Adding some comments.

src/xenia/emulator.h

@@ -43,33 +43,57 @@ class Window;
 
 namespace xe {
 
+// The main type that runs the whole emulator.
+// This is responsible for initializing and managing all the various subsystems.
 class Emulator {
  public:
   explicit Emulator(const std::wstring& command_line);
   ~Emulator();
 
+  // Full command line used when launching the process.
   const std::wstring& command_line() const { return command_line_; }
 
+  // Window used for displaying graphical output.
   ui::Window* display_window() const { return display_window_; }
 
+  // Guest memory system modelling the RAM (both virtual and physical) of the
+  // system.
   Memory* memory() const { return memory_.get(); }
 
+  // Active debugger, which may or may not be attached.
   debug::Debugger* debugger() const { return debugger_.get(); }
 
+  // Virtualized processor that can execute PPC code.
   cpu::Processor* processor() const { return processor_.get(); }
+  
+  // Audio hardware emulation for decoding and playback.
   apu::AudioSystem* audio_system() const { return audio_system_.get(); }
+  
+  // GPU emulation for command list processing.
   gpu::GraphicsSystem* graphics_system() const {
     return graphics_system_.get();
   }
+  
+  // Human-interface Device (HID) adapters for controllers.
   hid::InputSystem* input_system() const { return input_system_.get(); }
 
+  // Kernel function export table used to resolve exports when JITing code.
   cpu::ExportResolver* export_resolver() const {
     return export_resolver_.get();
   }
+  
+  // File systems mapped to disc images, folders, etc for games and save data.
   vfs::VirtualFileSystem* file_system() const { return file_system_.get(); }
 
+  // The 'kernel', tracking all kernel objects and other state.
+  // This is effectively the guest operating system.
   kernel::KernelState* kernel_state() const { return kernel_state_.get(); }
 
+  // Initializes the emulator and configures all components.
+  // The given window is used for display and the provided functions are used
+  // to create subsystems as required.
+  // Once this function returns a game can be launched using one of the Launch
+  // functions.
   X_STATUS Setup(
       ui::Window* display_window,
       std::function<std::unique_ptr<apu::AudioSystem>(cpu::Processor*)>
@@ -79,9 +103,19 @@ class Emulator {
       std::function<std::vector<std::unique_ptr<hid::InputDriver>>(ui::Window*)>
           input_driver_factory);
 
+  // Launches a game from the given file path.
+  // This will attempt to infer the type of the given file (such as an iso, etc)
+  // using heuristics.
   X_STATUS LaunchPath(std::wstring path);
+  
+  // Launches a game from a .xex file by mounting the containing folder as if it
+  // was an extracted STFS container.
   X_STATUS LaunchXexFile(std::wstring path);
+  
+  // Launches a game from a disc image file (.iso, etc).
   X_STATUS LaunchDiscImage(std::wstring path);
+  
+  // Launches a game from an STFS container file.
   X_STATUS LaunchStfsContainer(std::wstring path);
 
  private: