
+            return m_cartridge.getVROM()[addr];
+    }
+
+    void MapperUxROM::writeCHR(Address addr, Byte value)
+    {
+        if (m_usesCharacterRAM)
+            m_characterRAM[addr] = value;
+        else
+            LOG(Info) << "Read-only CHR memory write attempt at " << std::hex << addr << std::endl;
+    }
+}