Make sure the CPU graph advanced correctly even in turbo mode

Cocoa/Document.m

@@ -288,6 +288,7 @@ static void debuggerReloadCallback(GB_gameboy_t *gb)
     GB_set_user_data(&_gb, (__bridge void *)(self));
     GB_set_boot_rom_load_callback(&_gb, (GB_boot_rom_load_callback_t)boot_rom_load);
     GB_set_vblank_callback(&_gb, (GB_vblank_callback_t) vblank);
+    GB_set_enable_skipped_frame_vblank_callbacks(&_gb, true);
     GB_set_log_callback(&_gb, (GB_log_callback_t) consoleLog);
     GB_set_input_callback(&_gb, (GB_input_callback_t) consoleInput);
     GB_set_async_input_callback(&_gb, (GB_input_callback_t) asyncConsoleInput);
@@ -359,6 +360,12 @@ static void debuggerReloadCallback(GB_gameboy_t *gb)
 
 - (void)vblankWithType:(GB_vblank_type_t)type
 {
+    if (type == GB_VBLANK_TYPE_SKIPPED_FRAME) {
+        double frameUsage = GB_debugger_get_frame_cpu_usage(&_gb);
+        [_cpuView addSample:frameUsage];
+        return;
+    }
+    
     if (_gbsVisualizer) {
         dispatch_async(dispatch_get_main_queue(), ^{
             [_gbsVisualizer setNeedsDisplay:true];

Core/display.c

@@ -197,7 +197,13 @@ void GB_display_vblank(GB_gameboy_t *gb, GB_vblank_type_t type)
     }
     
     if (gb->turbo) {
+#ifndef GB_DISABLE_DEBUGGER
+        if (unlikely(gb->backstep_instructions)) return;
+#endif
         if (GB_timing_sync_turbo(gb)) {
+            if (gb->vblank_callback && gb->enable_skipped_frame_vblank_callbacks) {
+                gb->vblank_callback(gb, GB_VBLANK_TYPE_SKIPPED_FRAME);
+            }
             return;
         }
     }
@@ -2485,3 +2491,8 @@ double GB_get_usual_frame_rate(GB_gameboy_t *gb)
 {
     return GB_get_clock_rate(gb) / (double)LCDC_PERIOD;
 }
+
+void GB_set_enable_skipped_frame_vblank_callbacks(GB_gameboy_t *gb, bool enable)
+{
+    gb->enable_skipped_frame_vblank_callbacks = enable;
+}

Core/display.h

@@ -20,6 +20,7 @@ typedef enum {
     GB_VBLANK_TYPE_LCD_OFF, // An artificial frame pushed while the LCD was off
     GB_VBLANK_TYPE_ARTIFICIAL, // An artificial frame pushed for some other reason
     GB_VBLANK_TYPE_REPEAT, // A frame that would not render on actual hardware, but the screen should retain the previous frame
+    GB_VBLANK_TYPE_SKIPPED_FRAME, // If enabled via GB_set_enable_skipped_frame_vblank_callbacks, called on skipped frames during turbo mode
 } GB_vblank_type_t;
 
 typedef void (*GB_vblank_callback_t)(GB_gameboy_t *gb, GB_vblank_type_t type);
@@ -95,6 +96,7 @@ static const GB_color_correction_mode_t __attribute__((deprecated("Use GB_COLOR_
 static const GB_color_correction_mode_t __attribute__((deprecated("Use GB_COLOR_CORRECTION_MODERN_BOOST_CONTRAST instead"))) GB_COLOR_CORRECTION_PRESERVE_BRIGHTNESS = GB_COLOR_CORRECTION_MODERN_BOOST_CONTRAST;
 
 void GB_set_vblank_callback(GB_gameboy_t *gb, GB_vblank_callback_t callback);
+void GB_set_enable_skipped_frame_vblank_callbacks(GB_gameboy_t *gb, bool enable);
 void GB_set_rgb_encode_callback(GB_gameboy_t *gb, GB_rgb_encode_callback_t callback);
 void GB_set_palette(GB_gameboy_t *gb, const GB_palette_t *palette);
 const GB_palette_t *GB_get_palette(GB_gameboy_t *gb);

Core/gb.h

@@ -833,6 +833,7 @@ struct GB_gameboy_internal_s {
         /* Misc */
         bool turbo;
         bool turbo_dont_skip;
+        bool enable_skipped_frame_vblank_callbacks;
         bool disable_rendering;
         uint8_t boot_rom[0x900];
         bool vblank_just_occured; // For slow operations involving syscalls; these should only run once per vblank