diff --git a/vm/nga-c/retro.c b/vm/nga-c/retro.c
index ed85655..11a12d1 100644
--- a/vm/nga-c/retro.c
+++ b/vm/nga-c/retro.c
@@ -29,6 +29,8 @@
 #include "config.h"
 #include "devices.h"
 
+#include "utf32.c"
+
 #define ACTIVE vm->cpu[vm->active]
 #define TIB vm->memory[7]
 #define TIB_END vm->memory[8]
diff --git a/vm/nga-c/utf32.c b/vm/nga-c/utf32.c
new file mode 100644
index 0000000..0571401
--- /dev/null
+++ b/vm/nga-c/utf32.c
@@ -0,0 +1,5 @@
+int utf32_length(int *s, int max) {
+  int l = 0;
+  while (*s++ != 0 && l < max) l++;
+  return l;
+}