add div64 and mod64

llrtc/lib/div64.c

@@ -0,0 +1,11 @@
+#include "llrt.h"
+
+uint64_t udiv64(uint64_t dividend, uint64_t divisor)
+{
+    return udivmod64(dividend, divisor, NULL);
+}
+
+int64_t sdiv64(int64_t dividend, int64_t divisor)
+{
+    return sdivmod64(dividend, divisor, NULL);
+}