Fix for issue #59

src/backend/Core.cpp

@@ -34,7 +34,7 @@ void Core::LoadROM(const std::string& rom_) {
   GameDB::match(cpu->mem);
   cpu->mem.mmio.vi.isPal = cpu->mem.IsROMPAL();
   cpu->mem.mmio.si.pif.InitDevices(cpu->mem.saveType);
-  cpu->mem.mmio.si.pif.LoadMempak(rom);
+  cpu->mem.mmio.si.pif.mempakPath = rom;
   cpu->mem.mmio.si.pif.LoadEeprom(cpu->mem.saveType, rom);
   cpu->mem.flash.Load(cpu->mem.saveType, rom);
   cpu->mem.LoadSRAM(cpu->mem.saveType, rom);

src/backend/core/mmio/PIF.cpp

@@ -27,33 +27,36 @@ void PIF::Reset() {
   }
 }
 
-void PIF::LoadMempak(const std::string& path) {
+void PIF::MaybeLoadMempak() {
-  mempakPath = fs::path(path).replace_extension(".mempak").string();
+  if(!mempakOpen) {
-  std::error_code error;
+    mempakPath = fs::path(mempakPath).replace_extension(".mempak").string();
-  if (mempak.is_mapped()) {
+    std::error_code error;
-    mempak.sync(error);
+    if (mempak.is_mapped()) {
-    if (error) { Util::panic("Could not sync {}", mempakPath); }
+      mempak.sync(error);
-    mempak.unmap();
+      if (error) { Util::panic("Could not sync {}", mempakPath); }
-  }
+      mempak.unmap();
-  FILE* f = fopen(mempakPath.c_str(), "rb");
+    }
-  if (!f) {
+    FILE *f = fopen(mempakPath.c_str(), "rb");
-    f = fopen(mempakPath.c_str(), "wb");
+    if (!f) {
-    u8* dummy = (u8*)calloc(MEMPAK_SIZE, 1);
+      f = fopen(mempakPath.c_str(), "wb");
-    fwrite(dummy, 1, MEMPAK_SIZE, f);
+      u8 *dummy = (u8 *) calloc(MEMPAK_SIZE, 1);
-    free(dummy);
+      fwrite(dummy, 1, MEMPAK_SIZE, f);
-  }
+      free(dummy);
+    }
 
-  fseek(f, 0, SEEK_END);
+    fseek(f, 0, SEEK_END);
-  size_t actualSize = ftell(f);
+    size_t actualSize = ftell(f);
-  fseek(f, 0, SEEK_SET);
+    fseek(f, 0, SEEK_SET);
-  if (actualSize != MEMPAK_SIZE) {
+    if (actualSize != MEMPAK_SIZE) {
-    Util::panic("Corrupt mempak!");
+      Util::panic("Corrupt mempak!");
-  }
+    }
-  fclose(f);
+    fclose(f);
 
-  mempak = mio::make_mmap_sink(
+    mempak = mio::make_mmap_sink(
     mempakPath, 0, mio::map_entire_file, error);
-  if (error) { Util::panic("Could not open {}", mempakPath); }
+    if (error) { Util::panic("Could not open {}", mempakPath); }
+    mempakOpen = true;
+  }
 }
 
 FORCE_INLINE size_t getSaveSize(SaveType saveType) {
@@ -247,7 +250,8 @@ void PIF::ProcessCommands(Mem &mem) {
   }
 }
 
-void PIF::MempakRead(const u8* cmd, u8* res) const {
+void PIF::MempakRead(const u8* cmd, u8* res) {
+  MaybeLoadMempak();
   u16 offset = cmd[3] << 8;
   offset |= cmd[4];
 
@@ -274,6 +278,7 @@ void PIF::MempakRead(const u8* cmd, u8* res) const {
 }
 
 void PIF::MempakWrite(u8* cmd, u8* res) {
+  MaybeLoadMempak();
   // First two bytes in the command are the offset
   u16 offset = cmd[3] << 8;
   offset |= cmd[4];

src/backend/core/mmio/PIF.hpp

@@ -107,7 +107,7 @@ struct PIF {
   PIF() = default;
   ~PIF() = default;
   void Reset();
-  void LoadMempak(const std::string&);
+  void MaybeLoadMempak();
   void LoadEeprom(SaveType, const std::string&);
   void ProcessCommands(Mem&);
   void InitDevices(SaveType);
@@ -118,12 +118,12 @@ struct PIF {
   void UpdateController();
   bool ReadButtons(u8*) const;
   void ControllerID(u8*) const;
-  void MempakRead(const u8*, u8*) const;
+  void MempakRead(const u8*, u8*);
   void MempakWrite(u8*, u8*);
   void EepromRead(const u8*, u8*, const Mem&) const;
   void EepromWrite(const u8*, u8*, const Mem&);
 
-  bool gamepadConnected = false;
+  bool gamepadConnected = false, mempakOpen = false;
   SDL_GameController* gamepad{};
   JoybusDevice joybusDevices[6]{};
   u8 bootrom[PIF_BOOTROM_SIZE]{}, ram[PIF_RAM_SIZE]{};