Add feature to cache ISOs in RAM to avoid I/O stutters. 64-bit only. Loading gets slow though.

TODO: Make it cache in the background on load. Allow on 32-bit for small ISOs.

Core/Config.cpp

@@ -295,6 +295,7 @@ static ConfigSetting generalSettings[] = {
 	// "default" means let emulator decide, "" means disable.
 	ConfigSetting("ReportingHost", &g_Config.sReportHost, "default"),
 	ConfigSetting("AutoSaveSymbolMap", &g_Config.bAutoSaveSymbolMap, false),
+	ConfigSetting("CacheFullIsoInRam", &g_Config.bCacheFullIsoInRam, false),
 
 #ifdef ANDROID
 	ConfigSetting("ScreenRotation", &g_Config.iScreenRotation, 1),

Core/Config.h

@@ -112,6 +112,7 @@ public:
 	bool bAtomicAudioLocks;
 	int iLockedCPUSpeed;
 	bool bAutoSaveSymbolMap;
+	bool bCacheFullIsoInRam;
 	int iScreenRotation;
 
 	std::string sReportHost;

Core/FileSystems/BlockDevices.cpp

@@ -44,6 +44,20 @@ BlockDevice *constructBlockDevice(const char *filename) {
 		return new FileBlockDevice(f);
 }
 
+RAMBlockDevice::RAMBlockDevice(BlockDevice *device) {
+	totalBlocks_ = device->GetNumBlocks();
+	u32 blockSize = GetBlockSize();
+	image_ = new u8[totalBlocks_ * blockSize];
+	for (int i = 0; i < totalBlocks_; i++) {
+		device->ReadBlock(i, image_ + i * blockSize);
+	}
+	delete device;
+}
+
+RAMBlockDevice::~RAMBlockDevice() {
+	delete[] image_;
+}
+
 
 // Android NDK does not support 64-bit file I/O using C streams
 // so we fall back onto syscalls

Core/FileSystems/BlockDevices.h

@@ -63,8 +63,8 @@ class FileBlockDevice : public BlockDevice
 public:
 	FileBlockDevice(FILE *file);
 	~FileBlockDevice();
-	bool ReadBlock(int blockNumber, u8 *outPtr);
-	u32 GetNumBlocks() {return (u32)(filesize / GetBlockSize());}
+	bool ReadBlock(int blockNumber, u8 *outPtr) override;
+	u32 GetNumBlocks() override {return (u32)(filesize / GetBlockSize());}
 
 private:
 #ifdef ANDROID
@@ -91,8 +91,8 @@ public:
 	NPDRMDemoBlockDevice(FILE *file);
 	~NPDRMDemoBlockDevice();
 
-	bool ReadBlock(int blockNumber, u8 *outPtr);
-	u32 GetNumBlocks() {return (u32)lbaSize;}
+	bool ReadBlock(int blockNumber, u8 *outPtr) override;
+	u32 GetNumBlocks() override {return (u32)lbaSize;}
 
 private:
 	FILE *f;
@@ -112,5 +112,31 @@ private:
 	u8 *tempBuf;
 };
 
+// This simply fully reads another block device and caches it in RAM.
+// A bit slow to initialize.
+class RAMBlockDevice : public BlockDevice
+{
+public:
+	RAMBlockDevice(BlockDevice *device);
+	~RAMBlockDevice();
+
+	bool ReadBlock(int blockNumber, u8 *outPtr) override {
+		if (blockNumber >= 0 && blockNumber < totalBlocks_) {
+			u32 blockSize = GetBlockSize();
+			memcpy(outPtr, image_ + blockSize * blockNumber, blockSize);
+			return true;
+		}
+		return false;
+	}
+
+	u32 GetNumBlocks() override {
+		return totalBlocks_;
+	}
+
+private:
+	int totalBlocks_;
+	u8 *image_;
+};
+
 
 BlockDevice *constructBlockDevice(const char *filename);

Core/PSPLoaders.cpp

@@ -71,6 +71,12 @@ void InitMemoryForGameISO(std::string fileToStart) {
 		// Can't init anything without a block device...
 		if (!bd)
 			return;
+
+		if (g_Config.bCacheFullIsoInRam) {
+			// The constructor destroys the original block device object after reading it.
+			bd = new RAMBlockDevice(bd);
+		}
+
 		umd2 = new ISOFileSystem(&pspFileSystem, bd);
 		actualIso = true;
 	}

UI/GameSettingsScreen.cpp

@@ -391,6 +391,10 @@ void GameSettingsScreen::CreateViews() {
 	systemSettings->Add(new CheckBox(&g_Config.bBypassOSKWithKeyboard, s->T("Enable Windows native keyboard", "Enable Windows native keyboard")));
 #endif
 
+#if defined(_M_X64)
+	systemSettings->Add(new CheckBox(&g_Config.bCacheFullIsoInRam, s->T("Cache ISO in RAM", "Cache full ISO in RAM (slow startup)")));
+#endif
+
 	systemSettings->Add(new ItemHeader(s->T("Developer Tools")));
 	systemSettings->Add(new Choice(s->T("Developer Tools")))->OnClick.Handle(this, &GameSettingsScreen::OnDeveloperTools);