Use Asyncify by default, as replacement for Emterpreter Sync

Emterpreter was removed in Emscripten 1.39.17. The Emterpreter code can run using Asyncify with trivial changes. Since this works well and creates a more fully functioning DOSBox, it is now the default. Use ./configure --disable-asyncify if you don't want it.
dreamlayers · Dec 6, 2022 · af3aef2 · af3aef2
1 parent af97479
commit af3aef2
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Showing 8 changed files with 49 additions and 18 deletions.
diff --git a/configure.ac b/configure.ac
@@ -630,6 +630,14 @@ AC_ARG_ENABLE(
   [], [enable_sync=no])
 AM_CONDITIONAL([EMTERPRETER], [test "x$enable_sync" != "xno"])
 
+AH_TEMPLATE([EM_ASYNCIFY],[Compile using Emscripten asyncify.])
+AC_ARG_ENABLE(
+  [asyncify],
+  [AC_HELP_STRING([--disable-asyncify],
+    [Disable Emscripten asyncify])],
+  [], [enable_asyncify=yes])
+AM_CONDITIONAL([ASYNCIFY], [test "x$enable_asyncify" != "xno"])
+
 AC_ARG_ENABLE(
   [wasm],
   [AC_HELP_STRING([--disable-wasm],
@@ -641,6 +649,7 @@ AM_CONDITIONAL([WEBASSEMBLY], [test "x$enable_wasm" == "xyes"])
 # host compiler, so those flags are set at the end.
 AS_IF([test "x$enable_emscripten" = "xyes"],[
   AS_IF([test "x$enable_sync" != "xno"], [AC_DEFINE([EMTERPRETER_SYNC],[1])])
+  AS_IF([test "x$enable_asyncify" != "xno"], [AC_DEFINE([EM_ASYNCIFY],[1])])
   AS_IF([test "x$with_sdl2" != "xno"],[
     AS_IF([test "x$with_sdl2" = "xyes"],
       [CXXFLAGS="$CXXFLAGS -s USE_SDL=2"],

diff --git a/include/dosbox.h b/include/dosbox.h
@@ -36,7 +36,7 @@ class Section;
 typedef Bitu (LoopHandler)(void);
 
 void DOSBOX_RunMachine();
-#if defined(EMSCRIPTEN) && defined(EMTERPRETER_SYNC)
+#if defined(EMSCRIPTEN) && (defined(EMTERPRETER_SYNC) || defined(EM_ASYNCIFY))
 /* This is for cases where RunMachine is called from code not using
  * emterpreter. There, emscripten_sleep() is prohibited and emulation
  * will be aborted with a timeout error if this takes too long.

diff --git a/src/Makefile.am b/src/Makefile.am
@@ -27,6 +27,9 @@ else
 # Memory init file is huge and it doesn't save bandwith even if using gzip.
 # It is only required when using emterpreter.
 dosbox_LDFLAGS+=--memory-init-file 0
+if ASYNCIFY
+dosbox_LDFLAGS+=-s ASYNCIFY=1 -s FETCH=1
+endif
 endif
 if WEBASSEMBLY
 dosbox_LDFLAGS+=-s WASM=1

diff --git a/src/debug/debug.cpp b/src/debug/debug.cpp
@@ -27,7 +27,7 @@
 #include <iomanip>
 #include <string>
 #include <sstream>
-#if defined(EMSCRIPTEN) && defined(EMTERPRETER_SYNC)
+#if defined(EMSCRIPTEN) && (defined(EMTERPRETER_SYNC) || defined(EM_ASYNCIFY))
 #include <emscripten.h>
 #endif
 using namespace std;
@@ -1826,6 +1826,8 @@ Bitu DEBUG_Loop(void) {
 #if defined(EMSCRIPTEN)
 #if defined(EMTERPRETER_SYNC)
 	emscripten_sleep_with_yield(1);
+#elif defined(EM_ASYNCIFY)
+	emscripten_sleep(1);
 #endif
 #else
 	SDL_Delay(1);

diff --git a/src/dos/dos_programs.cpp b/src/dos/dos_programs.cpp
@@ -23,7 +23,7 @@
 #include <ctype.h>
 #include <string>
 #include <vector>
-#if defined(EMSCRIPTEN) && defined(EMTERPRETER_SYNC)
+#if defined(EMSCRIPTEN) && (defined(EMTERPRETER_SYNC) || defined(EM_ASYNCIFY))
 #include <emscripten.h>
 #include <emscripten/fetch.h>
 #include "dos_inc.h"
@@ -1535,7 +1535,7 @@ static void KEYB_ProgramStart(Program * * make) {
 	*make=new KEYB;
 }
 
