diff --git a/skeletons/INTEGER.c b/skeletons/INTEGER.c
index a51dd11..54a402b 100644
--- a/skeletons/INTEGER.c
+++ b/skeletons/INTEGER.c
@@ -158,7 +158,9 @@
 		} else {
 			scrsize = sizeof(scratch);
 			scr = scratch;
-			ret = snprintf(scr, scrsize, "%ld", accum);
+			ret = snprintf(scr, scrsize,
+				(specs && specs->field_unsigned)
+				?"%lu":"%ld", accum);
 		}
 		assert(ret > 0 && (size_t)ret < scrsize);
 		return (cb(scr, ret, app_key) < 0) ? -1 : ret;
@@ -554,6 +556,7 @@
 asn_dec_rval_t
 INTEGER_decode_uper(asn_codec_ctx_t *opt_codec_ctx, asn_TYPE_descriptor_t *td,
 	asn_per_constraints_t *constraints, void **sptr, asn_per_data_t *pd) {
+	asn_INTEGER_specifics_t *specs=(asn_INTEGER_specifics_t *)td->specifics;
 	asn_dec_rval_t rval = { RC_OK, 0 };
 	INTEGER_t *st = (INTEGER_t *)*sptr;
 	asn_per_constraint_t *ct;
@@ -611,7 +614,9 @@
 			ASN_DEBUG("Got value %ld + low %ld",
 				value, ct->lower_bound);
 			value += ct->lower_bound;
-			if(asn_long2INTEGER(st, value))
+			if((specs && specs->field_unsigned)
+				? asn_ulong2INTEGER(st, value)
+				: asn_long2INTEGER(st, value))
 				_ASN_DECODE_FAILED;
 			return rval;
 		}
@@ -657,6 +662,7 @@
 asn_enc_rval_t
 INTEGER_encode_uper(asn_TYPE_descriptor_t *td,
 	asn_per_constraints_t *constraints, void *sptr, asn_per_outp_t *po) {
+	asn_INTEGER_specifics_t *specs=(asn_INTEGER_specifics_t *)td->specifics;
 	asn_enc_rval_t er;
 	INTEGER_t *st = (INTEGER_t *)sptr;
 	const uint8_t *buf;
@@ -673,21 +679,41 @@
 
 	if(ct) {
 		int inext = 0;
-		if(asn_INTEGER2long(st, &value))
-			_ASN_ENCODE_FAILED;
-		/* Check proper range */
-		if(ct->flags & APC_SEMI_CONSTRAINED) {
-			if(value < ct->lower_bound)
-				inext = 1;
-		} else if(ct->range_bits >= 0) {
-			if(value < ct->lower_bound
-			|| value > ct->upper_bound)
-				inext = 1;
+		if(specs && specs->field_unsigned) {
+			unsigned long uval;
+			if(asn_INTEGER2ulong(st, &uval))
+				_ASN_ENCODE_FAILED;
+			/* Check proper range */
+			if(ct->flags & APC_SEMI_CONSTRAINED) {
+				if(uval < (unsigned long)ct->lower_bound)
+					inext = 1;
+			} else if(ct->range_bits >= 0) {
+				if(uval < (unsigned long)ct->lower_bound
+				|| uval > (unsigned long)ct->upper_bound)
+					inext = 1;
+			}
+			ASN_DEBUG("Value %lu (%02x/%d) lb %lu ub %lu %s",
+				uval, st->buf[0], st->size,
+				ct->lower_bound, ct->upper_bound,
+				inext ? "ext" : "fix");
+			value = uval;
+		} else {
+			if(asn_INTEGER2long(st, &value))
+				_ASN_ENCODE_FAILED;
+			/* Check proper range */
+			if(ct->flags & APC_SEMI_CONSTRAINED) {
+				if(value < ct->lower_bound)
+					inext = 1;
+			} else if(ct->range_bits >= 0) {
+				if(value < ct->lower_bound
+				|| value > ct->upper_bound)
+					inext = 1;
+			}
+			ASN_DEBUG("Value %ld (%02x/%d) lb %ld ub %ld %s",
+				value, st->buf[0], st->size,
+				ct->lower_bound, ct->upper_bound,
+				inext ? "ext" : "fix");
 		}
-		ASN_DEBUG("Value %ld (%02x/%d) lb %ld ub %ld %s",
-			value, st->buf[0], st->size,
-			ct->lower_bound, ct->upper_bound,
-			inext ? "ext" : "fix");
 		if(ct->flags & APC_EXTENSIBLE) {
 			if(per_put_few_bits(po, inext, 1))
 				_ASN_ENCODE_FAILED;
diff --git a/skeletons/INTEGER.h b/skeletons/INTEGER.h
index b87c794..8411bfc 100644
--- a/skeletons/INTEGER.h
+++ b/skeletons/INTEGER.h
@@ -30,6 +30,8 @@
 	int map_count;				/* Elements in either map */
 	int extension;				/* This map is extensible */
 	int strict_enumeration;			/* Enumeration set is fixed */
+	int field_width;			/* Size of native integer */
+	int field_unsigned;			/* Signed=0, unsigned=1 */
 } asn_INTEGER_specifics_t;
 
