diff --git a/ueforth/Makefile b/ueforth/Makefile
index 877a68c..ea7b164 100644
--- a/ueforth/Makefile
+++ b/ueforth/Makefile
@@ -7,17 +7,22 @@ WINDOWS = $(OUT)/windows
 ARDUINO = $(OUT)/arduino
 DEPLOY = $(OUT)/deploy
 
-CFLAGS = -Wall -Werror \
-         -O2 \
-         -fno-exceptions \
-         -s \
-         -fomit-frame-pointer \
-         -fno-stack-protector \
-         -fno-ident -Wl,--build-id=none \
-         -ffunction-sections -fdata-sections \
-         -Wl,--gc-sections \
-         -fmerge-all-constants \
-         -I ./ -I $(OUT)
+CFLAGS_COMMON = -Wall -Werror \
+                -O2 \
+                -s \
+                -ffreestanding \
+                -fno-exceptions \
+                -fno-stack-check \
+                -fno-stack-protector \
+                -fno-stack-protector \
+                -fomit-frame-pointer \
+                -mno-stack-arg-probe \
+                -fno-ident -Wl,--build-id=none \
+                -ffunction-sections -fdata-sections \
+                -fmerge-all-constants \
+                -I ./ -I $(OUT)
+CFLAGS = $(CFLAGS_COMMON) \
+         -Wl,--gc-sections
 STRIP_ARGS = -S \
              --strip-unneeded \
              --remove-section=.note.gnu.gold-version \
@@ -27,9 +32,9 @@ STRIP_ARGS = -S \
              --remove-section=.note.ABI-tag
 LIBS=-ldl
 
-WINFLAGS = -ffreestanding -fno-stack-check \
-           -fno-stack-protector -mno-stack-arg-probe \
-           -mwindows -lkernel32
+WIN_CFLAGS = $(CFLAGS_COMMON) -mwindows -nostdlib \
+
+WIN_LIBS = -lkernel32
 
 # Default to 32-bit Windows for maximum portability.
 ifeq ($(WIN_ARCH),)
@@ -43,14 +48,23 @@ TARGETS = $(WEB)/terminal.html \
           $(ARDUINO)/ueforth/ueforth.ino
 
 # Selectively enable windows if tools available
-ifneq (, $(shell which $(WIN_ARCH)-w64-mingw32-windres))
-  ifneq (, $(shell which $(WIN_ARCH)-w64-mingw32-gcc))
-    TARGETS += $(WINDOWS)/uEforth.exe
+ifneq (, $(shell which i686-w64-mingw32-windres))
+  ifneq (, $(shell which i686-w64-mingw32-gcc))
+    TARGETS += $(WINDOWS)/uEforth32.exe
   else
-    $(warning "Missing $(WIN_ARCH)-w64-mingw32-gcc skipping Windows.")
+    $(warning "Missing i686-w64-mingw32-gcc skipping 32-bit Windows.")
   endif
 else
-  $(warning "Missing $(WIN_ARCH)-w64-mingw32-windres skipping Windows.")
+  $(warning "Missing i686-w64-mingw32-windres skipping 32-bit Windows.")
+endif
+ifneq (, $(shell which x86_64-w64-mingw32-windres))
+  ifneq (, $(shell which x86_64-w64-mingw32-gcc))
+    TARGETS += $(WINDOWS)/uEforth64.exe
+  else
+    $(warning "Missing i686-w64-mingw32-gcc skipping 64-bit Windows.")
+  endif
+else
+  $(warning "Missing i686-w64-mingw32-windres skipping 64-bit Windows.")
 endif
 
 all: $(TARGETS) tests $(DEPLOY)/app.yaml
@@ -124,10 +138,11 @@ ICON_SIZES = $(RES)/eforth256x256.png \
 $(RES)/eforth.ico: $(ICON_SIZES)
 	convert $^ $< $@
 
-WINDOWS_RESOURCES = $(RES)/ueforth_res.o
+$(RES)/ueforth_res32.o: windows/ueforth.rc $(RES)/eforth.ico
+	i686-w64-mingw32-windres $< $@
 
