diff --git a/pkg/interop/util/util.go b/pkg/interop/util/util.go
index 1f05d4941..1aba144cb 100644
--- a/pkg/interop/util/util.go
+++ b/pkg/interop/util/util.go
@@ -1,12 +1,19 @@
+/*
+Package util contains some special useful functions that are provided by compiler and VM.
+*/
 package util
 
-// FromAddress is an utility function that converts an NEO address to its hash.
+// FromAddress is an utility function that converts a Neo address to its hash
+// (160 bit BE value in a 20 byte slice). It can only be used for strings known
+// at compilation time, because the convertion is actually being done by the
+// compiler.
 func FromAddress(address string) []byte {
 	return nil
 }
 
-// Equals compares a with b and will return true whether a and b
-// are equal.
+// Equals compares a with b and will return true when a and b are equal. It's
+// implemented as an EQUAL VM opcode, so the rules of comparison are those
+// of EQUAL.
 func Equals(a, b interface{}) bool {
 	return false
 }