add hotkey to decrease current state slot

docs/index.html

@@ -736,13 +736,19 @@
     </tr>
 
     <tr>
-      <td>Switch current state slot</td>
+      <td>Change to previous state slot</td>
+      <td>Shift + F10</td>
+      <td>Shift + F10</td>
+    </tr>
+
+    <tr>
+      <td>Change to next state slot</td>
       <td>F10</td>
       <td>F10</td>
     </tr>
 
     <tr>
-      <td>Automatically switch state slot</td>
+      <td>Automatically change state slot</td>
       <td>Alt + F10</td>
       <td>Cmd + F10</td>
     </tr>
@@ -2243,7 +2249,7 @@
 
     <tr>
       <td><pre>-autoslot &lt;1|0&gt;</pre></td>
-      <td>Automatically switch to the next available save state slot after
+      <td>Automatically change to the next available save state slot after
         saving a ROM state file.</td>
     </tr>
 
@@ -3395,9 +3401,9 @@
             </td>
             <td>-saveonexit</td>
           </tr><tr>
-            <td>Automatically switch...</td>
+            <td>Automatically change...</td>
             <td>
-              Automatically switch to the next available save state slot after saving a ROM state file.
+              Automatically change to the next available save state slot after saving a ROM state file.
             </td>
             <td>-autoslot</td>
           </tr>

src/common/PKeyboardHandler.cxx

@@ -406,7 +406,8 @@ PhysicalKeyboardHandler::EventMappingArray PhysicalKeyboardHandler::DefaultCommo
   {Event::ConsoleRightDiffB,        KBDK_F8},
   {Event::SaveState,                KBDK_F9},
   {Event::SaveAllStates,            KBDK_F9, MOD3},
-  {Event::ChangeState,              KBDK_F10},
+  {Event::PreviousState,            KBDK_F10, KBDM_SHIFT},
+  {Event::NextState,                KBDK_F10},
   {Event::ToggleAutoSlot,           KBDK_F10, MOD3},
   {Event::LoadState,                KBDK_F11},
   {Event::LoadAllStates,            KBDK_F11, MOD3},

src/common/StateManager.cxx

@@ -297,9 +297,13 @@ void StateManager::saveState(int slot)
 }
 
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
-void StateManager::changeState()
+void StateManager::changeState(int direction)
 {
-  myCurrentSlot = (myCurrentSlot + 1) % 10;
+  myCurrentSlot += direction;
+  if (myCurrentSlot < 0)
+    myCurrentSlot = 9;
+  else
+    myCurrentSlot %= 10;
 
   // Print appropriate message
   ostringstream buf;

src/common/StateManager.hxx

@@ -114,9 +114,9 @@ class StateManager
     void saveState(int slot = -1);
 
     /**
-      Switches to the next higher state slot (circular queue style).
+      Switches to the next higher or lower state slot (circular queue style).
     */
-    void changeState();
+    void changeState(int direction);
 
     /**
       Toggles auto slot mode.

src/debugger/gui/DebuggerDialog.cxx

@@ -144,7 +144,8 @@ void DebuggerDialog::handleKeyDown(StellaKey key, StellaMod mod, bool repeated)
 
     case Event::SaveState:
     case Event::SaveAllStates:
-    case Event::ChangeState:
+    case Event::PreviousState :
+    case Event::NextState:
     case Event::LoadState:
     case Event::LoadAllStates:
 

src/emucore/Event.hxx

@@ -93,7 +93,7 @@ class Event
       OptionsMenuMode, CmdMenuMode, DebuggerMode, ExitMode,
       TakeSnapshot, ToggleContSnapshots, ToggleContSnapshotsFrame,
 
-      ChangeState, LoadState, SaveState,
+      NextState, PreviousState, LoadState, SaveState,
       SaveAllStates, LoadAllStates,
       ToggleAutoSlot, ToggleTimeMachine, TimeMachineMode,
       Rewind1Menu, Rewind10Menu, RewindAllMenu,
@@ -134,7 +134,7 @@ class Event
     };
 
     // Event list version, update only if the id of existing(!) event types changed
-    static constexpr Int32 VERSION = 2;
+    static constexpr Int32 VERSION = 3;
 
     using EventSet = std::set<Event::Type>;
 

src/emucore/EventHandler.cxx

@@ -656,8 +656,12 @@ void EventHandler::handleEvent(Event::Type event, Int32 value, bool repeated)
         myOSystem.frameBuffer().showMessage(myOSystem.state().rewindManager().saveAllStates());
       return;
 