-#if defined(EMSCRIPTEN) && defined(EMTERPRETER_SYNC)
+#if defined(EMSCRIPTEN) && (defined(EMTERPRETER_SYNC) || defined(EM_ASYNCIFY))
 class WGET : public Program {
 public:
 	void Run(void);
@@ -1598,7 +1598,12 @@ void WGET::Run(void) {
 		attr.onerror = downloadFailed;
 		fetchdone = false;
 		emscripten_fetch_t *fetch = emscripten_fetch(&attr, url.c_str());
-		while (!fetchdone) emscripten_sleep_with_yield(10);
+		while (!fetchdone)
+#ifdef EMTERPRETER_SYNC
+			emscripten_sleep_with_yield(10);
+#elif defined(EM_ASYNCIFY)
+			emscripten_sleep(10);
+#endif
 		if (fetchsuccess) {
 			Bit16u fhandle;
 			if (!DOS_CreateFile(outname.c_str(),OPEN_WRITE,&fhandle)) {
@@ -1640,7 +1645,7 @@ void WGET::Run(void) {
 static void WGET_ProgramStart(Program * * make) {
 	*make=new WGET;
 }
-#endif // defined(EMSCRIPTEN) && defined(EMTERPRETER_SYNC)
+#endif // defined(EMSCRIPTEN) && (defined(EMTERPRETER_SYNC) || defined(EM_ASYNCIFY))
 
 void DOS_SetupPrograms(void) {
 	/*Add Messages */
@@ -1863,7 +1868,7 @@ void DOS_SetupPrograms(void) {
 	MSG_Add("PROGRAM_KEYB_INVALIDFILE","Keyboard file %s invalid\n");
 	MSG_Add("PROGRAM_KEYB_LAYOUTNOTFOUND","No layout in %s for codepage %i\n");
 	MSG_Add("PROGRAM_KEYB_INVCPFILE","None or invalid codepage file for layout %s\n\n");
-#if defined(EMSCRIPTEN) && defined(EMTERPRETER_SYNC)
+#if defined(EMSCRIPTEN) && (defined(EMTERPRETER_SYNC) || defined(EM_ASYNCIFY))
 	MSG_Add("PROGRAM_WGET_SHOWHELP",
 		"\033[32;1mWGET\033[0m [-o FILENAME] URL\n\n"
 		"Downloads file from URL and saves it to the file system.\n"
@@ -1887,7 +1892,7 @@ void DOS_SetupPrograms(void) {
 	PROGRAMS_MakeFile("LOADROM.COM", LOADROM_ProgramStart);
 	PROGRAMS_MakeFile("IMGMOUNT.COM", IMGMOUNT_ProgramStart);
 	PROGRAMS_MakeFile("KEYB.COM", KEYB_ProgramStart);
-#if defined(EMSCRIPTEN) && defined(EMTERPRETER_SYNC)
+#if defined(EMSCRIPTEN) && (defined(EMTERPRETER_SYNC) || defined(EM_ASYNCIFY))
 	PROGRAMS_MakeFile("WGET.COM", WGET_ProgramStart);
 #endif
 }
diff --git a/src/dosbox.cpp b/src/dosbox.cpp
@@ -137,7 +137,7 @@ Bit32u ticksScheduled;
 bool ticksLocked;
 
 #ifdef EMSCRIPTEN
-#ifdef EMTERPRETER_SYNC
+#if defined(EMTERPRETER_SYNC) || defined(EM_ASYNCIFY)
 int nosleep_lock = 0;
 #else
 static int runcount = 0;
@@ -148,7 +148,7 @@ static Bitu Normal_Loop(void) {
 	Bits ret;
 #ifdef EMSCRIPTEN
 	int ticksEntry = GetTicks();
-#ifdef EMTERPRETER_SYNC
+#if defined(EMTERPRETER_SYNC) || defined(EM_ASYNCIFY)
 	/* Normal DOSBox is free to use up all available host CPU time, but
 	 * in a browser, sleep has to happen regularly so the screen is updated,
 	 * sound isn't interrupted, and the script does not appear to hang.
@@ -158,7 +158,11 @@ static Bitu Normal_Loop(void) {
 	if (SDL_TICKS_PASSED(ticksEntry, last_sleep + 10)) {
 		if (nosleep_lock == 0) {
 			last_sleep = ticksEntry;
+#ifdef EMTERPRETER_SYNC
 			emscripten_sleep_with_yield(1);
+#elif defined(EM_ASYNCIFY)
+			emscripten_sleep(1);
+#endif
 			ticksEntry = GetTicks();
 		} else if (SDL_TICKS_PASSED(ticksEntry, last_sleep + 2000) &&
 		           !SDL_TICKS_PASSED(ticksEntry, last_loop + 200)) {
@@ -360,10 +364,14 @@ static Bitu Normal_Loop(void) {
 			ticksAdded = 0;
 #ifndef EMSCRIPTEN
 			SDL_Delay(1);
-#elif defined(EMTERPRETER_SYNC)
+#elif defined(EMTERPRETER_SYNC) || defined(EM_ASYNCIFY)
 			if (nosleep_lock == 0) {
 				last_sleep = ticksNew;
+#ifdef EMTERPRETER_SYNC
 				emscripten_sleep_with_yield(1);
+#elif defined(EM_ASYNCIFY)
+				emscripten_sleep(1);
+#endif
 			}
 #endif
 			ticksDone -= GetTicks() - ticksNew;
@@ -417,7 +425,7 @@ static void em_main_loop(void) {
 #endif
 
