diff --git a/src/runtime/hashmap.go b/src/runtime/hashmap.go
index c8c12419..1da9e962 100644
--- a/src/runtime/hashmap.go
+++ b/src/runtime/hashmap.go
@@ -41,11 +41,11 @@ type hashmapBucket struct {
 }
 
 type hashmapIterator struct {
-	buckets      unsafe.Pointer
-	numBuckets   uintptr
-	bucketNumber uintptr
-	bucket       *hashmapBucket
-	bucketIndex  uint8
+	buckets      unsafe.Pointer // pointer to array of hashapBuckets
+	numBuckets   uintptr        // length of buckets array
+	bucketNumber uintptr        // current index into buckets array
+	bucket       *hashmapBucket // current bucket in chain
+	bucketIndex  uint8          // current index into bucket
 }
 
 // Get the topmost 8 bits of the hash, without using a special value (like 0).