Add comments.

ms.h

@@ -8,10 +8,21 @@
 #include <string.h>
 #include <sys/wait.h>
 
+/* Merge arrays left and right into res array.
+ */
 void mymerge(int left[], size_t leftlen, int right[], size_t rightlen, int res[]);
 
+/* Sort arr of size len using mergesort.
+ */
 int mymergesort(int arr[], size_t len);
 
+/* Sort arr of size len using mergesort.
+ * This function uses parallel processes for sorting.
+ * It is implemented by forking new process for right
+ * part of array. New child is forked only if 
+ * current subarray len is less or equal than original
+ * array len / cnt parameter.
+ */
 int mymergesortp(int arr[], size_t len, int cnt);
 
 #endif