 asn_struct_print_f INTEGER_print;
diff --git a/skeletons/NativeEnumerated.c b/skeletons/NativeEnumerated.c
index b6b47e1..1554220 100644
--- a/skeletons/NativeEnumerated.c
+++ b/skeletons/NativeEnumerated.c
@@ -196,7 +196,7 @@
 	/*
 	 * X.691, #10.6: normally small non-negative whole number;
 	 */
-	ASN_DEBUG("value = %d, ext = %d, inext = %d, res = %d",
+	ASN_DEBUG("value = %ld, ext = %d, inext = %d, res = %ld",
 		value, specs->extension, inext,
 		value - (inext ? (specs->extension - 1) : 0));
 	if(uper_put_nsnnwn(po, value - (inext ? (specs->extension - 1) : 0)))
diff --git a/skeletons/NativeInteger.c b/skeletons/NativeInteger.c
index b251ee7..abdb71a 100644
--- a/skeletons/NativeInteger.c
+++ b/skeletons/NativeInteger.c
@@ -48,6 +48,7 @@
 NativeInteger_decode_ber(asn_codec_ctx_t *opt_codec_ctx,
 	asn_TYPE_descriptor_t *td,
 	void **nint_ptr, const void *buf_ptr, size_t size, int tag_mode) {
+	asn_INTEGER_specifics_t *specs=(asn_INTEGER_specifics_t *)td->specifics;
 	long *native = (long *)*nint_ptr;
 	asn_dec_rval_t rval;
 	ber_tlv_len_t length;
@@ -105,7 +106,9 @@
 		tmp.buf = (uint8_t *)unconst_buf.nonconstbuf;
 		tmp.size = length;
 
-		if(asn_INTEGER2long(&tmp, &l)) {
+		if((specs&&specs->field_unsigned)
+			? asn_INTEGER2ulong(&tmp, &l)
+			: asn_INTEGER2long(&tmp, &l)) {
 			rval.code = RC_FAIL;
 			rval.consumed = 0;
 			return rval;
@@ -167,6 +170,7 @@
 NativeInteger_decode_xer(asn_codec_ctx_t *opt_codec_ctx,
 	asn_TYPE_descriptor_t *td, void **sptr, const char *opt_mname,
 		const void *buf_ptr, size_t size) {
+	asn_INTEGER_specifics_t *specs=(asn_INTEGER_specifics_t *)td->specifics;
 	asn_dec_rval_t rval;
 	INTEGER_t st;
 	void *st_ptr = (void *)&st;
@@ -182,7 +186,9 @@
 		opt_mname, buf_ptr, size);
 	if(rval.code == RC_OK) {
 		long l;
-		if(asn_INTEGER2long(&st, &l)) {
+		if((specs&&specs->field_unsigned)
+			? asn_INTEGER2ulong(&st, &l)
+			: asn_INTEGER2long(&st, &l)) {
 			rval.code = RC_FAIL;
 			rval.consumed = 0;
 		} else {
@@ -205,6 +211,7 @@
 NativeInteger_encode_xer(asn_TYPE_descriptor_t *td, void *sptr,
 	int ilevel, enum xer_encoder_flags_e flags,
 		asn_app_consume_bytes_f *cb, void *app_key) {
+	asn_INTEGER_specifics_t *specs=(asn_INTEGER_specifics_t *)td->specifics;
 	char scratch[32];	/* Enough for 64-bit int */
 	asn_enc_rval_t er;
 	const long *native = (const long *)sptr;
@@ -214,7 +221,9 @@
 
 	if(!native) _ASN_ENCODE_FAILED;
 