-$(WINDOWS_RESOURCES): windows/ueforth.rc $(RES)/eforth.ico
-	$(WIN_ARCH)-w64-mingw32-windres $< $@
+$(RES)/ueforth_res64.o: windows/ueforth.rc $(RES)/eforth.ico
+	x86_64-w64-mingw32-windres $< $@
 
 # ---- WEB ----
 
@@ -163,14 +178,23 @@ $(POSIX)/ueforth: \
 $(WINDOWS):
 	mkdir -p $@
 
-$(WINDOWS)/uEforth.exe: \
+$(WINDOWS)/uEforth32.exe: \
     windows/windows_main.c \
     common/opcodes.h \
     common/core.h \
     $(GEN)/windows_boot.h \
-    $(WINDOWS_RESOURCES) | $(WINDOWS)
-	$(WIN_ARCH)-w64-mingw32-gcc \
-    $(CFLAGS) $(WINFLAGS) $< $(WINDOWS_RESOURCES) -o $@
+    $(RES)/ueforth_res32.o | $(WINDOWS)
+	i686-w64-mingw32-gcc \
+    $(WIN_CFLAGS) $< $(RES)/ueforth_res32.o -o $@ $(WIN_LIBS)
+
+$(WINDOWS)/uEforth64.exe: \
+    windows/windows_main.c \
+    common/opcodes.h \
+    common/core.h \
+    $(GEN)/windows_boot.h \
+    $(RES)/ueforth_res64.o | $(WINDOWS)
+	x86_64-w64-mingw32-gcc \
+    $(WIN_CFLAGS) $< $(RES)/ueforth_res64.o -o $@ $(WIN_LIBS)
 
 # ---- ARDUINO ----
 
@@ -203,7 +227,8 @@ $(DEPLOY)/app.yaml: $(ARDUINO)/ueforth-arduino-esp32.zip \
 	mkdir -p $(DEPLOY)/static
 	cp -r $(ARDUINO)/ueforth-arduino-esp32.zip $(DEPLOY)/static
 	cp -r $(POSIX)/ueforth $(DEPLOY)/static/ueforth.linux
-	cp -r $(WINDOWS)/uEforth.exe $(DEPLOY)/static/uEforth.exe
+	cp -r $(WINDOWS)/uEforth32.exe $(DEPLOY)/static/uEforth32.exe
+	cp -r $(WINDOWS)/uEforth64.exe $(DEPLOY)/static/uEforth64.exe
 	cp -r $(RES)/eforth.ico $(DEPLOY)/static/favicon.ico
 	cp -r site/* $(DEPLOY)
 	cp -r site/.gcloudignore $(DEPLOY)
diff --git a/ueforth/common/opcodes.h b/ueforth/common/opcodes.h
index 2afe2e2..c611d8e 100644
--- a/ueforth/common/opcodes.h
+++ b/ueforth/common/opcodes.h
@@ -19,20 +19,22 @@ typedef uint64_t udcell_t;
 #define COMMA(n) *g_sys.heap++ = (n)
 #define IMMEDIATE() g_sys.last[-1] |= 1
 #define DOES(ip) *g_sys.last = (cell_t) && OP_DODOES; g_sys.last[1] = (cell_t) ip
-#define UMSMOD udcell_t ud = *(udcell_t *) &sp[-1]; \
-               --sp; *sp = (cell_t) (ud % tos); \
-               tos = (cell_t) (ud / tos)
-#define SSMOD dcell_t d = (dcell_t) *sp * (dcell_t) sp[-1]; \
-              --sp; *sp = (cell_t) (((udcell_t) d) % tos); \
-              tos = (cell_t) (d < 0 ? ~(~d / tos) : d / tos)
+#ifndef UMSMOD_FUNC
+#define UMSMOD_FUNC udcell_t ud = *(udcell_t *) &sp[-1]; \
+                    --sp; *sp = (cell_t) (ud % tos); \
+                    tos = (cell_t) (ud / tos)
+#define SSMOD_FUNC dcell_t d = (dcell_t) *sp * (dcell_t) sp[-1]; \
+                   --sp; *sp = (cell_t) (((udcell_t) d) % tos); \
+                   tos = (cell_t) (d < 0 ? ~(~d / tos) : d / tos)
+#endif
 #define PARK DUP; g_sys.ip = ip; g_sys.rp = rp; g_sys.sp = sp
 
