Add reset key (escape)

src/input.h

@@ -7,6 +7,13 @@
 
 // Emulator Implementation
 
+typedef enum {
+    input_Result_Error  = -1,
+    input_Result_OK     = 0,
+    input_Result_Quit   = 1,
+    input_Result_Reset  = 2,
+} nes_Input_Result;
+
 #define nes_controller_num_buttons  (8U)
 
 typedef enum {

src/nese.c

@@ -142,7 +142,12 @@ int main(int argc, char* argv[]) {
                     // Update button states every rendered frame
                     status = nes_input_update(input, &sys.input);
 
-                    if (status >= 0) {
+                    if (input_Result_Reset == status) {
+                        nes_reset(&sys);
+                        status = 0;
+                    }
+
+                    if (status == 0) {
                         // Update audio, too
                         status = nes_audio_fill(audio, &sys.apu);
                     }

src/sdl_input.c

@@ -48,6 +48,8 @@ static void sdl_input_done(nes_Input_Reader* input) {
     sdl_lose_gamepad(input->data);
 }
 
+static const int sdl_reset_key = SDLK_ESCAPE;
+
 static const int sdl_keycodes[nes_controller_num_buttons] = {
     SDLK_a,
     SDLK_s,
@@ -78,13 +80,12 @@ static int button_index(int keycode, const int* codes) {
 
 static int sdl_input_update(nes_Input_Reader* reader,
                             nes_input* input) {
-    int status = 0;
+    int status = input_Result_OK;
 
     SDL_Event event = {0};
-    while (0 != SDL_PollEvent(&event)) {
+    while (0 == status && 0 != SDL_PollEvent(&event)) {
         if (SDL_QUIT == event.type) {
-            status = -1;
-            break;
+            status = input_Result_Quit;
 
         } else if ( SDL_KEYDOWN == event.type ||
                     SDL_KEYUP == event.type) {
@@ -97,6 +98,10 @@ static int sdl_input_update(nes_Input_Reader* reader,
                 } else {
                     input->controllers[0].buttons &= ~mask;
                 }
+
+            } else if ( event.key.keysym.sym == sdl_reset_key &&
+                        SDL_KEYDOWN == event.type) {
+                status = input_Result_Reset;
             }
 
         } else if ( SDL_CONTROLLERBUTTONDOWN == event.type ||