added tests as prepared by oliver

test/ref/cc65101209.c

@@ -0,0 +1,38 @@
+/*
+  !!DESCRIPTION!! mod operator bug
+  !!ORIGIN!!      testsuite
+  !!LICENCE!!     Public Domain
+  !!AUTHOR!!      marcas
+*/
+
+#include <stdlib.h>
+#include <stdio.h>
+
+int main(void) {
+     int tmp;
+
+     for (tmp = 0; tmp<=12345; tmp++)
+         if (!(tmp%1000)) printf("%d mod 1000 is %d\n", tmp, tmp%1000);
+
+    return 0;
+}
+
+/*
+results in  (vice x64)
+0 mod 1000 is 0
+232 mod 1000 is 0
+1000 mod 1000 is 0
+
+Interesting:
+
+        1000    = $3E8
+        232     = $E8
+
+So testing with 999 gives:
+
+0 mod 999 is 0
+231 mod 999 is 0
+999 mod 999 is 0
+
+This seems to be systematic. 
+*/