 void DOSBOX_RunMachine(void){
-#if defined(EMSCRIPTEN) && !defined(EMTERPRETER_SYNC)
+#if defined(EMSCRIPTEN) && !defined(EMTERPRETER_SYNC) && !defined(EM_ASYNCIFY)
 	if (runcount == 0) {
 		runcount = 1;
 	} else if (runcount == 1) {
@@ -434,7 +442,7 @@ void DOSBOX_RunMachine(void){
 	Bitu ret;
 	do {
 		ret=(*loop)();
-#if defined(EMSCRIPTEN) && !defined(EMTERPRETER_SYNC)
+#if defined(EMSCRIPTEN) && !defined(EMTERPRETER_SYNC) && !defined(EM_ASYNCIFY)
 		/* These should be very short operations, like interrupts.
 		 * Anything taking a long time will probably run indefinitely,
 		 * making DOSBox appear to hang.

diff --git a/src/gui/sdlmain.cpp b/src/gui/sdlmain.cpp
@@ -427,7 +427,7 @@ static Bitu Pause_Loop(void) {
 			}
 		}
 	}
-#ifdef EMTERPRETER_SYNC
+#if defined(EMTERPRETER_SYNC) || defined(EM_ASYNCIFY)
 	emscripten_sleep(10);
 #endif
 	return 0;
@@ -2027,7 +2027,7 @@ static void GUI_StartUp(Section * sec) {
  * The splash screen requires emterpreter sync.
  * Creating a 2D context prevents subsequent creation of a 3D context.
  */
-#if !defined(EMSCRIPTEN) || defined(EMTERPRETER_SYNC)
+#if !defined(EMSCRIPTEN) || defined(EMTERPRETER_SYNC) || defined(EM_ASYNCIFY)
 /* Please leave the Splash screen stuff in working order in DOSBox. We spend a lot of time making DOSBox. */
 	SDL_Surface* splash_surf = NULL;
 #ifdef EMSCRIPTEN
@@ -2080,8 +2080,12 @@ static void GUI_StartUp(Section * sec) {
 				}
 			}
 			if (exit_splash) break;
-#if defined(EMSCRIPTEN) && defined(EMTERPRETER_SYNC)
+#ifdef EMSCRIPTEN
+#ifdef EMTERPRETER_SYNC
 			emscripten_sleep_with_yield(1);
+#elif defined(EM_ASYNCIFY)
+			emscripten_sleep(1);
+#endif
 #endif
 
 			if (ct<1) {
@@ -2136,7 +2140,7 @@ static void GUI_StartUp(Section * sec) {
 		delete [] tmpbufp;
 
 	}
-#endif // !defined(EMSCRIPTEN) || defined(EMTERPRETER_SYNC)
+#endif // !defined(EMSCRIPTEN) || defined(EMTERPRETER_SYNC) || defined(EM_ASYNCIFY)
 	/* Get some Event handlers */
 	MAPPER_AddHandler(KillSwitch,MK_f9,MMOD1,"shutdown","ShutDown");
 	MAPPER_AddHandler(CaptureMouse,MK_f10,MMOD1,"capmouse","Cap Mouse");

diff --git a/src/shell/shell_misc.cpp b/src/shell/shell_misc.cpp
@@ -40,7 +40,7 @@ static void outc(Bit8u c) {
 }
 
 void DOS_Shell::InputCommand(char * line) {
-#if defined(EMSCRIPTEN) && !defined(EMTERPRETER_SYNC)
+#if defined(EMSCRIPTEN) && !defined(EMTERPRETER_SYNC) && !defined(EM_ASYNCIFY)
 	if (!strcmp(Files[input_handle]->name, "CON")) {
 		// This can be called during startup, before main loop being used.
 		LOG_MSG("Emulation ended because interactive shell is not supported.");