Attempt at emscripten

.github/workflows/build.yml

@@ -23,7 +23,29 @@ jobs:
     # Steps represent a sequence of tasks that will be executed as part of the job
     steps:
       - uses: actions/checkout@v4
-      - name: Build
+      - name: Build C program
         working-directory: ${{ github.workspace }}/
         run: make
 
+
+  emscripten:
+    # The type of runner that the job will run on
+    runs-on: ubuntu-latest
+
+    # Steps represent a sequence of tasks that will be executed as part of the job
+    steps:
+      - name: Checkout binaries for web version
+        working-directory: ${{ github.workspace }}/
+        run: |
+         git clone --depth=1 https://github.com/misterblack1/plexus-p20.git
+         mv plexus-p20/ROMs/U17-MERGED.BIN plexus-p20/ROMs/U15-MERGED.BIN .
+         gunzip < plexus-p20/disk/plexus-sanitized.img.gz > plexus-sanitized.img
+      - name: Get emscripten
+        working-directory: ${{ github.workspace }}/
+        run: |
+         git clone --depth=1 https://github.com/emscripten-core/emsdk.git
+         cd emsdk; ./emsdk install latest; ./emsdk activate latest
+      - name: Compile for web
+        working-directory: ${{ github.workspace }}/
+        run: source ./emsdk/emsdk_env.sh; make plexem.mjs
+

.gitmodules

@@ -0,0 +1,3 @@
+[submodule "xterm-pty"]
+	path = xterm-pty
+	url = https://github.com/mame/xterm-pty.git

Makefile

@@ -15,6 +15,20 @@ Musashi/m68kops.h:
 emu: $(SRC:.c=.o)
 	$(CC) $(CFLAGS) -o $@  $^ -lm
 
+
+# Note that PROXY_TO_PTHREAD doesn't generally work as the needed
+# SharedArrayBuffer needs some pretty specific server settings.
+EMCC_ARGS = -s ASYNCIFY
+#EMCC_ARGS = -s PROXY_TO_PTHREAD -pthread
+EMCC_ARGS += --js-library xterm-pty/emscripten-pty.js
+EMCC_ARGS += --preload-file plexus-sanitized.img
+EMCC_ARGS += --preload-file U15-MERGED.BIN
+EMCC_ARGS += --preload-file U17-MERGED.BIN
+EMCC_ARGS += -O2 -gsource-map --source-map-base=./
+
+plexem.mjs: $(SRC)
+	emcc -o $@ $(EMCC_ARGS) $^ -lm 
+
 clean:
 	rm -f $(SRC:.c=.o) 
 	rm -f emu

emu.c

@@ -5,6 +5,11 @@
 #include <stdlib.h>
 #include <time.h>
 #include <signal.h>
+#include <sys/time.h>
+#include <unistd.h>
+#ifdef __EMSCRIPTEN__
+#include "emscripten.h"
+#endif
 #include "Musashi/m68k.h"
 #include "uart.h"
 #include "ramrom.h"
@@ -741,6 +746,9 @@ static void sig_hdl(int sig) {
 	m68k_modify_timeslice(0);
 }
 
+//if running realtime, we'll sleep for a bit every SLEEP_EVERY_US us
+#define SLEEP_EVERY_US 10000 //10ms = 100Hz
+
 void emu_start(emu_cfg_t *cfg) {
 	signal(SIGQUIT, sig_hdl); // ctrl+\ to dump status
 	tracefile=fopen("trace.txt","w");
@@ -784,6 +792,10 @@ void emu_start(emu_cfg_t *cfg) {
 	int cpu_in_reset[2]={0};
 	int cycles_remaining[2]={0};
 
+	struct timeval last_delay_at;
+	int emulated_us_since_last_delay=0;
+	gettimeofday(&last_delay_at, NULL);
+
 	while(1) {
 		for (int i=0; i<2; i++) {
 			m68k_set_context(cpuctx[i]);
@@ -824,6 +836,25 @@ void emu_start(emu_cfg_t *cfg) {
 				m68k_get_context(cpuctx[i]);
 			}
 		}
+		if (cfg->realtime) {
+			emulated_us_since_last_delay+=10;
+
+			struct timeval time_since_last_delay;
+			struct timeval now;
+			gettimeofday(&now, NULL);
+			timersub(&now, &last_delay_at, &time_since_last_delay);
+			if (time_since_last_delay.tv_sec!=0 || time_since_last_delay.tv_usec>=SLEEP_EVERY_US) {
+				int w=emulated_us_since_last_delay-time_since_last_delay.tv_usec;
+				if (w<1000) w=1000; //sleep at least a ms
+#ifdef __EMSCRIPTEN__
+				emscripten_sleep(w/1000);
+#else
+				usleep(w);
+#endif
+				gettimeofday(&last_delay_at, NULL);
+				emulated_us_since_last_delay=0;
+			}
+		}
 	}
 }
 

emu.h

@@ -28,6 +28,7 @@ typedef struct {
 	const char *u17_rom;
 	const char *hd0img;
 	const char *rtcram;
+	int realtime;
 } emu_cfg_t;
 
 void emu_start(emu_cfg_t *cfg);

main.c

@@ -60,8 +60,14 @@ int main(int argc, char **argv) {
 	static_assert(sizeof(level_str)/sizeof(level_str[0])==LOG_LVL_MAX,
 					"level_str array out of sync");
 	emu_cfg_t cfg={
+#ifdef __EMSCRIPTEN__
+		.u15_rom="U15-MERGED.BIN",
+		.u17_rom="U17-MERGED.BIN",
+		.realtime=1,
+#else
 		.u15_rom="../plexus-p20/ROMs/U15-MERGED.BIN",
 		.u17_rom="../plexus-p20/ROMs/U17-MERGED.BIN",
+#endif
 		.hd0img="plexus-sanitized.img",
 		.rtcram="rtcram.bin"
 	};
@@ -73,6 +79,8 @@ int main(int argc, char **argv) {
 		} else if (strcmp(argv[i], "-u17")==0 && i+1<argc) {
 			i++;
 			cfg.u15_rom=argv[i];
+		} else if (strcmp(argv[i], "-r")==0) {
+			cfg.realtime=1;
 		} else if (strcmp(argv[i], "-l")==0 && i+1<argc) {
 			i++;
 			error|=parse_loglvl_str(argv[i]);
@@ -87,6 +95,7 @@ int main(int argc, char **argv) {
 		printf("Usage: %s [args]\n", argv[0]);
 		printf(" -u15 Path to U15 rom file\n");
 		printf(" -u17 Path to U17 rom file\n");
+		printf(" -r Try to run at realtime speeds\n");
 		printf(" -l module=level - set logging level of module to specified level\n");
 		printf(" -l level - Set overal log level to specified level\n");
 		printf("Modules: ");