diff --git a/src/dat/nbt.c b/src/dat/nbt.c
index 6c2046f..54504e5 100644
--- a/src/dat/nbt.c
+++ b/src/dat/nbt.c
@@ -29,19 +29,6 @@ static int nbt_cmpstr(char const *restrict matstr, u8 const *restrict buf) {
 	return strncmp(str, matstr, len);
 }
 
-/* gets the tag size of primitive types, returns `>0` on success, `<0` on failure */
-int nbt_prim_tagsize(u8 tag) {
-	switch (tag) {
-	case NBT_I8:  return 1;
-	case NBT_I16: return 2;
-	case NBT_I32: return 4;
-	case NBT_I64: return 8;
-	case NBT_F32: return 4;
-	case NBT_F64: return 8;
-	default:      return -1;
-	}
-}
-
 /* returns the (expected) pointer of the tag following this one.
  * `NBT_COMPOUND` and `NBT_END` tags are not valid for this function and should be handled separately.
  * `NULL` is returned if anything went wrong. */
@@ -99,3 +86,15 @@ int nbt_proc(void **restrict datout, u8 const *restrict buf, size_t len) {
 	// TODO: finish function
 	return 0;
 }
+
+int nbt_prim_tagsize(u8 tag) {
+	switch (tag) {
+	case NBT_I8:  return 1;
+	case NBT_I16: return 2;
+	case NBT_I32: return 4;
+	case NBT_I64: return 8;
+	case NBT_F32: return 4;
+	case NBT_F64: return 8;
+	default:      return -1;
+	}
+}
diff --git a/src/dat/nbt.h b/src/dat/nbt.h
index 1fc6c5c..0295f40 100644
--- a/src/dat/nbt.h
+++ b/src/dat/nbt.h
@@ -5,6 +5,7 @@
 #include <stdbool.h>
 #include <stdlib.h>
 
+#include "../util/atrb.h"
 #include "../util/types.h"
 
 /* NBT (named binary tag) is a tree data structure. Tags have a numeric type ID, name and a payload.
@@ -34,3 +35,6 @@ enum nbt_tagid {
 };
 
 int nbt_proc(void **restrict datout, u8 const *restrict buf, size_t len);
+
+/* gets the tag size of primitive types, returns `>0` on success, `<0` on failure */
+atrb_const int nbt_prim_tagsize(u8 tag);