Merge pull request #385 from ChinYikMing/emcc-port-video-games

Enable run video games using WebAssembly

Makefile

@@ -193,17 +193,31 @@ OBJS := \
 OBJS := $(addprefix $(OUT)/, $(OBJS))
 deps := $(OBJS:%.o=%.o.d)
 
-EXPORTED_FUNCS := _main
+include mk/external.mk
+
+deps_emcc :=
+ASSETS := assets
+WEB_JS_RESOURCES := $(ASSETS)/js
+EXPORTED_FUNCS := _main,_indirect_rv_halt
 ifeq ("$(CC_IS_EMCC)", "1")
 CFLAGS_emcc += -sINITIAL_MEMORY=2GB \
 	       -sALLOW_MEMORY_GROWTH \
 	       -s"EXPORTED_FUNCTIONS=$(EXPORTED_FUNCS)" \
-	       --embed-file build \
+	       -sSTACK_SIZE=4MB \
+	       -sPTHREAD_POOL_SIZE=navigator.hardwareConcurrency \
+	       --embed-file build@/ \
+	       --embed-file build/timidity@/etc/timidity \
 	       -DMEM_SIZE=0x40000000 \
+	       -DCYCLE_PER_STEP=2000000 \
+	       --pre-js $(WEB_JS_RESOURCES)/pre.js \
+	       -O3 \
 	       -w
+
+# used to download all dependencies of elf executable and bundle into single wasm
+deps_emcc += $(DOOM_DATA) $(QUAKE_DATA) $(TIMIDITY_DATA)
 endif
 
-$(OUT)/%.o: src/%.c
+$(OUT)/%.o: src/%.c $(deps_emcc)
 	$(VECHO) "  CC\t$@\n"
 	$(Q)$(CC) -o $@ $(CFLAGS) $(CFLAGS_emcc) -c -MMD -MF $@.d $<
 
@@ -259,22 +273,36 @@ misalign: $(BIN)
 	    $(PRINTF) "Failed.\n"; \
 	    fi
 
-include mk/external.mk
-
 # Non-trivial demonstration programs
 ifeq ($(call has, SDL), 1)
-doom: $(BIN) $(DOOM_DATA)
-	(cd $(OUT); ../$(BIN) doom.elf)
+doom_action := (cd $(OUT); ../$(BIN) doom.elf)
+ifeq ("$(CC_IS_EMCC)", "1")
+# TODO: check Chrome or Firefox is available and serve python httpd and open the web page
+# TODO: serve and open a web page, show warning if environment not support pthread runtime
+doom_action :=
+endif
+doom_deps += $(DOOM_DATA) $(BIN)
+doom: $(doom_deps)
+	$(doom_action)
+
 ifeq ($(call has, EXT_F), 1)
-quake: $(BIN) $(QUAKE_DATA)
-	(cd $(OUT); ../$(BIN) quake.elf)
+quake_action := (cd $(OUT); ../$(BIN) quake.elf)
+ifeq ("$(CC_IS_EMCC)", "1")
+# TODO: check Chrome or Firefox is available and serve python httpd and open the web page
+# TODO: serve and open a web page, show warning if environment not support pthread runtime
+quake_action :=
+endif
+quake_deps += $(QUAKE_DATA) $(BIN)
+quake: $(quake_deps)
+	$(quake_action)
 endif
 endif
 
 clean:
 	$(RM) $(BIN) $(OBJS) $(HIST_BIN) $(HIST_OBJS) $(deps) $(WEB_FILES) $(CACHE_OUT) src/rv32_jit.c
 distclean: clean
 	-$(RM) $(DOOM_DATA) $(QUAKE_DATA)
+	$(RM) -r $(TIMIDITY_DATA)
 	$(RM) -r $(OUT)/id1
 	$(RM) *.zip
 	$(RM) -r $(OUT)/mini-gdbstub

assets/js/pre.js

@@ -0,0 +1,9 @@
+Module['noInitialRun'] = true;
+Module['onRuntimeInitialized'] = function(target_elf) {
+    if(target_elf === undefined){
+      console.warn("target elf executable is undefined");
+      return;
+    }
+
+    callMain([target_elf]);
+};

mk/external.mk

@@ -2,26 +2,40 @@
 #   _DATA_URL : the hyperlink which points to archive.
 #   _DATA : the file to be read by specific executable.
 #   _DATA_SHA1 : the checksum of the content in _DATA
+#   _DATA_EXTRACT : the way to extract content from compressed file
+#   _DATA_VERIFY : the way to verify the checksum of extracted file
 