-    case Event::ChangeState:
+    case Event::NextState:
-      if(pressed) myOSystem.state().changeState();
+      if(pressed) myOSystem.state().changeState(1);
+      return;
+
+    case Event::PreviousState:
+      if (pressed) myOSystem.state().changeState(-1);
       return;
 
     case Event::ToggleAutoSlot:
@@ -1810,9 +1814,13 @@ EventHandler::EmulActionList EventHandler::ourEmulActionList = { {
   { Event::ConsoleRightDiffB,       "P1 Difficulty B",                       "" },
   { Event::ConsoleRightDiffToggle,  "P1 Toggle Difficulty",                  "" },
   { Event::SaveState,               "Save state",                            "" },
-  { Event::ChangeState,             "Change state slot",                     "" },
+  { Event::SaveAllStates,           "Save all TM states of current game",    "" },
+  { Event::PreviousState,           "Change to previous state slot",         "" },
+  { Event::NextState,               "Change to next state slot",             "" },
   { Event::ToggleAutoSlot,          "Toggle automatic state slot change",    "" },
   { Event::LoadState,               "Load state",                            "" },
+  { Event::LoadAllStates,           "Load saved TM states for current game", "" },
+
 #ifdef PNG_SUPPORT
   { Event::TakeSnapshot,            "Snapshot",                              "" },
   { Event::ToggleContSnapshots,     "Save continuous snapsh. (as defined)",  "" },
@@ -1939,8 +1947,6 @@ EventHandler::EmulActionList EventHandler::ourEmulActionList = { {
   { Event::ToggleGrabMouse,         "Toggle grab mouse",                     "" },
   { Event::ToggleSAPortOrder,       "Swap Stelladaptor port ordering",       "" },
 
-  { Event::SaveAllStates,           "Save all TM states of current game",    "" },
-  { Event::LoadAllStates,           "Load saved TM states for current game", "" },
   { Event::ToggleTimeMachine,       "Toggle 'Time Machine' mode",            "" },
   { Event::TimeMachineMode,         "Toggle 'Time Machine' UI",              "" },
   { Event::RewindPause,             "Rewind one state & enter Pause mode",   "" },
@@ -2026,8 +2032,8 @@ const Event::EventSet EventHandler::AudioVideoEvents = {
 
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 const Event::EventSet EventHandler::StateEvents = {
-  Event::ChangeState, Event::LoadState, Event::SaveState, Event::TimeMachineMode,
+  Event::NextState, Event::PreviousState, Event::LoadState, Event::SaveState,
-  Event::RewindPause, Event::UnwindPause, Event::ToggleTimeMachine,
+  Event::TimeMachineMode, Event::RewindPause, Event::UnwindPause, Event::ToggleTimeMachine,
   Event::Rewind1Menu, Event::Rewind10Menu, Event::RewindAllMenu,
   Event::Unwind1Menu, Event::Unwind10Menu, Event::UnwindAllMenu,
   Event::SaveAllStates, Event::LoadAllStates, Event::ToggleAutoSlot,

src/emucore/EventHandler.hxx

@@ -468,7 +468,7 @@ class EventHandler
     #else
       PNG_SIZE             = 0,
     #endif
-      EMUL_ACTIONLIST_SIZE = 143 + PNG_SIZE + COMBO_SIZE,
+      EMUL_ACTIONLIST_SIZE = 144 + PNG_SIZE + COMBO_SIZE,
       MENU_ACTIONLIST_SIZE = 18
     ;
 

src/emucore/Settings.cxx

@@ -469,7 +469,7 @@ void Settings::usage() const
     << endl
     << "  -saveonexit   <none|current  Automatically save state(s) when exiting emulation\n"
     << "                 all>\n"
-    << "  -autoslot     <1|0>          Automatically switch to next save slot when\n"
+    << "  -autoslot     <1|0>          Automatically change to next save slot when\n"
     << "                                state saving\n"
     << endl
     << "  -rominfo      <rom>          Display detailed information for the given ROM\n"

src/gui/CommandDialog.cxx

@@ -168,7 +168,7 @@ void CommandDialog::handleCommand(CommandSender* sender, int cmd,
 
     case kStateSlotCmd:
     {
-      event = Event::ChangeState;
+      event = Event::NextState;
       stateCmd = true;
       int slot = (instance().state().currentSlot() + 1) % 10;
       updateSlot(slot);

src/gui/DeveloperDialog.cxx

@@ -495,7 +495,7 @@ void DeveloperDialog::addTimeMachineTab(const GUI::Font& font)
   ypos += lineHeight + VGAP;
 
 
-  myAutoSlotWidget = new CheckboxWidget(myTab, font, HBORDER, ypos + 1, "Automatically switch save state slots");
+  myAutoSlotWidget = new CheckboxWidget(myTab, font, HBORDER, ypos + 1, "Automatically change save state slots");
   wid.push_back(myAutoSlotWidget);
   ypos += lineHeight + VGAP;
 

src/gui/MinUICommandDialog.cxx

@@ -191,7 +191,7 @@ void MinUICommandDialog::handleCommand(CommandSender* sender, int cmd,
 
     case kStateSlotCmd:
     {
-      event = Event::ChangeState;
+      event = Event::NextState;
       stateCmd = true;
       int slot = (instance().state().currentSlot() + 1) % 10;
       updateSlot(slot);