diff --git a/ueforth/Makefile b/ueforth/Makefile
index fb985f2..cc654fa 100644
--- a/ueforth/Makefile
+++ b/ueforth/Makefile
@@ -74,7 +74,8 @@ WIN_LFLAGS64 = /LIBPATH:"c:/Program Files (x86)/Microsoft SDKs/Windows/v7.1A/Lib
 TARGETS = $(WEB)/terminal.html \
           $(WEB)/ueforth.js \
           $(POSIX)/ueforth \
-          $(ESP32)/ESP32forth/ESP32forth.ino
+          $(ESP32)/ESP32forth/ESP32forth.ino \
+          $(ESP32_SIM)/Esp32forth-sim
 
 LSQ = ls 2>/dev/null
 
@@ -260,6 +261,7 @@ $(POSIX)/ueforth: \
     posix/main.c \
     common/opcodes.h \
     common/calls.h \
+    common/calling.h \
     common/floats.h \
     common/interp.h \
     common/core.h \
@@ -276,6 +278,7 @@ $(WINDOWS)/uEf32.obj: \
     windows/main.c \
     common/opcodes.h \
     common/calls.h \
+    common/calling.h \
     common/floats.h \
     common/core.h \
     windows/interp.h \
@@ -291,6 +294,7 @@ $(WINDOWS)/uEf64.obj: \
     windows/main.c \
     common/opcodes.h \
     common/calls.h \
+    common/calling.h \
     common/floats.h \
     common/core.h \
     windows/interp.h \
@@ -307,12 +311,26 @@ $(WINDOWS)/uEf64.exe: \
 $(ESP32_SIM):
 	mkdir -p $@
 
-$(ESP32_SIM)/print-builtins: \
-    esp32/print-builtins.c esp32/builtins.h | $(ESP32_SIM)
+$(GEN)/print-esp32-builtins: \
+    esp32/print-builtins.c esp32/builtins.h | $(GEN)
 	$(CC) $< -o $@
 
-print: $(ESP32_SIM)/print-builtins
-	$<
+$(GEN)/esp32_sim_opcodes.h: $(GEN)/print-esp32-builtins | $(GEN)
+	$< >$@
+
+$(ESP32_SIM)/Esp32forth-sim: \
+    esp32/sim_main.cpp \
+    esp32/main.cpp \
+    common/opcodes.h \
+    common/floats.h \
+    common/calling.h \
+    common/floats.h \
+    common/core.h \
+    common/interp.h \
+    $(GEN)/esp32_boot.h \
+    $(GEN)/esp32_sim_opcodes.h | $(ESP32_SIM)
+	$(CXX) $(CFLAGS) -g $< -o $@
+	strip $(STRIP_ARGS) $@
 
 # ---- ESP32 ----
 
@@ -329,12 +347,14 @@ ESP32_PARTS = common/replace.js \
               esp32/options.h \
               esp32/builtins.h \
               esp32/builtins.cpp \
+              esp32/main.cpp \
               $(GEN)/esp32_boot.h
 
 $(ESP32)/ESP32forth/ESP32forth.ino: $(ESP32_PARTS) | $(ESP32)/ESP32forth
 	cat esp32/template.ino | common/replace.js \
      VERSION=$(VERSION) \
      REVISION=$(REVISION) \
+     config=@esp32/config.h \
      opcodes=@common/opcodes.h \
      calling=@common/calling.h \
      floats=@common/floats.h \
@@ -343,6 +363,7 @@ $(ESP32)/ESP32forth/ESP32forth.ino: $(ESP32_PARTS) | $(ESP32)/ESP32forth
      options=@esp32/options.h \
      builtins.h=@esp32/builtins.h \
      builtins.cpp=@esp32/builtins.cpp \
+     main.cpp=@esp32/main.cpp \
      boot=@$(GEN)/esp32_boot.h \
      >$@
 
diff --git a/ueforth/esp32/builtins.cpp b/ueforth/esp32/builtins.cpp
index 5bff541..3b023c1 100644
--- a/ueforth/esp32/builtins.cpp
+++ b/ueforth/esp32/builtins.cpp
@@ -117,12 +117,3 @@ static cell_t TimerIsrRegister(cell_t group, cell_t timer, cell_t xt, cell_t arg
   return timer_isr_register((timer_group_t) group, (timer_idx_t) timer, HandleInterrupt, args, flags, (timer_isr_handle_t *) ret);
 }
 #endif
-
-void setup() {
-  cell_t *heap = (cell_t *) malloc(HEAP_SIZE);
-  forth_init(0, 0, heap, boot, sizeof(boot));
-}
-
-void loop() {
-  g_sys.rp = forth_run(g_sys.rp);
-}
diff --git a/ueforth/esp32/builtins.h b/ueforth/esp32/builtins.h
index 93a576e..a59bf2c 100644
--- a/ueforth/esp32/builtins.h
+++ b/ueforth/esp32/builtins.h
@@ -14,27 +14,23 @@
 
