fix cart detection for 512K ROMs

add new event & hotkey for selecting previous multicart ROM

docs/index.html

@@ -1749,9 +1749,15 @@
       <td>Control + 1</td>
     </tr>
 
+    <tr>
+      <td>Load <i>previous</i> game in ROM (multicart ROM, TIA mode)</td>
+      <td>Shift-Control + r</td>
+      <td>Shift-Control + r</td>
+    </tr>
+
     <tr>
       <td>Reload current ROM (singlecart ROM, TIA mode)<br>
-        Load next game in ROM (multicart ROM, TIA mode)</td>
+        Load <i>next</i> game in ROM (multicart ROM, TIA mode)</td>
       <td>Control + r</td>
       <td>Control + r</td>
     </tr>

src/common/PKeyboardHandler.cxx

@@ -459,6 +459,7 @@ PhysicalKeyboardHandler::EventMappingArray PhysicalKeyboardHandler::DefaultCommo
   {Event::Quit,                     KBDK_Q, KBDM_CTRL},
 #endif
   {Event::ReloadConsole,            KBDK_R, KBDM_CTRL},
+  {Event::PreviousMultiCartRom,     KBDK_R, KBDM_SHIFT | KBDM_CTRL},
 
   {Event::VidmodeDecrease,          KBDK_MINUS, MOD3},
   {Event::VidmodeIncrease,          KBDK_EQUALS, MOD3},

src/emucore/CartDetector.cxx

@@ -218,6 +218,14 @@ CartDetector::createFromMultiCart(const ByteBuffer& image, size_t& size,
 {
   // Get a piece of the larger image
   uInt32 i = settings.getInt("romloadcount");
+
+  // Move to the next game
+  if(!settings.getBool("romloadprev"))
+    i = (i + 1) % numroms;
+  else
+    i = (i - 1) % numroms;
+  settings.setValue("romloadcount", i);
+
   size /= numroms;
   ByteBuffer slice = make_unique<uInt8[]>(size);
   std::copy_n(image.get()+i*size, size, slice.get());
@@ -228,9 +236,6 @@ CartDetector::createFromMultiCart(const ByteBuffer& image, size_t& size,
   buf << " [G" << (i+1) << "]";
   id = buf.str();
 
-  // Move to the next game the next time this ROM is loaded
-  settings.setValue("romloadcount", (i+1)%numroms);
-
   if(size <= 2_KB)       type = Bankswitch::Type::_2K;
   else if(size == 4_KB)  type = Bankswitch::Type::_4K;
   else if(size == 8_KB)  type = Bankswitch::Type::_F8;
@@ -529,7 +534,13 @@ Bankswitch::Type CartDetector::autodetectType(const ByteBuffer& image, size_t si
   }
   else if(size == 512_KB)
   {
-    if(isProbablyTVBoy(image, size))
+    if(isProbably3EX(image, size))
+      type = Bankswitch::Type::_3EX;
+    else if(isProbably3E(image, size))
+      type = Bankswitch::Type::_3E;
+    else if(isProbably3F(image, size))
+      type = Bankswitch::Type::_3F;
+    else if(isProbablyTVBoy(image, size))
       type = Bankswitch::Type::_TVBOY;
   }
   else  // what else can we do?

src/emucore/Event.hxx

@@ -123,7 +123,7 @@ class Event
       ToggleFrameStats, ToggleSAPortOrder, ExitGame,
       // add new events from here to avoid that user remapped events get overwritten
       SettingDecrease, SettingIncrease, PreviousSetting, NextSetting,
-      ToggleAdaptRefresh,
+      ToggleAdaptRefresh, PreviousMultiCartRom,
 
       LastType
     };

src/emucore/EventHandler.cxx

@@ -544,7 +544,11 @@ void EventHandler::handleEvent(Event::Type event, Int32 value, bool repeated)
       return;
 
     case Event::ReloadConsole:
-      if(pressed && !repeated) myOSystem.reloadConsole();
+      if(pressed && !repeated) myOSystem.reloadConsole(true);
+      return;
+
+    case Event::PreviousMultiCartRom:
+      if(pressed && !repeated) myOSystem.reloadConsole(false);
       return;
 
     case Event::VolumeDecrease:
@@ -2172,6 +2176,7 @@ void EventHandler::exitEmulation(bool checkLauncher)
 EventHandler::EmulActionList EventHandler::ourEmulActionList = { {
   { Event::Quit,                    "Quit",                                  "" },
   { Event::ReloadConsole,           "Reload current ROM/load next game",     "" },
+  { Event::PreviousMultiCartRom,    "Load previous multicart game",          "" },
   { Event::ExitMode,                "Exit current Stella menu/mode",         "" },
   { Event::OptionsMenuMode,         "Enter Options menu UI",                 "" },
   { Event::CmdMenuMode,             "Toggle Commands menu UI",               "" },
@@ -2409,7 +2414,7 @@ const Event::EventSet EventHandler::MiscEvents = {
   // Event::MouseAxisXMove, Event::MouseAxisYMove,
   // Event::MouseButtonLeftValue, Event::MouseButtonRightValue,
   Event::HandleMouseControl, Event::ToggleGrabMouse,
-  Event::ToggleSAPortOrder,
+  Event::ToggleSAPortOrder, Event::PreviousMultiCartRom
 };
 
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

src/emucore/EventHandler.hxx

@@ -525,7 +525,7 @@ class EventHandler
     #else
       REFRESH_SIZE         = 0,
     #endif
-      EMUL_ACTIONLIST_SIZE = 156 + PNG_SIZE + COMBO_SIZE + REFRESH_SIZE,
+      EMUL_ACTIONLIST_SIZE = 157 + PNG_SIZE + COMBO_SIZE + REFRESH_SIZE,
       MENU_ACTIONLIST_SIZE = 18
     ;
 

src/emucore/OSystem.cxx

@@ -399,7 +399,7 @@ string OSystem::createConsole(const FilesystemNode& rom, const string& md5sum,
     // Each time a new console is loaded, we simulate a cart removal
     // Some carts need knowledge of this, as they behave differently
     // based on how many power-cycles they've been through since plugged in
-    mySettings->setValue("romloadcount", 0);
+    mySettings->setValue("romloadcount", -1); // we move to the next game initially
   }
 
   // Create an instance of the 2600 game console
@@ -474,8 +474,10 @@ string OSystem::createConsole(const FilesystemNode& rom, const string& md5sum,
 }
 
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
-bool OSystem::reloadConsole()
+bool OSystem::reloadConsole(bool nextrom)
 {
+  mySettings->setValue("romloadprev", !nextrom);
+
   return createConsole(myRomFile, myRomMD5, false) == EmptyString;
 }
 

src/emucore/OSystem.hxx

@@ -345,9 +345,11 @@ class OSystem
       Reloads the current console (essentially deletes and re-creates it).
       This can be thought of as a real console off/on toggle.
 
+      @param nextrom  If true select next multicart ROM, else previous one
+
       @return  True on successful creation, otherwise false
     */
-    bool reloadConsole();
+    bool reloadConsole(bool nextrom = true);
 
     /**
       Creates a new ROM launcher, to select a new ROM to emulate.