 #define OPCODE_LIST \
   X("0=", ZEQUAL, tos = !tos ? -1 : 0) \
   X("0<", ZLESS, tos = (tos|0) < 0 ? -1 : 0) \
   X("+", PLUS, tos = (tos + *sp) | 0; --sp) \
-  X("UM/MOD", UMSMOD, UMSMOD) \
-  X("*/MOD", SSMOD, SSMOD) \
+  X("UM/MOD", UMSMOD, UMSMOD_FUNC) \
+  X("*/MOD", SSMOD, SSMOD_FUNC) \
   X("AND", AND, tos = tos & *sp; --sp) \
   X("OR", OR, tos = tos | *sp; --sp) \
   X("XOR", XOR, tos = tos ^ *sp; --sp) \
diff --git a/ueforth/site/index.html b/ueforth/site/index.html
index d055619..486f88c 100644
--- a/ueforth/site/index.html
+++ b/ueforth/site/index.html
@@ -17,10 +17,11 @@ In its original form metacompilation is avoided.
 <p>
 Version of uEforth - A reduced cross-platform EForth version (RECOMMENDED)
 <ul>
-  <li><a href="static/uEforth.exe">uEforth.exe</a> - Window EXE uEforth</li>
-  <li><a href="static/ueforth.linux">ueforth.linux</a> - Linux Executable uEforth</li>
   <li><a href="static/ueforth-arduino-esp32.zip">ueforth-arduino-esp32.zip</a>
      - Arudino Source Code</li>
+  <li><a href="static/uEforth32.exe">uEforth32.exe</a> - Window 32-bit EXE uEforth</li>
+  <li><a href="static/uEforth64.exe">uEforth64.exe</a> - Window 64-bit EXE uEforth</li>
+  <li><a href="static/ueforth.linux">ueforth.linux</a> - Linux 64-bit Executable uEforth</li>
   <li><a href="https://github.com/flagxor/eforth" target="_blank">http://github.com/flagxor/eforth</a>
      - Complete Source Code (under ueforth)</li>
 </ul>
diff --git a/ueforth/web/dump_web_opcodes.c b/ueforth/web/dump_web_opcodes.c
index ecfe6fd..3c82eca 100644
--- a/ueforth/web/dump_web_opcodes.c
+++ b/ueforth/web/dump_web_opcodes.c
@@ -31,4 +31,5 @@ int main(int argc, char *argv[]) {
     fprintf(stderr, "USAGE: %s cases/dict\n", argv[1]);
     return 1;
   }
+  return 0;
 }
diff --git a/ueforth/windows/windows_main.c b/ueforth/windows/windows_main.c
index bd4e75c..eb3b844 100644
--- a/ueforth/windows/windows_main.c
+++ b/ueforth/windows/windows_main.c
@@ -2,6 +2,17 @@
 
 #define CALLTYPE WINAPI
 
+# define UMSMOD_FUNC \
+  asm("div %2" \
+      : "=a" (tos), "=d" (sp[-1]) \
+      : "r" (tos), "a" (sp[-1]), "d" (*sp)); --sp
+
+# define SSMOD_FUNC \
+  w = tos; asm("imul %4\n\t" \
+      "idiv %2" \
+      : "=a" (tos), "=d" (sp[-1]) \
+      : "r" (w), "a" (sp[-1]), "d" (*sp)); --sp; if (*sp < 0) { *sp += w; --tos; }
+
 #include "common/opcodes.h"
 #include "common/calling.h"
 
@@ -19,8 +30,7 @@
 
 #include "gen/windows_boot.h"
 
-int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrev,
-                   PSTR pCmdLine, int nCmdShow) {
+int WINAPI WinMainCRTStartup(void) {
   void *heap = VirtualAlloc(
       NULL, HEAP_SIZE, MEM_RESERVE | MEM_COMMIT, PAGE_EXECUTE_READWRITE);
   ueforth(0, 0, heap, boot, sizeof(boot));