diff --git a/src/patch/mod.rs b/src/patch/mod.rs
index eaaff2f1..cff18b62 100644
--- a/src/patch/mod.rs
+++ b/src/patch/mod.rs
@@ -639,6 +639,7 @@ fn check_offsets(offsets: &[u32], dim_increment: u32) -> bool {
     true
 }
 
+/// Compare 2 strings and return index of first different char
 fn first_diff(s1: &str, s2: &str) -> usize {
     for ((i, c1), c2) in s1.char_indices().zip(s2.chars()) {
         if c1 != c2 {
@@ -647,6 +648,7 @@ fn first_diff(s1: &str, s2: &str) -> usize {
     }
     s1.len().min(s2.len())
 }
+/// Replace first occurrence of `pat` in string starting from byte `i`
 fn replacefirstfrom<'a>(s: &'a str, pat: &str, to: &str, i: usize) -> Cow<'a, str> {
     if i >= s.len() {
         s.into()
@@ -655,6 +657,8 @@ fn replacefirstfrom<'a>(s: &'a str, pat: &str, to: &str, i: usize) -> Cow<'a, st
         format!("{s1}{}", &s2.replacen(pat, to, 1)).into()
     }
 }
+/// Tries to get common description (or displayNames) for register/field array with "%s" in index position.
+/// Returns `None` if incoming descriptions have more then 1 difference
 fn common_description(descs: &[Option<&str>], dim_index: &[String]) -> Option<Option<String>> {
     let mut start = 0;
     if descs.len() > 1 {