reimplement single threaded mode part1

BasiliskII/src/NOTES

@@ -17,7 +17,7 @@ make
 
 there are two versions:
 - 'worker': uses worker with SharedArrayBuffer. this is the default
-- 'mainthread': doesn't use worker or SAB. to build this version, set the environment variable `macemujs_conf_mainthread=1` when building
+- 'mainthread': (currently broken) doesn't use worker or SAB. to build this version, set the environment variable `macemujs_conf_mainthread=1` when building
 
 
 

BasiliskII/src/SDL/video_sdl.cpp

@@ -142,11 +142,12 @@ static int screen_depth;							// Depth of current screen
 static SDL_Cursor *sdl_cursor;						// Copy of Mac cursor
 static SDL_Color sdl_palette[256];					// Color palette to be used as CLUT and gamma table
 static bool sdl_palette_changed = false;			// Flag: Palette changed, redraw thread must set new colors
-#ifndef EMSCRIPTEN
+#ifndef EMSCRIPTEN_SAB
 // this breaks in clang :(
 static const int sdl_eventmask = SDL_MOUSEEVENTMASK | SDL_KEYEVENTMASK | SDL_VIDEOEXPOSEMASK | SDL_QUITMASK | SDL_ACTIVEEVENTMASK;
 #endif
 
+
 // Mutex to protect SDL events
 static SDL_mutex *sdl_events_lock = NULL;
 #define LOCK_EVENTS SDL_LockMutex(sdl_events_lock)
@@ -1909,14 +1910,27 @@ static int event2keycode(SDL_KeyboardEvent const &ev, bool key_down)
 
 #define SDL_N_EVENTS_PER_HANDLER 1
 
+#ifdef EMSCRIPTEN_MAINTHREAD
+int SDL_PeepEvents(SDL_Event*      events,
+                   int             numevents,
+                   SDL_eventaction action,
+                   Uint32          minType,
+                   Uint32          maxType);
+#endif
+
 static void handle_events(void)
 { 
-	#ifndef EMSCRIPTEN
+	#ifndef EMSCRIPTEN_SAB
 	SDL_Event events[SDL_N_EVENTS_PER_HANDLER];
 	const int n_max_events = sizeof(events) / sizeof(events[0]);
 	int n_events;
 
+#ifdef EMSCRIPTEN_MAINTHREAD
+	while ((n_events = SDL_PeepEvents(events, n_max_events, SDL_GETEVENT, /*SDL_FIRSTEVENT*/0, /*SDL_LASTEVENT*/0xFFFF)) > 0) {
+#else
 	while ((n_events = SDL_PeepEvents(events, n_max_events, SDL_GETEVENT, sdl_eventmask)) > 0) {
+#endif
+
 		for (int i = 0; i < n_events; i++) {
 			SDL_Event const & event = events[i];
 			switch (event.type) {
@@ -2486,6 +2500,8 @@ static void update_display_static_bbox(driver_base *drv)
 	}
 	#endif
 #else
+
+
 	// Allocate bounding boxes for SDL_UpdateRects()
 	const int N_PIXELS = 64;
 	const int n_x_boxes = (VIDEO_MODE_X + N_PIXELS - 1) / N_PIXELS;
@@ -2549,7 +2565,6 @@ static void update_display_static_bbox(driver_base *drv)
 	if (nr_boxes)
 		SDL_UpdateRects(drv->s, nr_boxes, boxes);
 
-
   #ifdef EMSCRIPTEN_EMTERPRET
   	emterpret_frame_count++;
 
@@ -2669,6 +2684,7 @@ static void video_refresh_window_static(void)
 		else
 			update_display_static(drv);
 	}
+
 }
 
 
@@ -2699,12 +2715,8 @@ static void VideoRefreshInit(void)
 
 static inline void do_video_refresh(void)
 {
-	#ifdef EMSCRIPTEN 
-		#ifdef EMSCRIPTEN_MAINTHREAD
-			// TODO implement event handling for mainthread
-		#else
-			sdl_fake_read_input(); 
-		#endif
+	#ifdef EMSCRIPTEN_SAB 
+	sdl_fake_read_input();  
 	#else
 	// Handle SDL events
 	handle_events();
@@ -2726,8 +2738,19 @@ void VideoRefresh(void)
 	if (!redraw_thread_active)
 		return;
 
