guard PER references
diff --git a/skeletons/BMPString.c b/skeletons/BMPString.c
index b6348c1..ce8874b 100644
--- a/skeletons/BMPString.c
+++ b/skeletons/BMPString.c
@@ -33,8 +33,13 @@
OCTET_STRING_encode_der,
BMPString_decode_xer, /* Convert from UTF-8 */
BMPString_encode_xer, /* Convert to UTF-8 */
+#ifdef ASN_DISABLE_PER_SUPPORT
+ 0,
+ 0,
+#else
OCTET_STRING_decode_uper,
OCTET_STRING_encode_uper,
+#endif /* ASN_DISABLE_PER_SUPPORT */
0, /* Use generic outmost tag fetcher */
asn_DEF_BMPString_tags,
sizeof(asn_DEF_BMPString_tags)