 # Doom
 # https://tipsmake.com/how-to-run-doom-on-raspberry-pi-without-emulator
 DOOM_DATA_URL = http://www.doomworld.com/3ddownloads/ports/shareware_doom_iwad.zip
 DOOM_DATA = $(OUT)/DOOM1.WAD
 DOOM_DATA_SHA1 = 5b2e249b9c5133ec987b3ea77596381dc0d6bc1d
+DOOM_DATA_EXTRACT = unzip -d $(OUT) $(notdir $($(T)_DATA_URL))
+DOOM_DATA_VERIFY = echo "$(strip $$($(T)_DATA_SHA1))  $$@" | $(SHA1SUM) -c
 
 # Quake
 QUAKE_DATA_URL = https://www.libsdl.org/projects/quake/data/quakesw-1.0.6.zip
 QUAKE_DATA = $(OUT)/id1/pak0.pak
 QUAKE_DATA_SHA1 = 36b42dc7b6313fd9cabc0be8b9e9864840929735
+QUAKE_DATA_EXTRACT = unzip -d $(OUT) $(notdir $($(T)_DATA_URL))
+QUAKE_DATA_VERIFY = echo "$(strip $$($(T)_DATA_SHA1))  $$@" | $(SHA1SUM) -c
+
+# Timidity software synthesizer configuration for SDL2_mixer
+TIMIDITY_DATA_URL = http://www.libsdl.org/projects/mixer/timidity/timidity.tar.gz
+TIMIDITY_DATA = $(OUT)/timidity
+TIMIDITY_DATA_SHA1 = cdd30736508d26968222a6414f3beabc3b7a0725
+TIMIDITY_DATA_EXTRACT = tar -xf $(notdir $($(T)_DATA_URL)) -C $(OUT)
+TIMIDITY_TMP_FILE = /tmp/timidity_sha1.txt
+TIMIDITY_DATA_VERIFY = echo "$(TIMIDITY_DATA_SHA1)" > $(TIMIDITY_TMP_FILE) | find $(TIMIDITY_DATA) -type f -print0 | sort -z | xargs -0 shasum | shasum | cut -f 1 -d ' '
 
 define download-n-extract
 $($(T)_DATA):
 	$(VECHO) "  GET\t$$@\n"
 	$(Q)curl --progress-bar -O -L -C - "$(strip $($(T)_DATA_URL))"
-	$(Q)unzip -d $(OUT) $(notdir $($(T)_DATA_URL))
-	$(Q)echo "$(strip $$($(T)_DATA_SHA1))  $$@" | $(SHA1SUM) -c
-	$(Q)$(RM) $(notdir $($(T)_DATA_URL))
+	$(Q)$($(T)_DATA_EXTRACT)
+	$(Q)$($(T)_DATA_VERIFY)
+	$(Q)$(RM) $(notdir $($(T)_DATA_URL)) $($(T)_TMP_FILE)
 endef
 
-EXTERNAL_DATA = DOOM QUAKE
-$(foreach T,$(EXTERNAL_DATA),$(eval $(download-n-extract))) 
+EXTERNAL_DATA = DOOM QUAKE TIMIDITY
+$(foreach T,$(EXTERNAL_DATA),$(eval $(download-n-extract)))

mk/toolchain.mk

@@ -4,15 +4,35 @@ CC_IS_GCC :=
 ifneq ($(shell $(CC) --version | head -n 1 | grep emcc),)
     CC_IS_EMCC := 1
 
