diff --git a/inc-c/ufn/ufn_round.h b/inc-c/ufn/ufn_round.h
index 260ff0b..3ade400 100644
--- a/inc-c/ufn/ufn_round.h
+++ b/inc-c/ufn/ufn_round.h
@@ -1,13 +1,33 @@
+// ufn_round.h: More feature-rich rounding functions.
+// Under MIT-License. Copyright by Eric-Paul Ickhorn (epickh).
 
 #ifndef UFN_ROUND_H
 #define UFN_ROUND_H
 
 #include <stdint.h>
 
+/// @brief Rounds a value down to the last multiple of a stepping.
+/// @param value Value to round down (floor).
+/// @param stepping Stepping to round the value to.
+/// @return Rounded value
 int64_t ufn_floor_i64(int64_t value, int64_t stepping);
+
+/// @brief Rounds a value up to the next multiple of a stepping.
+/// @param value Value to round up (ceil).
+/// @param stepping Stepping to round the value to.
+/// @return Rounded value
 int64_t ufn_ceil_i64(int64_t value, int64_t stepping);
 
+/// @brief Rounds down (Floors) a value to the last power of 2.
+/// @param value Value to find the nearest lower power of 2 of.
+/// @return Power of 2 which is nearest lower one to 'value'.
 uint64_t ufn_floor_pow2(uint64_t value);
+
+/// @brief Rounds up (Ceils) a value to the next power of 2.
+/// @note Internally, this uses the 'ufn_floor_pow2'-function but multiplies
+///       its result by two to get the next higher power.
+/// @param value Value to round up to the next power of 2.
+/// @return Power of 2 which is the nearest higher one from 'value'/
 uint64_t ufn_ceil_pow2(uint64_t value);
 
 #ifdef UFN_IMPLEMENTATION