 #ifndef SIM_PRINT_ONLY
 
-#ifdef ENABLE_WEBSERVER_SUPPORT
-# include "WebServer.h"
-#endif
+# ifdef ENABLE_WEBSERVER_SUPPORT
+#  include "WebServer.h"
+# endif
 
-#include <errno.h>
-#include <unistd.h>
-#include <fcntl.h>
-#include <sys/types.h>
-#include <sys/stat.h>
-#include <sys/select.h>
-
-#define HEAP_SIZE (100 * 1024)
-#define STACK_CELLS 512
-#define INTERRUPT_STACK_CELLS 64
+# include <errno.h>
+# include <unistd.h>
+# include <fcntl.h>
+# include <sys/types.h>
+# include <sys/stat.h>
+# include <sys/select.h>
 
 // Optional hook to pull in words for userwords.h
-#if __has_include("userwords.h")
-# include "userwords.h"
-#else
-# define USER_WORDS
-#endif
+# if __has_include("userwords.h")
+#  include "userwords.h"
+# else
+#  define USER_WORDS
+# endif
 
 static cell_t ResizeFile(cell_t fd, cell_t size);
 
diff --git a/ueforth/esp32/config.h b/ueforth/esp32/config.h
new file mode 100644
index 0000000..4ea139b
--- /dev/null
+++ b/ueforth/esp32/config.h
@@ -0,0 +1,17 @@
+// Copyright 2022 Bradley D. Nelson
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#define HEAP_SIZE (100 * 1024)
+#define STACK_CELLS 512
+#define INTERRUPT_STACK_CELLS 64
diff --git a/ueforth/esp32/main.cpp b/ueforth/esp32/main.cpp
new file mode 100644
index 0000000..c981c25
--- /dev/null
+++ b/ueforth/esp32/main.cpp
@@ -0,0 +1,22 @@
+// Copyright 2022 Bradley D. Nelson
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+void setup() {
+  cell_t *heap = (cell_t *) malloc(HEAP_SIZE);
+  forth_init(0, 0, heap, boot, sizeof(boot));
+}
+
+void loop() {
+  g_sys.rp = forth_run(g_sys.rp);
+}
diff --git a/ueforth/esp32/print-builtins.c b/ueforth/esp32/print-builtins.c
index 2e46477..79aeae4 100644
--- a/ueforth/esp32/print-builtins.c
+++ b/ueforth/esp32/print-builtins.c
@@ -43,8 +43,10 @@
 #define Y(name, code) X(#name, name, code)
 
 int main() {
-#define X(str, name, code) printf("%s\n", str);
+  printf("#define PLATFORM_OPCODE_LIST \\\n");
+#define X(str, name, code) printf("  X(\"%s\", %s, ) \\\n", str, #name);
   PLATFORM_OPCODE_LIST
 #undef X
+  printf("\n");
   return 0;
 }
diff --git a/ueforth/esp32/sim_main.cpp b/ueforth/esp32/sim_main.cpp
new file mode 100644
index 0000000..e21a7b9
--- /dev/null
+++ b/ueforth/esp32/sim_main.cpp
@@ -0,0 +1,31 @@
+// Copyright 2022 Bradley D. Nelson
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "esp32/config.h"
+#include "esp32/options.h"
+#include "common/opcodes.h"
+#include "common/floats.h"
+#include "common/calling.h"
+#include "gen/esp32_sim_opcodes.h"
+#include "common/core.h"
+#include "common/interp.h"
+#include "gen/esp32_boot.h"
+#include "esp32/main.cpp"
+
+int main(int argc, char *argv[]) {
+  setup();
+  for (;;) {
+    loop();
+  }
+}
diff --git a/ueforth/esp32/template.ino b/ueforth/esp32/template.ino
index 87c2879..f9e3a7d 100644
--- a/ueforth/esp32/template.ino
+++ b/ueforth/esp32/template.ino
@@ -19,9 +19,11 @@
  * Revision: {{REVISION}}
  */
 
+{{config}}
+{{options}}
 {{opcodes}}
 {{floats}}
 {{calling}}
-{{options}}
 {{builtins.h}}
 {{builtins.cpp}}
+{{main.cpp}}