+    EMCC_VERSION := $(shell $(CC) --version | head -n 1 | cut -f10 -d ' ')
+    EMCC_MAJOR := $(shell echo $(EMCC_VERSION) | cut -f1 -d.)
+    EMCC_MINOR := $(shell echo $(EMCC_VERSION) | cut -f2 -d.)
+    EMCC_PATCH := $(shell echo $(EMCC_VERSION) | cut -f3 -d.)
+
+    # When the emcc version is not 3.1.51, the latest SDL2_mixer library is fetched by emcc and music might not be played in the web browser
+    SDL_MUSIC_PLAY_AT_EMCC_MAJOR := 3
+    SDL_MUSIC_PLAY_AT_EMCC_MINOR := 1
+    SDL_MUSIC_PLAY_AT_EMCC_PATCH := 51
+    SDL_MUSIC_CANNOT_PLAY_WARNING := Video games music might not be played. You may switch emcc to version $(SDL_MUSIC_PLAY_AT_EMCC_MAJOR).$(SDL_MUSIC_PLAY_AT_EMCC_MINOR).$(SDL_MUSIC_PLAY_AT_EMCC_PATCH)
+    ifeq ($(shell echo $(EMCC_MAJOR)\==$(SDL_MUSIC_PLAY_AT_EMCC_MAJOR) | bc), 1)
+        ifeq ($(shell echo $(EMCC_MINOR)\==$(SDL_MUSIC_PLAY_AT_EMCC_MINOR) | bc), 1)
+            ifeq ($(shell echo $(EMCC_PATCH)\==$(SDL_MUSIC_PLAY_AT_EMCC_PATCH) | bc), 1)
+	        # do nothing
+            else
+                $(warning $(SDL_MUSIC_CANNOT_PLAY_WARNING))
+            endif
+        else
+	    $(warning $(SDL_MUSIC_CANNOT_PLAY_WARNING))
+        endif
+    else
+	$(warning $(SDL_MUSIC_CANNOT_PLAY_WARNING))
+    endif
+
     # see commit 165c1a3 of emscripten
     MIMALLOC_SUPPORT_SINCE_MAJOR := 3
     MIMALLOC_SUPPORT_SINCE_MINOR := 1
     MIMALLOC_SUPPORT_SINCE_PATCH := 50
     MIMALLOC_UNSUPPORTED_WARNING := mimalloc is supported after version $(MIMALLOC_SUPPORT_SINCE_MAJOR).$(MIMALLOC_SUPPORT_SINCE_MINOR).$(MIMALLOC_SUPPORT_SINCE_PATCH)
-    EMCC_VERSION := $(shell $(CC) --version | head -n 1 | cut -f10 -d ' ')
-    EMCC_MAJOR := $(shell echo $(EMCC_VERSION) | cut -f1 -d.)
-    EMCC_MINOR := $(shell echo $(EMCC_VERSION) | cut -f2 -d.)
-    EMCC_PATCH := $(shell echo $(EMCC_VERSION) | cut -f3 -d.)
     ifeq ($(shell echo $(EMCC_MAJOR)\>=$(MIMALLOC_SUPPORT_SINCE_MAJOR) | bc), 1)
         ifeq ($(shell echo $(EMCC_MINOR)\>=$(MIMALLOC_SUPPORT_SINCE_MINOR) | bc), 1)
             ifeq ($(shell echo $(EMCC_PATCH)\>=$(MIMALLOC_SUPPORT_SINCE_PATCH) | bc), 1)

src/emulate.c

@@ -10,6 +10,10 @@
 #include <stdlib.h>
 #include <string.h>
 
+#ifdef __EMSCRIPTEN__
+#include <emscripten.h>
+#endif
+
 #if RV32_HAS(EXT_F)
 #include <math.h>
 #include "softfloat.h"
@@ -1074,9 +1078,11 @@ static bool runtime_profiler(riscv_t *rv, block_t *block)
 typedef void (*exec_block_func_t)(riscv_t *rv, uintptr_t);
 #endif
 
-void rv_step(riscv_t *rv)
+void rv_step(void *arg)
 {
-    assert(rv);
+    assert(arg);
+    riscv_t *rv = arg;
+
     vm_attr_t *attr = PRIV(rv);
     uint32_t cycles = attr->cycle_per_step;
 
@@ -1174,6 +1180,13 @@ void rv_step(riscv_t *rv)
 #endif
         prev = block;
     }
+
+#ifdef __EMSCRIPTEN__
+    if (rv_has_halted(rv)) {
+        emscripten_cancel_main_loop();
+        rv_delete(rv); /* clean up and reuse memory */
+    }
+#endif
 }
 
 void ebreak_handler(riscv_t *rv)

src/main.c

@@ -168,13 +168,31 @@ static void dump_test_signature(const char *prog_name)
     elf_delete(elf);
 }
 