-	er.encoded = snprintf(scratch, sizeof(scratch), "%ld", *native);
+	er.encoded = snprintf(scratch, sizeof(scratch),
+			(specs && specs->field_unsigned)
+			? "%lu" : "%ld", *native);
 	if(er.encoded <= 0 || (size_t)er.encoded >= sizeof(scratch)
 		|| cb(scratch, er.encoded, app_key) < 0)
 		_ASN_ENCODE_FAILED;
@@ -227,6 +236,7 @@
 	asn_TYPE_descriptor_t *td,
 	asn_per_constraints_t *constraints, void **sptr, asn_per_data_t *pd) {
 
+	asn_INTEGER_specifics_t *specs=(asn_INTEGER_specifics_t *)td->specifics;
 	asn_dec_rval_t rval;
 	long *native = (long *)*sptr;
 	INTEGER_t tmpint;
@@ -244,7 +254,9 @@
 	rval = INTEGER_decode_uper(opt_codec_ctx, td, constraints,
 				   &tmpintptr, pd);
 	if(rval.code == RC_OK) {
-		if(asn_INTEGER2long(&tmpint, native))
+		if((specs&&specs->field_unsigned)
+			? asn_INTEGER2ulong(&tmpint, native)
+			: asn_INTEGER2long(&tmpint, native))
 			rval.code = RC_FAIL;
 		else
 			ASN_DEBUG("NativeInteger %s got value %ld",
@@ -258,6 +270,7 @@
 asn_enc_rval_t
 NativeInteger_encode_uper(asn_TYPE_descriptor_t *td,
 	asn_per_constraints_t *constraints, void *sptr, asn_per_outp_t *po) {
+	asn_INTEGER_specifics_t *specs=(asn_INTEGER_specifics_t *)td->specifics;
 	asn_enc_rval_t er;
 	long native;
 	INTEGER_t tmpint;
@@ -269,7 +282,9 @@
 	ASN_DEBUG("Encoding NativeInteger %s %ld (UPER)", td->name, native);
 
 	memset(&tmpint, 0, sizeof(tmpint));
-	if(asn_long2INTEGER(&tmpint, native))
+	if((specs&&specs->field_unsigned)
+		? asn_ulong2INTEGER(&tmpint, native)
+		: asn_long2INTEGER(&tmpint, native))
 		_ASN_ENCODE_FAILED;
 	er = INTEGER_encode_uper(td, constraints, &tmpint, po);
 	ASN_STRUCT_FREE_CONTENTS_ONLY(asn_DEF_INTEGER, &tmpint);
@@ -282,6 +297,7 @@
 int
 NativeInteger_print(asn_TYPE_descriptor_t *td, const void *sptr, int ilevel,
 	asn_app_consume_bytes_f *cb, void *app_key) {
+	asn_INTEGER_specifics_t *specs=(asn_INTEGER_specifics_t *)td->specifics;
 	const long *native = (const long *)sptr;
 	char scratch[32];	/* Enough for 64-bit int */
 	int ret;
@@ -290,7 +306,9 @@
 	(void)ilevel;	/* Unused argument */
 
 	if(native) {
-		ret = snprintf(scratch, sizeof(scratch), "%ld", *native);
+		ret = snprintf(scratch, sizeof(scratch),
+			(specs && specs->field_unsigned)
+			? "%lu" : "%ld", *native);
 		assert(ret > 0 && (size_t)ret < sizeof(scratch));
 		return (cb(scratch, ret, app_key) < 0) ? -1 : 0;
 	} else {