+
+	int needs_frame = EM_ASM_INT({
+		return Module.needsFrame;
+	});
+
+	if (!needs_frame) return;
+
 	// Process pending events and update display
 	do_video_refresh();
+
+	EM_ASM(
+		Module.drawFrame();
+	);
 }
 
 const int VIDEO_REFRESH_HZ = 60;

BasiliskII/src/Unix/main_unix.cpp

@@ -568,7 +568,7 @@ int fake_main(int argc, char **argv)
 #endif
 #endif
 
-#ifndef EMSCRIPTEN
+#ifndef EMSCRIPTEN_SAB
 #ifdef USE_SDL
 	// Initialize SDL system
 	int sdl_flags = 0;
@@ -587,7 +587,7 @@ int fake_main(int argc, char **argv)
 	}
 	atexit(SDL_Quit);
 #endif
-#endif // not EMSCRIPTEN
+#endif // not EMSCRIPTEN_SAB
 
 	// Init system routines
 	SysInit();

BasiliskII/src/uae_cpu/basilisk_glue.cpp

@@ -33,6 +33,11 @@
 #include "compiler/compemu.h"
 
 
+#ifdef EMSCRIPTEN
+#include <emscripten.h> 
+#endif
+
+
 // RAM and ROM pointers
 uint32 RAMBaseMac = 0;		// RAM base (Mac address space) gb-- initializer is important
 uint8 *RAMBaseHost;			// RAM base (host address space)
@@ -131,22 +136,37 @@ void InitFrameBufferMapping(void)
 #endif
 }
 
+#ifdef EMSCRIPTEN
+static void execution_block() {
+	EM_ASM(
+		Module.startExecutionBlock();
+	);
+	m68k_execute();
+}
+#endif
+
 /*
  *  Reset and start 680x0 emulation (doesn't return)
  */
 
 void Start680x0(void)
 {
-	m68k_reset();
+  m68k_reset();
 #if USE_JIT
     if (UseJIT)
-	m68k_compile_execute();
+  m68k_compile_execute();
     else
 #endif
-	m68k_execute();
+
+#ifdef EMSCRIPTEN_MAINTHREAD
+  emscripten_set_main_loop(execution_block, 0, 1);
+#else
+  m68k_execute();
+#endif
 }
 
 
+
 /*
  *  Trigger interrupt
  */

BasiliskII/src/uae_cpu/newcpu.cpp

@@ -48,6 +48,10 @@ B2_mutex *spcflags_lock = NULL;
 #include "mon_disass.h"
 #endif
 
+#ifdef EMSCRIPTEN
+#include <emscripten.h> 
+#endif
+
 bool quit_program = false;
 struct flag_struct regflags;
 
@@ -1386,9 +1390,50 @@ void m68k_do_execute (void)
 		}
 	}
 }
-
+static int em_execute_depth = 0;
 void m68k_execute (void)
 {
+#ifdef EMSCRIPTEN_MAINTHREAD
+    // if (em_execute_depth > 3) {
+    //   return;
+    // }
+    em_execute_depth++;
+    int cycle_count = 0;
+    double start_time = EM_ASM_DOUBLE({
+      return performance.now();
+    });
+    for (;;) {
+      if (quit_program)
+      break;
+      for (;;) {
+        uae_u32 opcode = GET_OPCODE; 
+        (*cpufunctbl[opcode])(opcode);
+        cpu_check_ticks();
+        if (SPCFLAGS_TEST(SPCFLAG_ALL_BUT_EXEC_RETURN)) {
+          if (m68k_do_specialties())
+            return;
+        }
+        cycle_count++;
+        // every x cycles, check if we've been executing for ideal frame duration
+        if (cycle_count > 20000) {
+          double current_time = EM_ASM_DOUBLE({
+            return performance.now();
+          });
+
+          if (current_time - start_time > 16) {
+            // yield to browser
+            em_execute_depth--;
+            return;
+          } else {
+            cycle_count = 0;
+          }
+        }
+      }
+    }
+    em_execute_depth--;
+
+#else
+
 #if USE_JIT
     ++m68k_execute_depth;
 #endif
@@ -1400,6 +1445,8 @@ void m68k_execute (void)
 #if USE_JIT
     --m68k_execute_depth;
 #endif
+
+#endif
 }
 
 static void m68k_verify (uaecptr addr, uaecptr *nextpc)