+/* CYCLE_PER_STEP shall be defined on different runtime */
+#ifndef CYCLE_PER_STEP
+#define CYCLE_PER_STEP 100
+#endif
 /* MEM_SIZE shall be defined on different runtime */
 #ifndef MEM_SIZE
 #define MEM_SIZE 0xFFFFFFFFULL /* 2^32 - 1 */
 #endif
 #define STACK_SIZE 0x1000       /* 4096 */
 #define ARGS_OFFSET_SIZE 0x1000 /* 4096 */
 
+/* To use rv_halt function in wasm, we have to expose RISC-V instance(rv),
+ * but we can add a layer to not expose the instance and make rv_halt
+ * callable. A small trade-off is that declaring instance as a global
+ * variable. rv_halt is useful when cancelling the main loop of wasm,
+ * see rv_step in emulate.c for more detail
+ */
+riscv_t *rv;
+#ifdef __EMSCRIPTEN__
+void indirect_rv_halt()
+{
+    rv_halt(rv);
+}
+#endif
+
 int main(int argc, char **args)
 {
     if (argc == 1 || !parse_args(argc, args)) {
@@ -199,14 +217,14 @@ int main(int argc, char **args)
         .run_flag = run_flag,
         .profile_output_file = prof_out_file,
         .data.user = malloc(sizeof(vm_user_t)),
-        .cycle_per_step = 100,
+        .cycle_per_step = CYCLE_PER_STEP,
         .allow_misalign = opt_misaligned,
     };
     assert(attr.data.user);
     attr.data.user->elf_program = opt_prog_name;
 
     /* create the RISC-V runtime */
-    riscv_t *rv = rv_create(&attr);
+    rv = rv_create(&attr);
     if (!rv) {
         fprintf(stderr, "Unable to create riscv emulator\n");
         attr.exit_code = 1;

src/riscv.c

@@ -18,6 +18,10 @@
 #define STDERR_FILENO FILENO(stderr)
 #endif
 
+#ifdef __EMSCRIPTEN__
+#include <emscripten.h>
+#endif
+
 #include "elf.h"
 #include "mpool.h"
 #include "riscv.h"
@@ -315,9 +319,13 @@ void rv_run(riscv_t *rv)
         rv_debug(rv);
 #endif
     else {
+#ifdef __EMSCRIPTEN__
+        emscripten_set_main_loop_arg(rv_step, (void *) rv, 0, 1);
+#else
         /* default main loop */
         for (; !rv_has_halted(rv);) /* run until the flag is done */
             rv_step(rv);            /* step instructions */
+#endif
     }
 
     if (attr->run_flag & RV_RUN_PROFILE) {

src/riscv.h

@@ -166,7 +166,7 @@ void rv_debug(riscv_t *rv);
 #endif
 
 /* step the RISC-V emulator */
-void rv_step(riscv_t *rv);
+void rv_step(void *arg);
 
 /* set the program counter of a RISC-V emulator */
 bool rv_set_pc(riscv_t *rv, riscv_word_t pc);

src/syscall_sdl.c

@@ -708,6 +708,12 @@ static void play_sfx(riscv_t *rv)
         .volume = volume,
     };
     pthread_create(&sfx_thread, NULL, sfx_handler, &sfx);
+    /* FIXME: In web browser runtime, web workers in thread pool do not reap
+     * after sfx_handler return, thus we have to join them. sfx_handler does not
+     * contain infinite loop,so do not worry to be stalled by it */
+#ifdef __EMSCRIPTEN__
+    pthread_join(sfx_thread, NULL);
+#endif
 }
 
 static void play_music(riscv_t *rv)
@@ -738,6 +744,12 @@ static void play_music(riscv_t *rv)
         .volume = volume,
     };
     pthread_create(&music_thread, NULL, music_handler, &music);
+    /* FIXME: In web browser runtime, web workers in thread pool do not reap
+     * after music_handler return, thus we have to join them. music_handler does
+     * not contain infinite loop,so do not worry to be stalled by it */
+#ifdef __EMSCRIPTEN__
+    pthread_join(music_thread, NULL);
+#endif
 }
 
 static void stop_music(riscv_t *rv UNUSED)